# Model boiler design information



## Dan Rowe (Mar 30, 2010)

One of the best sources of information on model boiler design is the Australian Miniature Boiler Safety Committee. (AMBSC) The four books (1) Copper (2) Steel (3) Sub-miniature and (4) Duplex Steel 
http://www.smex.net.au/Store/Store_AALS-Codes.php

Model Boilers & Boilermaking by K. N. Harris has a wealth of good design information and construction methods. Topics covered include fuel and firing and accessories. (Copper boilers)

Model Locomotive Boilers by Martin Evans is also a good source of design information and methods. It covers welding equipment, workshop equipment, water, fuel and combustion, oil and gas firing, and testing. The testing is more than a simple hydro a full engineering test stand designed by J. Ewins is described with drawings of the boiler and test results. (Copper and steel boilers)

Safety of Copper Boilers by Kozo Hiraoka this nine page article was first in Live Steam & O.R. (Vol. 40 No. 6 Nov-Dec 2006) and is included in Building the New Shay. The design rules are presented in graph form for simplicity with the ASME formulas and code designation listed in the appendix. All graphs have a metric and an imperial version. The graphs are (1) Minimum thickness for a cylindrical shell under internal pressure (2) Maximum allowable pitch of symmetrically arranged staybolts (3) Maximum allowable diameter of a circle enclosing an unstayed surface area (4) Minimum staybolt diameter. This book like all of Kozos books is a treasure trove of useful information for the model engineer.

These are the four main sources of model boiler information in my stack. Several other model engineering books I own have boiler chapters but the information is not a complete design system. These include works by Greenly, LBSC, Tubal Cain, and Martin Evans.

Cheers Dan


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## xo18thfa (Mar 30, 2010)

Dan: Do you have a copy of the AMBSC?


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## Dan Rowe (Mar 31, 2010)

Yes Bob,
I have a copy of all 3 sections of the AMBSC and I have read each one cover to cover more than once.
That is the reason I recomended it as a very good source of boiler design information.
Cheers Dan


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## steamboatmodel (Mar 31, 2010)

Hi Dan,
What is the difference between a Miniature and a Sub-Miniature Boiler?
The Australian Miniature Boiler Code - Copper Boilers. $24.40 
The Australian Sub-Miniature Boiler Code. $12.00 
Regards,
Gerald.


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## Dan Rowe (Mar 31, 2010)

Hi Gerald,
Here is a link to another source of the AMBSC boiler code with miniature and sub-miniature limits. There is also a link for the index of all three books. http://www.smex.net.au/Store/Store_AALS-Codes.php

Basically the sub-miniature AMBSC is a lot more relaxed for boilers 3" OD, 75psi, 1 liter capacity and below.

Cheers Dan


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## xo18thfa (Mar 31, 2010)

Dan Rowe  said:
			
		

> Yes Bob,
> I have a copy of all 3 sections of the AMBSC and I have read each one cover to cover more than once.
> That is the reason I recomended it as a very good source of boiler design information.
> Cheers Dan



The reason I ask is because I was wondering how Kozo's article in the new Shay book compares.

Bob


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## Dan Rowe (Apr 1, 2010)

If you compare the index to AMBSC Part 1 and the index I copied from Kozo Hiraoka paper on the Safety of Copper Boilers you will see that they both cover approximately the same material. Kozos work is directly traceable to the ASME code with all references given. Kozo states The ASME code is more conservative than prevailing model engineering practice, this most likely includes the AMBSC. The choice of which design system to use is often dictated by the location of the builder. 

I like the AMBSC nomogram for solving the relationship between boiler pressure, heating surface and safety valve orifice diameter better than what Kozo presents on this topic. For the same reason I think the graphs in Kozos article make working the calculations and what ifs simpler. The AMBSC has a lot more drawings of design examples and I like a lot of drawings with my model engineering. 

The link for the index to AMBSC Code Part 1 Issue 7-2001: Copper Boilers is here: http://www.smex.net.au/Store/Data/AMBSC_Code1-Idx.htm

Safety of Copper Boilers by Kozo Hiraoka
Index
1 Advantage of Copper Boilers
2 Reference Code (ASME Sec I, Sec II, Sec VIII)
3 Safety of Copper Boilers
3.1 Materials
3.2 Cylindrical Shells Under Internal Pressure
3.3.1 Surface Stayed with Symmetrically Spaced Staybolts
3.3.2 Surfaces Stayed with Irregularly Spaced Staybolts
3.4 Specifications of Plate Thickness
3.5 Staybolts
3.6 Ribs
3.7 Crownsheet Stays
3.8 Joints
3.9 Hydrostatic Test
3.10.1 Water Gauge
3.10.2 Pressure Gauge
3.11 Water 
Appendix 1 Boilers Fabricated by Brazing in Section I ASME Code
Appendix 2 Cylinder Componets Under Pressure
Appendix 3 Flat Surface Stayed with Symmetrically Spaced Staybolts
Appendix 4 Staybolts   
Appendix 5 Hydrostatic Test Pressure
 5.1 Section I Power Boilers of ASME Code
 5.2 Section VIII Pressure Vessels of ASME Code
Appendix 6 Boiler Fittings (Section I Power Boilers)
 6.1 Water Gauge
 6.2 Pressure Gauge
 6.3 Safety Valve

Cheers Dan


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## steamboatmodel (Apr 2, 2010)

Dan Rowe  said:
			
		

> Hi Gerald,
> Here is a link to another source of the AMBSC boiler code with miniature and sub-miniature limits. There is also a link for the index of all three books. http://www.smex.net.au/Store/Store_AALS-Codes.php
> 
> Basically the sub-miniature AMBSC is a lot more relaxed for boilers 3" OD, 75psi, 1 liter capacity and below.
> ...


Thanks Dan,
It looks like the sub-miniature AMBSC is what I will add to my shelf next to the Harris's books.
Regards,
Gerald.


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## Dan Rowe (Apr 5, 2010)

Can any of the UK members tell me where I can read or buy a current UK model boiler code for copper boilers?
Both Harris and Evans were from the 1960's can they still be used for modern practice in the UK?

Dan


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## xo18thfa (Apr 5, 2010)

Dan Rowe  said:
			
		

> Can any of the UK members tell me where I can read or buy a current UK model boiler code for copper boilers?
> Both Harris and Evans were from the 1960's can they still be used for modern practice in the UK?
> 
> Dan



Harris talks about rivet and soft solder caulk construction. 

Never heard a reason why that is so bad.


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## Dan Rowe (Apr 5, 2010)

I found the answer to my question about UK boiler code at the end firebird's small boiler thread reply #395 by SandyC. http://www.homemodelenginemachinist.com/index.php?topic=2092.390

Here is another good thread about UK boiler rules.
http://www.homemodelenginemachinist.com/index.php?topic=1886.0

Cheers Dan


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## GWRdriver (Apr 5, 2010)

> Harris talks about rivet and soft solder caulk construction. . . Never heard a reason why that is so bad.


Hi Bob,
I've never seen a published point by point explanation of why, but when in the opinion of the overwhelming majority of designers and builders in the modern industrialized live steaming nations says abandon soft solder construction and to unilaterally adopt silver solder, I won't be wasting any of my time trying to argue and prove them wrong. My own take on the reason for it is it's not that soft solder construction is so bad, so much as silver solder construction is so good. It's just plain better technology. My understanding is the main problems with soft solder occured in fireboxes where even if 100% if the reqiired structural strength of the boiler was developed in the fasteners and staying, and that would not always be the case, the heat of coal fires is such that the soft solder caulking would break down and failures would occur.

Although I don't know for sure, because I only have the previous edition, I think in the latest edition of Harris the references to soft solder construction have been deleted or annotated.
Harry


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## xo18thfa (Apr 5, 2010)

GWRdriver  said:
			
		

> Hi Bob,
> I've never seen a published point by point explanation of why, but when in the opinion of the overwhelming majority of designers and builders in the modern industrialized live steaming nations says abandon soft solder construction and to unilaterally adopt silver solder, I won't be wasting any of my time trying to argue and prove them wrong. My own take on the reason for it is it's not that soft solder construction is so bad, so much as silver solder construction is so good. It's just plain better technology. My understanding is the main problems with soft solder occured in fireboxes where even if 100% if the reqiired structural strength of the boiler was developed in the fasteners and staying, and that would not always be the case, the heat of coal fires is such that the soft solder caulking would break down and failures would occur.
> 
> Although I don't know for sure, because I only have the previous edition, I think in the latest edition of Harris the references to soft solder construction have been deleted or annotated.
> Harry



Thanks Harry. I have the 7th edition of Harris (1977) and it's on page 33 (end of Ch 2) where he talks very briefly about it. I don't recall him mentioning it anywhere else, and he certianly does not specify it as a procedure.

I would not use soft solder caulk. Just wondering why it fell out of favor. As you know, I am a big fan of LBSC and he always used it for sealing mechanically secured stays inside a firebox.

Take care 

As you know, I am a big fan of LBSC. He used soft solder a lot to caulk mechanically secured stays inside a firebox.


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## Maryak (Apr 5, 2010)

xo18thfa  said:
			
		

> Thanks Harry. I have the 7th edition of Harris (1977) and it's on page 33 (end of Ch 2) where he talks very briefly about it. I don't recall him mentioning it anywhere else, and he certianly does not specify it as a procedure.



Try page 86 on Caulking. (2000 edition).




			
				xo18thfa  said:
			
		

> I would not use soft solder caulk. Just wondering why it fell out of favor. As you know, I am a big fan of LBSC and he always used it for sealing mechanically secured stays inside a firebox.



Section 2.6 of my copy of AMBSC for Copper boilers permits the use of 60/40 or 70/30 soft solder as caulking materials.

Best Regards
Bob


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## Dan Rowe (Apr 7, 2010)

I checked the document linked by JasonB on the US boiler code thread for mention of soft solder. This is what I found:

*SPECIFIC REQUIREMENTS FOR
NON-COMMERCIALLY BUILT COPPER BOILERS*
The materials used for silver soldered or riveted/soft solder caulked boilers must be suitable for purpose, although material certification is not required when these forms of construction are adopted.

Complete text: http://www.ntet.co.uk/pdf/miniatures_exam_and_test_code_nov_08.pdf

So I know that the formulas for the strength of boilers in both Harris and Evans are the same formulas used by all engineers for this type of calculation. The devil is in the details like what is the assumed max stress for copper and if there is material temperature compensation applied. Harris does not have a temperature factor and Evans does. The Maryland model code is temperature compensated. The AMBSC simply specifyes the minimum plate thickness for various pressures allowed. Kozo's paper uses a graphical method with temperature compensation and formulas given in appendix.

So to get to the point can some UK member verify that the formulas in Harris can be used for current UK model pressure vessel calculations?

Cheers Dan


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## ianjkirby (Apr 12, 2010)

Hi guys,

 I would like to add the following just for clarification.

 AMBSC code part 1 is for copper boilers up to 203mm dia, 25 litres water capacity, and 700kPa.
 AMBSC code part 2 is for carbon steel boilers up to 255mm dia, 50 litres water capacity, and 700 kPa.
 AMBSC code part 3 is for boilers than up to 76mm dia, 1 litre water capacity, and 520 kPa.

 A proposal for the use of stainless steel alloy 2205 (a duplex alloy, and quite specific in its welding requirements) is currently being investigated, and looks to be suitable at this point in time. Approval of statutory authorities is the next step in the process.

 Part 3 is essentially for gauge 1 (or garden gauges) non-passenger-hauling locomotives, and R/C model boats, and other similarly powered vehicles.

 With regards to the use of common (or leaded) soft solder, it is allowed in AMBSC for caulking purposes, but is highly discouraged for the fact that if it fails to fix leaks, repairs using silver solder are practically impossible, because it (silver solder) will not take over soft solder. If you need to fix a leak, try silver solder first. You will usually only get one chance with soft solder.

Regards, Ian.

(Recently retired Chairman, AMBSC)


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## xo18thfa (Apr 12, 2010)

I think I need a copy of Part 3


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## ianjkirby (Apr 13, 2010)

Hi Bob,
 The AMBSC codes are available from sources in earlier posts in this thread. Please keep in mind that they are only legal in Australia and NZ. They may be used as guides any where in the world, but have no authority outside Oz & NZ.
Regards, Ian.


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## xo18thfa (Apr 13, 2010)

It's an up-to-date guide for sure. I just want to make sure what I am doing is right.


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## clippermaniac (May 8, 2010)

The folks from Chesapeake and Allegeny Live Steamers have some useful stuff as well. Links to follow

http://www.calslivesteam.org/calboil1.htm
http://www.calslivesteam.org/calculations/Calculations.htm

Jim


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## steamboatmodel (May 9, 2010)

xo18thfa  said:
			
		

> I think I need a copy of Part 3


I ordered a copy and received it very quickly. It is very well written and easy to understand a good buy.
Regards,
Gerald.


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## Nave (Jul 10, 2010)

Hi,

I'm just starting this myself and bought Harris and Parts 2&3 of the AMSC codes. Part 2 contains a lot of stuff I found useful when trying to work in the fitting locations, such as the sizes for various bushes and the min web in the tube plate. Given that harris is pretty thin on detail in his final design chapters, this was invaluable.

Dave.


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## Diversion900 (Jul 11, 2010)

Just a quick question for the Aussies in the know....

My planned build of a inglis type Scotch boiler 100mm diam. but under 1 litre capacity, would this fall under code 3 regulations, or code 1 ?



Cheers, Neil


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## ianjkirby (Jul 11, 2010)

Hi Neil,
 The codes are quite clear. In each of them, the "scope", or range of parameters allowable, is unambiguously stated.
 Code part 3 has a maximum allowable diameter of 76mm, so your proposed 100mm dia boiler is clearly within the scope of code part 1. The fact that it is only 1 litre is of no consequence.
 All parameters must be met simultaneously; barrel size, water volume, and pressure have stated limits. If any one of those limits is exceeded, then the next level applies. If any parameter of code part 1 is exceeded, then the boiler must be approved and inspected by commercial inspectors if insurance is required.
 Above all, please discuss the matter with your local club boiler inspector.
Regards, Ian.
(ex-AMBSC chairman)


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## Diversion900 (Jul 11, 2010)

Thanks Ian, much appreciated. I've been wondering about this for a while now.

I have been given the name of a local club boiler man, so I will track him down and discuss the build further to get my head around the rules and regs before proceding too far.

Cheers, Neil


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## Dan Rowe (Feb 18, 2011)

The last chapter in Martin Evens "Model Locomotive Biolers" is about testing boilers for efficiency which is the work of Jim Ewins. The chapter describes the test set up and results obtained from the testing.

Now here is the good bit. I found a website that takes Jim Ewins research and placed it in excel so initial boiler design can be checked and compared to existing designs.
http://www.baggo.copperstream.co.uk/me/Loco%20design/design1.htm
http://www.modeng.johnbaguley.info/Loco design/design1.htm

A further page on this subject by Jim Ewins can be found here:
http://www.modeleng.org/articles/loco_research_je.pdf

Dan


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## xo18thfa (Feb 18, 2011)

Nice find Dan. That's handy info.

I finally ordered a Part III manual on sub-miniature boilers ans the steel boiler manual.


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## steamboatmodel (Jan 4, 2012)

Dan Rowe  said:
			
		

> The last chapter in Martin Evens "Model Locomotive Biolers" is about testing boilers for efficiency which is the work of Jim Ewins. The chapter describes the test set up and results obtained from the testing.
> 
> Now here is the good bit. I found a website that takes Jim Ewins research and placed it in excel so initial boiler design can be checked and compared to existing designs.
> http://www.baggo.copperstream.co.uk/me/Loco design/design1.htm
> ...


Hi Dan,
The http://www.baggo.copperstream.co.uk/me/Loco design/design1.htm
Is no longer working.
Regards,
Gerald.


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## Dan Rowe (Jan 5, 2012)

Hi Gerald,
It took me a bit to track down John Baguley's new website. The information about locomotive design using Jim Ewins system is here:
http://www.modeng.johnbaguley.info/

Dan


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## steamboatmodel (Jan 5, 2012)

Thanks Dan.
Its too bad that we can't get some of this information in a sticky.
Regards,
Gerald.


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## steamboatmodel (Feb 27, 2012)

Now that this is a sticky of some books;
Books 
________________________________________
Here is a short list of Books.
(Maybe not so short ;<)

K.N Harris's book Model Boilers and Boilermaking. 
(This one is almost considered the Bible among Boiler Makers)
Found online PDF copy:
http://www.fastonline.org/CD3WD_40/JF/424/19-422.pdf

"Model Stationary and Marine Steam Engines" by K.N.Harris
Found online PDF copy:
http://www.fastonline.org/CD3WD_40/JF/424/19-423.pdf

The next two have simple pot boilers in them;
Building Simple Model Steam Engines 
Books 1 & 2 
by Tubal Cain 

Making Simple Model Steam Engines 
Model Marine Steam 
by Stan Bray 

Another Article/book to add,
Safety of Copper Boilers by Kozo Hiraoka this nine page article was first in Live Steam & O.R. (Vol. 40 No. 6 Nov-Dec 2006) and is included in Building the New Shay.

For those who want to really move along.
"Experimental Flash Steam" by J.H.Benson and A.A.Rayman.

This link applies more to full size equipment than models, but does cover steam basics;
http://www.pipingnews.com/steam2.htm

Not really a book but usefull,I found this years back
The Truth about Steam Oil
by Harry Wade 
http://www.southernsteamtrains.com/m...-oil-hwade.htm
Regards,
Gerald.


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## Bentwings (Jan 14, 2022)

Dan Rowe said:


> One of the best sources of information on model boiler design is the Australian Miniature Boiler Safety Committee. (AMBSC) The four books (1) Copper (2) Steel (3) Sub-miniature and (4) Duplex Steel
> http://www.smex.net.au/Store/Store_AALS-Codes.php
> 
> Model Boilers & Boilermaking by K. N. Harris has a wealth of good design information and construction methods. Topics covered include fuel and firing and accessories. (Copper boilers)
> ...


I didn’t know this section was on here. I’ve posed some already about my new hobby,,,,steam engines an boilers.

 Have.  4 cyl piston port mill stem engine ordered from chilertern in uk. They have been absolutely wonderful to deal with. I get overnight emails even though theeis 6 hours difference.
in my situation I simpl. Cannot have a fuel fired beer. I’ll have t use an ultra quivering compressor for initial start uwhhile I’m building the  electrically heated boiler I write some about it already in the steam nine group. It’s 44” da meter 6062 aluminum 3/16 wall tube. I initially thought of makin it from a solid bar f aluminum, but between it being early wasteful even though I have a solid bar of 4” aluminum, it meant cutting threads internally on or ennd externally on a screw in end cap,  it involved a lot of work I’m visually impaired ou will se spelling errors making some out of context things appear. I’m medically not even supposed to be in the shop. I have to use magnifying glass use to read micrometer. Lus the shop is 60 miles away so I have limited time there too. While I lit screw in cap would have been stronger I really wanted ssuprr high pressures. . I’m new to boilers so I had to do some self educating. I’m a life long mechanical ngineer anddtool. Maker welder. So I don’t have fabrication problems other an those I create myself. I hav access to solid works but limited. I hate manual drawing boards  but have to give in to my med issues and make endless sketches and calculations.  So enough. 
 I’ve determined my boiler is a heated water boiler not a fire tube boile like a locomotive. I hav a 50watt anda1200 watt electric immersion heaters. I was only going to use one ut I can plu theminto different circuits in my home.they should provide enough heat. The oiler has 10 1/2” ter tubes mounted in two aluminum ulheads . With heater going under them.the end caps have Teflon o rings it’s thee made by a retaining late oorming one side of the groove.that way th o ring does not have to be stretched over g of he groove. The engin pistons. Are made the same way.there will be a row of 8 NPT female fitting ports tapped in the upper or top of the tube for outlet boilerr I’ll pressure age tem gage plushe end cap will hav ports for levee and das well a ande port.  May use a stainless steel center tie rod for extra safety. I’ve done hoop stress including the ring f button head end cap retaining screws. I think it is strong enough. I also have sketches for a simulation max  pressure test. I’ve done this in industry. So I’m eelamiliarwith this. Test. We have a hyydaulic pump so I’ll be s
able to pressurize the test fixture t faailre when the time come it will be pressurized with water in a water tank so no explosions. It will fail by leaking first.  Also the boiler wilhave two mounting legs on s solid aluminum plate. I may use a hot plate to keep intermittent if necessary the boiler will be wrapped with  automotive exhaust header issuatingbwrap. Then a olished stainless steel decorative wrap.   So Er is lots going on. My son and grand sn wi help with the machine work. Normally I’d TIG WELD IT BUT I JUST CANT SEE WELL ENOUGH TO MAKE ACCEPTABLE WELD.    Did exactly this shortly after retirement but medically I can’t now.   Ivory material and I jstfiised the boilerr tubes . I had not planned using both h easters but I have I ont know j ha fast the engine will run but I plan on abo 1,000 rpm cruising. I have a cool dynamo an at least half a dozen stepper moors and another half a dozen small gear motors so plenty of experiential stuff. I forgot I have two stem turbine too.the on thing I just ran into is the onmiser o. Condenser. I’m trying to lesrn a little about these but for models probably not necessary. I’ll have lubicated stem or air so my initial thought is to use the turbines as centrifugeto strain the remaining oil out of the exhaust steam  air. I have an extra ir filter I can use too.  them so in they go.
 From my description aybe y’all could comment good o bad.I won’t have the engine for another couple weeks but I’ll start assembly right away As soon as it arrives. Take pictures  as progress goes on the boiler.maybe a video   E mounting board or floor is going to be 1/8” laminated oak oak strips in casting resin so it’s glass smooth. In other words a scale wood floor. I have a plastic mounting and assembly board now until eerthing is ready.everything is ready.
my kitty wants me to cne to bed so until later.

byron


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## Steamchick (Jan 15, 2022)

Hi Byron,
You'll need all the heaters you can stuff into the boiler. You'll have to have at least 2kW just for the smallest engine using a little more than a whiff of steam. As the outside will not have flames lapping over it, you can do a serious job of lagging. On my 3" boilers, I have a "radiant" barrier - aluminium foil, insulation spacer and aluminium foil - surrounded by 1/2" of conductive barrier. Balsa wood is very good for that! I have held the outside of the wood to warm my hands when at full pressure, but it isn't hot like a coffee mug. And I always lag the steam pipework as well, as otherwise the losses from that can be huge!

Dan, and colleagues, I am glad Byron has introduced me to this site via his post... 
I should like to let people know that the "Engineering" I do (crude calculations, and ideas) has caused me to "de-rate" some boilers that were "traditional" designs.
The simple reason is that copper in compression is really weak. (Compressive strength around 21% of the tensile strength at "boiler" temperatures). I haven't found ANY text book that covers this properly (I use properly in the sense that I have been a professional engineer all my career, and expect all the facets of a design to be covered). Typically, designs on tubes that are in compression, when larger than just flue tubes, are inadequate for the design pressure of boilers, and still have a factor of safety of 8. 
So do your sums lads! And check compressive hoop stress against the compressive strength of copper at elevated temperature, before you even order the tubes form the supplier.
Anyone wanting more advice (or calculations) please ask. I do this for free, so all your boilers are safe.
Enjoy steaming!
K2


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## Bentwings (Jan 15, 2022)

Steamchick said:


> Hi Byron,
> You'll need all the heaters you can stuff into the boiler. You'll have to have at least 2kW just for the smallest engine using a little more than a whiff of steam. As the outside will not have flames lapping over it, you can do a serious job of lagging. On my 3" boilers, I have a "radiant" barrier - aluminium foil, insulation spacer and aluminium foil - surrounded by 1/2" of conductive barrier. Balsa wood is very good for that! I have held the outside of the wood to warm my hands when at full pressure, but it isn't hot like a coffee mug. And I always lag the steam pipework as well, as otherwise the losses from that can be huge!
> 
> Dan, and colleagues, I am glad Byron has introduced me to this site via his post...
> ...


Thanks for your response.I too am a life long mech eng as well as tool maker. We have a small shop so machining is not a big problem except my mobility is limited to have
Ing some one come and get me then spend the rest of the day in the shop not all bad but my vision limits me to being extremely careful and having my ever present magnifying glass.   The boiler won’t have any closed copper tubes only the “ super heat” tubes I’m pretty sure the immersion heaters will be ok they are stainless steel and I’ve used them before in some plastic molds in industry.   Since I’ve even intoning boats I’m well aware of using anodes so that was a natural. My tap water is terrible my humidifier needs weekly cleaning there is constant lime issues. I go through coffee pots once a year at best. I asked about bronze and brass as the question came up at our daily lunch debates brass is easy to the point of fun to machine bronze is harder and much more expensive and harder to Er. But I have some of each. There are store bought fittings that I can get as needed some times there is a choice of materials. I’d just like to not create issues I can avoide right from the start.  My little engine is a 4 cyl double acting slide piston ported engine mill model from childrenmodelsteam in uk they have wonderful customer service I get email in less than half a day with 6 hour time difference .  So after your note the question is what is the displacement of this engine 17mm bore 19 mm stroke ? 4 cyl I don’t know the piston thickness but I’d guess 1/8” based on design Vince it’s 4 cyl double acting it’s actually an 8 cyl engine  three of us got different values. LOL  ITS LESS THAN 1 cu  in the object was to see if the air compressor can operate it for a while  it has a small tank and about 2.2 cam at 90 psi.
I’m thinking that the boiler will run about 50 psi with 100 psi max . I’m working on a small gear pump for filling on the fly. There are a couple piston pumps available but converted to steam engine driven are horribly noise for small item  plus overly expensive for what is purchased . Gear rod is readily available so I could change the size pretty easily I have at least half a dozen motors that th steamer could drive or I can dc power supply them so adding a check valve to the feed line should make filling the boiler easy .
Insulation the balsa wood idea is great  I have just a great pile of every size you can imagine plus I’ve done balsa model airplane for over 65 years so bending cutting shaping is something I think I have a handle on 
. I had planned on using automotive exhaust header wrap but the balsa will make this insulation much cleaner and easier. I also plan on a polished stainless decorative wrap. So it will now be much cleaner.  Originally I was going to make the boiler one piece with a threaded end cap on one end then it evolved to threaded in both ends then to button headed screws to simulate riveted now there will be just polished end caps I backed away from the threaded end because the thermo expansion could cause leaking which I want to avoid. There will 8  8-32 stainless steel screws plus the tie rod holding it together. I have a max pressure test set up too no not air? Hydraulic . I’ve done this in industry  so done this before 
Anyway I really need all the help and comments  I have thick skin so I can debate if necessary . I’ll keep politics out as I’m known to get on my invisible Podium 

byron


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## Bentwings (Jan 20, 2022)

Bentwings said:


> Thanks for your response.I too am a life long mech eng as well as tool maker. We have a small shop so machining is not a big problem except my mobility is limited to have
> Ing some one come and get me then spend the rest of the day in the shop not all bad but my vision limits me to being extremely careful and having my ever present magnifying glass.   The boiler won’t have any closed copper tubes only the “ super heat” tubes I’m pretty sure the immersion heaters will be ok they are stainless steel and I’ve used them before in some plastic molds in industry.   Since I’ve even intoning boats I’m well aware of using anodes so that was a natural. My tap water is terrible my humidifier needs weekly cleaning there is constant lime issues. I go through coffee pots once a year at best. I asked about bronze and brass as the question came up at our daily lunch debates brass is easy to the point of fun to machine bronze is harder and much more expensive and harder to Er. But I have some of each. There are store bought fittings that I can get as needed some times there is a choice of materials. I’d just like to not create issues I can avoide right from the start.  My little engine is a 4 cyl double acting slide piston ported engine mill model from childrenmodelsteam in uk they have wonderful customer service I get email in less than half a day with 6 hour time difference .  So after your note the question is what is the displacement of this engine 17mm bore 19 mm stroke ? 4 cyl I don’t know the piston thickness but I’d guess 1/8” based on design Vince it’s 4 cyl double acting it’s actually an 8 cyl engine  three of us got different values. LOL  ITS LESS THAN 1 cu  in the object was to see if the air compressor can operate it for a while  it has a small tank and about 2.2 cam at 90 psi.
> I’m thinking that the boiler will run about 50 psi with 100 psi max . I’m working on a small gear pump for filling on the fly. There are a couple piston pumps available but converted to steam engine driven are horribly noise for small item  plus overly expensive for what is purchased . Gear rod is readily available so I could change the size pretty easily I have at least half a dozen motors that th steamer could drive or I can dc power supply them so adding a check valve to the feed line should make filling the boiler easy .
> Insulation the balsa wood idea is great  I have just a great pile of every size you can imagine plus I’ve done balsa model airplane for over 65 years so bending cutting shaping is something I think I have a handle on
> ...


I just got a piece of 4” aluminum tube to serve as the mold for the stack of balsa I have waiting . The ammonia I won’t get until Sunday then I’ll start the boiler wrap insulation . I may still add the automotive exhaust wrap maybe even mold it right into the balsa.  I have 1/4 40 ME tap and die ordered also found 1/16” NPT TAP AND DIE actually found 1/116 pipe. I didn’t know it existed . I just got the pressure relief valve and spring set. I’m going to try and get to the shop over the week end. Also got s tooth belt an handful of pulleys. Snd a self aligning bearing for the engine outer crankshaft support. I haven’t modeled it yet but I have some ideas. It will be aluminum , maybe polished.  I still have some others parts coming. I have to make a choice shortly on gages and fittings. I’m thinking 1/8 NPT at present as a compromise size cost and space. The engine is supposed to arrive tomorrow. It’s might cold out now probably -15 F by morning . It time to start thawing my test oils out both are frozen solid.  I’m going to lay them flat and see when they start running or pouring . Then I’ll go from there.
Byron


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## chrsbrbnk (Jan 20, 2022)

Do I have this correct ,your planning on building a boiler out of 3/16 wall aluminum tube 4 inches in dia. . the end caps are held on with 8-32 screws and sealed with rubber o rings . your planning on running this at 50-100psi?


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## abby (Jan 20, 2022)

Nah it's 44" dia and 3/16 thick wall ! he was going to machine it from a solid bar but it was a bit wasteful .


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## Bentwings (Jan 20, 2022)

chrsbrbnk said:


> Do I have this correct ,your planning on building a boiler out of 3/16 wall aluminum tube 4 inches in dia. . the end caps are held on with 8-32 screws and sealed with rubber o rings . your planning on running this at 50-100psi?


Yes I’m planning on 50!psior less. They said 20 would run the engine but I don’t think there will be much torque.  I’ll have an air compressor to start with I think  we’ll see hot the heat works. I spilled a full glass of water on my notes and sketches so I’ll have to te do things agin.  I have a couple nice gears so I’ll make a gear boiler fill pump out of them . My son and I talked a both this to day . I got a tooth belt and pulley drive today. Now I need to make this into a gear down to make sure the engine can run the generator to drive the water pump . I think there is a 3:1 reduction plus enough to double that if necessary. I would like to keep  engine around 1,000 rpm I think it will go faster but I done want to break anything right away. The stepper motor generators may take more power than I thought the turbine needs a gear reduction too so I need to do some thinking on it. I don’t have any idea how it will work out already heard of one wrecked. The little one will be more noise maker than very productive it will go about a jillion rpm  but I don’t have hopes of any torque.
Byron


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## Bentwings (Jan 20, 2022)

Bentwings said:


> Yes I’m planning on 50 psi or  less. They said 20 would run the engine but I don’t think there will be much torque.  I’ll have an air compressor to start with I think  we’ll see how that heat works. I spilled a full glass of water on my notes and sketches so I’ll have to te do things agin.  I have a couple nice gears so I’ll make a gear boiler fill pump out of them . My son and I talked a about this to day . I got a tooth belt and pulley drive today. Now I need to make this into a gear down to make sure the engine can run the generator to drive the water pump . I think there is a 3:1 reduction plus enough to double that if necessary. I would like to keep  engine around 1,000 rpm I think it will go faster but I done want to break anything right away. The stepper motor generators may take more power than I thought the turbine needs a gear reduction too so I need to do some thinking on it. I don’t have any idea how it will work out already heard of one wrecked. The little one will be more noise maker than very productive it will go about a jillion rpm  but I don’t have hopes of any torque.
> Byron


Yes that’s correct the 8-32 button head screws will go in from the out side like a RR boiler there is also a 3/8” dia stainless steel tie rod from one end cap to the other with 2/4 28 unf  gr 8 bolt through the end caps to provide extra end cap anti blow out . The o rings will be Teflon rather than rubber I think final assembly will have high temp silicone sealer around the perimeter of the end cap.  Due to thermo expansion it’s possible the o rings might leak but it’s the same material as the pistons have for piston rings.
My hunt and peck targeting was not good on my first post. Spell check does unusual things some times and I miss letters some times as I see two of each which one to poke at sometimes is a dead miss good thing I’m not a sniper. LOL I don’t  THINK THE END CAPS WILL FLEX MUCH As they WILL BE 1/2” thick aluminum dome shape  I may use an end gasket or o ring there is not much land area so I may create a groove with an internal groove seal if if 1/4 wall tube was available I’d have used it and there would have been room for an end face o ring seal I know this sounds complicated and I have not finished re drawing my ruined sketches. Fortunately my son understands what I’m planning actually I think the 8-32 screws are the weak point  due to thermal expansion. They may be subject to loosening so I’ll be sure to check them as things progress. I’ll know more over the week end as things progress. I just wish I could be there making chips myself instead of being here  watching the thermometer fall -10 F now going down to -15 by morning . Hopefully engine will arrive on schedule

Byron


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## Steamchick (Jan 21, 2022)

Hi Byron, You sound to be very productive with your ideas. Just a couple I want to debate:

If you are planning on just balsa wood for insulation, that will be all you need for conductive losses, if around 1/2" or more. So I can't see any reason for the car exhaust stuff? But your choice. However, you should consider radiation losses (the radiant heat shines straight through the balsa or other until it hits the stainless steel). So if you polish the aluminium tube that will be excellent, or wrap in aluminium foil. Either will reduce radiant losses significantly compared to doing nothing with the surface of the tube.
My biggest issue is the use of aluminium with steam. I thought this was always a "NO! NO!" because water doesn't corrode aluminium rapidly, yet STEAM does, especially at elevated temperature. And when it does it gives off hydrogen, which has the potential of being very explosive... So although domestic pressure cookers with steam at up to 15psi exist and are safe to use, please check what higher temperature steam will do to your boiler.
A quick check suggests you need >5.2kW of steam to extract if the engine needs 50psi at1000rpm (and a generator to load the engine). Of course, at 20psi you'll only need 3kW... of steam power. Allowing for losses (maybe a couple of hundred W if well lagged?) you'll need more than those figures from the heaters. Unless I have screwed-up the calculations? (I had to correct some glitches in my spreadsheet). What did you calculate?
What "penetrations" will you make in the outer shell cylinder? (If any?) I can see a design where all the safety valves, water gauge connections, steam extraction, water-feed, etc. is done via the end plates, so the boiler shell is "without penetrations". but that is unusual. Mostly there is a steam dome (to collect steam high above the spraying surface of water), water feed, connection for safety valve, etc. so that affects the hoop stress calculations and comparison of the design with permissible safety limits. ASME uses a "Standard" value of 3.3 for the SCF if ANY penetrations exist in a boiler shell or tube. With this SCF (assuming at least 1 penetration) for your boiler at 50psi, I get a hoop stress of 1902psi and I think the permissible stress will only be 1141psi for aluminium..? which I reckon is a FOS of less than 5. But the regulations normally require a FOS of 8? But I may be wrong? If there are no penetrations in the shell tube, then the FOS is over 15 - which is good. - What have you calculated? - I am keen to be sure my calcs are sensible, and if you have close results I'll be happy.
Thanks,
K2


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## Bentwings (Jan 21, 2022)

Steamchick said:


> Hi Byron, You sound to be very productive with your ideas. Just a couple I want to debate:
> 
> If you are planning on just balsa wood for insulation, that will be all you need for conductive losses, if around 1/2" or more. So I can't see any reason for the car exhaust stuff? But your choice. However, you should consider radiation losses (the radiant heat shines straight through the balsa or other until it hits the stainless steel). So if you polish the aluminium tube that will be excellent, or wrap in aluminium foil. Either will reduce radiant losses significantly compared to doing nothing with the surface of the tube.
> My biggest issue is the use of aluminium with steam. I thought this was always a "NO! NO!" because water doesn't corrode aluminium rapidly, yet STEAM does, especially at elevated temperature. And when it does it gives off hydrogen, which has the potential of being very explosive... So although domestic pressure cookers with steam at up to 15psi exist and are safe to use, please check what higher temperature steam will do to your boiler.
> ...


as I noted I spilled a full glass of water on my entire pile of notes. I had a big mess of drying papers of course the super fine black marrrs I used sonic an readily see are now some kind of artwork don’t laugh too hard my kitty was running all over probably thinking I was sbout to explode. So I’m rebuilding the mess the aluminum is quite strong enough when you consider water pressure is around 45-50 psi in RV WATER TANKS THAT ARE PRETTY THIN WALLED AN INEXPERIENCED GUY ONCE BLEW ONE UP WITH 120 psi air very lucky nobody got hurt. It was a 5?gallon tank . I have no idea what he was doing testing with shop air . I did some basic stress calculation observing that the screws holding the end caps in might subject the end of the main tube to to a testing effect which is where overlapping plates you see in bridge construction comes from.  By using the through to tod I was able to load its bolts in tension preventing any real bending ofvthe end cap which is unlikely anyway we often lift race care engine with a 4 bolt plate on the carb studs. These are 1/4 inch to 5/16” engines  can weigh 1,000 pounds And I’ve never seen any of these bolts pull out or break the lifting plates are often just loosely held on with hand installed nuts so the things are poorly mounted  a 1/4” gr 8 bolt is amazingly  strong so I’m pretty confident ther won’t be issues there are no closed copper tubes so collapse as you pointed out won’t happen they are the just to help circulation and provide heating surface area. As far as heater go they are stainless tubes surrounding the elements . I don’t have a way of measuring wall thickness but I have to go with previous experience here the same things were used to heat platic mold in molding  while not submerged or pressurized at lest not measurable I don’t see any problems . I know it seems like a low heating capacity and I may be taken to task here we will se . This boiler holds less than 3/4 gallon subtracting volumes of all the submerged parts there just it’s is not a lot of water in it which is why I need to come up with a good fill pump . I have the parts to do it I just have not got that far yet . It’s hard to believe how fast and how far this hobby has advanced for me . I “0” when I made the decision yet 50+ years of model airplanes and who bows how many years in sports  I played senior base ball untill I was 72   And of course my life career. I appreciate any challenges and comments . I consider them learning experiences. Every spect of this hobby is new and bears investigating . I’m trying to document things I do if for no reason other than have w page to look at and say yep I considered that and here is what I did . When you say hey you need to calculate this or that , I most certainly will look into it . Because it’s part of learning sbout this hobby. I’m building on your experiences. As I noted I’m open to debate and out right challenges 
I’m just having a good time already . Sorry I got carried away. I have an INT blood yet so I must go for now . The engine is supposed to be delivered today I just checked tracking and it’s out for delivery .  I’ll get back later thanks

byton


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## Steamchick (Jan 21, 2022)

Aha! - the wonders of Google! It seems that corrosion of aluminium in steam is a real problem at 400C. but maybe at 200C you'll be OK?
CORROSION OF ALUMINUM AND ITS ALLOYS IN SUPERHEATED STEAM (Technical Report) | OSTI.GOV 
K2


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## Steamchick (Jan 21, 2022)

Hi Byron,
Perhaps I have mis-understood something. Can you supply overall dimensions of this 3/4gallon boiler?
I had read 44" diameter as 4" diameter - as you suggest you sometimes double poke characters and spell checker can't spot the error. So is it 44" diameter? Seems wrong for 3/4 gallon? I assume you are on "USA short gallons of 5 pints" (or something?) so 3/4 gallon volume of boiler would only be 3.75pints, or 108.3cu.in. On 4" diameter, this would be 8 1/2 in long. On a 44" diameter this would be 0.3" long... But then you talk about RV tanks and things and I wondered if you were planning on a 44" diameter boiler after all?

Dan, you suggested links to UK code information, but unfortunately I can't get it to link to anything:



Dan Rowe said:


> _ I found the answer to my question about UK boiler code at the end firebird's small boiler thread reply #395 by SandyC. Home Model Engine Machinist Forum
> Here is another good thread about UK boiler rules._
> _http://www.homemodelenginemachinist.com/index.php?topic=1886.0_
> _Cheers Dan _


Any chance you can add an internet link more directly to the UK codes?

Thanks, K2


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## Bentwings (Jan 21, 2022)

Steamchick said:


> Aha! - the wonders of Google! It seems that corrosion of aluminium in steam is a real problem at 400C. but maybe at 200C you'll be OK?
> CORROSION OF ALUMINUM AND ITS ALLOYS IN SUPERHEATED STEAM (Technical Report) | OSTI.GOV
> K2


I did forget to note regarding corrosion. Being a cruise boater I’m well aware of marine corrosion . To that end I have a screw in anode exactly as was used on my cruiser also I have two magnesium rods I can make into more or longer anodes. I don’t like machining magnesium where steel is machined as it it means extreme clean up measures. So I’ll keep it to a minimum and just order an additional anod it’s a npt thread so not a real issue but just another hole to fill .
I had thought about a steam dome but I think I’ll just use a manifold and keep the holes to a minimum in the boiler the engine has more or less built in intake and exhaust ports  so I don’t think there will be much of an issue there . The med INR is done . What a wonderful way to get around clinic visits . The nurse come right to my door bringing her kit in so I have my own clinic. Even doc visits are now in home, just like the old days. It’s an incredible thing as I don’t have to depend on anyone to drag me around. There also is a med bus I can take if necessary but it’s much more inconvenient. Once I get he Evike conversion done in the spring I can ride to any clinic visits necessary .those will be few. UPS  engine delivery is still on schedule  up to 9 PM.  I had one of those a couple days ago  

I tried to get som ammonia today Walmart is out cub foods is out local grocery store is out. Even local Walgreens is out so I ordered from Amazon  sticker shock  I used to get a bottle for under a dollar at grocery store $9 now including shipping even with additional items to bring the value up for free shipping I may just put water in bath tub and let the balsa soak over night it doesn’t work as well but if I’m carefull I think ITV will bend with out cracking . Super glue fixes it easy enough however. I still haven’t gotten over $50 for a tap and die plus shipping
In reviewing heaters since there will be holes for both sizes I’m going to order another  big heater and use both . Since I’ll use two separate circuits in the house I think I’ll be ok 

thanks for the comment on the header wrap I’ll delete that I don’t like it anyway works on cars but leave it in the car shop . Hanks to internet search it confirmed that I’ll have about 5/8 gallon of water in the boiler the copper tubes and bulk heads are only a couple ounce of water as I thinned the bulkheads up to a minimum I may add an over all  length just to give a bit more volume it will be easier to do it now than later.
When we cut the tube length I’ll polish  it to reduce the micro surface area so it will radiate less heat . It’s surprisingvwhatvsurfacecfinish Does 

byron

Byron


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## Steamchick (Jan 21, 2022)

Hi Byron, will the boiler be a vertical cylinder, or horizontal cylinder? You'll need a good 1" between the highest water level and the hole for steam take-off. So for your size of boiler the vertical placement gives a better distance from max water to steam dome. It is usual to have a perforated plate or something to catch droplets from getting into the steam stream, some sort of water-steam separator anyway in the steam dome. Wet steam jams engines! That's the main reason for post-boiler heating/drying on models. Hydraulic lock damages engines! But if you have any side penetrations in the cylindrical shell they must be properly bushed - of a design to carry all the hoop stress that can't be a hoop because of the penetration.
I am concerned that your unconventional design will miss certain necessary features that are "conventional" - because history tells us they make a better boiler.
Cheers,
K2


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## Steamchick (Jan 21, 2022)

Oh, the safety valve should connect directly to the boiler, not be stuck on a manifold.
K2


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## Bentwings (Jan 21, 2022)

Steamchick said:


> Hi Byron,
> 
> 
> Bentwings said:
> ...


im terribly sorry I completely missed that gaffe the tube  is 4” 3/16 wall tube initially 14”  long but I think  I’ll add an inch as the tube is 18” right now. 
 I have to laugh about this one the first time I got to travel to Europe we went out for dinner it’s bad enough I don’t have a second language  but we were sitting in a local pub  the waiter came to take or dinner request he asked if we would like a beer  I like a dumb American  had no idea what to ask for but a guy across from us had thi great big tall glass it was huge some places here have a yard of beer glass  similar to this so I said something like the gentleman over there has I don’t know how much it was but it lasted a whole evening. I had to watch out of the corner of my eye on how to hold the thing .  It was good we were on foot so I’m glad we were not driving .  
 Ok I’ve got to stop I’m making too many mistakes . If the engine  arrives I’ll take a picture and post later.
Byron


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## Bentwings (Jan 21, 2022)

Steamchick said:


> Hi Byron, will the boiler be a vertical cylinder, or horizontal cylinder? You'll need a good 1" between the highest water level and the hole for steam take-off. So for your size of boiler the vertical placement gives a better distance from max water to steam dome. It is usual to have a perforated plate or something to catch droplets from getting into the steam stream, some sort of water-steam separator anyway in the steam dome. Wet steam jams engines! That's the main reason for post-boiler heating/drying on models. Hydraulic lock damages engines! But if you have any side penetrations in the cylindrical shell they must be properly bushed - of a design to carry all the hoop stress that can't be a hoop because of the penetration.
> I am concerned that your unconventional design will miss certain necessary features that are "conventional" - because history tells us they make a better boiler.
> Cheers,
> K2


I didn’t see the first part above . It will be horizontal .
Byron


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## Steamchick (Jan 21, 2022)

Do you have a sketch/drawing of how you plan all the necessary fittings?
K2


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## Bentwings (Jan 21, 2022)

Happy days are here my engine just arrived!  My kitty is helping me open the box!   It’s full of bubble wrapped parts ! It will take hours to un wrap all of them ! I see a pack of instruction and an assembly drawing and bill of materials  I think there are about 200 individual parts lots of small stuff . 
I can’t say enough for chilertern. They have been just great to work with. I get nearly same day response from emails  I was also able to call directly it would have been a horribly expensive call except for AT&T set up unlimited over seas calls for $15 per month that I can end by just calling them  so far I can’t complain about anything  even my bank cooperated and released fun’s as requested. No charge
Back to checking thing out

Byron


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## Bentwings (Jan 21, 2022)

Steamchick said:


> Do you have a sketch/drawing of how you plan all the necessary fittings?
> K2


That’s pretty close I have Teflon o rings or deed as well as Rodman o ring that ar softer .


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## Bentwings (Jan 21, 2022)

I carefully read this over then posted it now I see errors that weren’t there


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## Bentwings (Jan 21, 2022)

Bentwings said:


> I carefully read this over then posted it now I see errors that weren’t there


Ok m bluish hoizntal I’ve added an inch so it needs 15” long 4” of 3/26” wall . I don’t have a steam dome per se as this in my mind would be either weld on or bolt on I really don’t vent to weld as first I’d have to crate shape then welding right in the middle of the tube I think would create a weak spot. It’s 6061 t6 aluminum but welds almost invariably creat a weaker area . That’s why I also elected to make a bolt together assembly bolt on means more holes to leak in my mind I’m not worried about pullout  I had planned to have the boiler sit with one nd slightly higher than the o the so a high point to take steam out. The blow down or cylinder cleaner was something I had a question about. My very early trace was behind various steam engines yes I’m that old  I often wondered why there was a huge blast of steam right before the train started moving  I do know about hydraulic lock from auto racing saw it a fe times we never had issues . The hemi engines have the exhaust ports low on the heads so simply baring the engine over in reverse rotation automatically cleared cylinders . Today’s top fuel dragsters ar very near hydra lock just because of the enormous amount of fuel that goes into them, some time a cylinder misfires so the fuel doesn’t ignite  then you see the big fireball as parts go flying  we burned a lot of pistons but never hydra locked a motor .  So I need to maybe know some tech on how to plumb a blow down Ipipe I might even be into a solenoid operated one just to keep fingers out of the way. I’ll have a filter luberacator pressure gage  like an air compressor has at this point. I was thinking about sort of dehumidifying the steam. But I can see how condensation could get in and cause issues . I just got my steam engine kit today . It has some kind of intake manifold to use auto terms, in fact two as it’s really two engines connected together I’m a little concerned about timing as I did not see anyting in the assembly instructions . I haven’t un wrapped all the parts yet . There are a lot of them . I thought there might be some kind of drain in the manifolds I may have  create one or two . As I get more into the assembly I’ll know more . There are some castings I’d like painted  so I’ll dig them out tomorrow .  I can see I’ll need an aluminum mounting plate to keep everything in alignment  that’s not an issue  I have Lenny of aluminum  platsaround I really did not want to hard this I not a very big engine I’m guessing but 6”x6” line the piping as it always seems to get ugly bends in te wrong places but I may have to compromise . I’ll just make a spare set of lines if necessary .  We have flaring tools to do about anything required. I was goingvto use AN 3 or 4 fittings but I think they will be too big and as pretty color as they are I ghnkbtheyvwill clutter it up . It’s getting harder to keep up with typing almost like saying … time to post and answere questions later. I’ve had issues where the spell check tries to out guess me and inserts it’s own words  even if I preview which I do but this dumb vision issue bites me occasionally 
Buron


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## Bentwings (Jan 21, 2022)

Bentwings said:


> Ok m bluish hoizntal I’ve added an inch so it needs 15” long 4” of 3/26” wall . I don’t have a steam dome per se as this in my mind would be either weld on or bolt on I really don’t vent to weld as first I’d have to crate shape then welding right in the middle of the tube I think would create a weak spot. It’s 6061 t6 aluminum but welds almost invariably creat a weaker area . That’s why I also elected to make a bolt together assembly bolt on means more holes to leak in my mind I’m not worried about pullout  I had planned to have the boiler sit with one nd slightly higher than the o the so a high point to take steam out. The blow down or cylinder cleaner was something I had a question about. My very early trace was behind various steam engines yes I’m that old  I often wondered why there was a huge blast of steam right before the train started moving  I do know about hydraulic lock from auto racing saw it a fe times we never had issues . The hemi engines have the exhaust ports low on the heads so simply baring the engine over in reverse rotation automatically cleared cylinders . Today’s top fuel dragsters ar very near hydra lock just because of the enormous amount of fuel that goes into them, some time a cylinder misfires so the fuel doesn’t ignite  then you see the big fireball as parts go flying  we burned a lot of pistons but never hydra locked a motor .  So I need to maybe know some tech on how to plumb a blow down Ipipe I might even be into a solenoid operated one just to keep fingers out of the way. I’ll have a filter luberacator pressure gage  like an air compressor has at this point. I was thinking about sort of dehumidifying the steam. But I can see how condensation could get in and cause issues . I just got my steam engine kit today . It has some kind of intake manifold to use auto terms, in fact two as it’s really two engines connected together I’m a little concerned about timing as I did not see anyting in the assembly instructions . I haven’t un wrapped all the parts yet . There are a lot of them . I thought there might be some kind of drain in the manifolds I may have  create one or two . As I get more into the assembly I’ll know more . There are some castings I’d like painted  so I’ll dig them out tomorrow .  I can see I’ll need an aluminum mounting plate to keep everything in alignment  that’s not an issue  I have Lenny of aluminum  platsaround I really did not want to hard this I not a very big engine I’m guessing but 6”x6” line the piping as it always seems to get ugly bends in te wrong places but I may have to compromise . I’ll just make a spare set of lines if necessary .  We have flaring tools to do about anything required. I was goingvto use AN 3 or 4 fittings but I think they will be too big and as pretty color as they are I ghnkbtheyvwill clutter it up . It’s getting harder to keep up with typing almost like saying … time to post and answere questions later. I’ve had issues where the spell check tries to out guess me and inserts it’s own words  even if I preview which I do but this dumb vision issue bites me occasiona



I do appreciate note and comments .  
Byron


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## Bentwings (Jan 22, 2022)

Bentwings said:


> I do appreciate note and comments .
> Byron


I’m really frustrated. I carefully reviewed my my last post, made a couple corrections  then posted.  The phone spell check do its own thing and built in words I never put in and messed up he context . I though I missed a couple words but it was correct when I hit the post button . It’s bad enough I have my own issues, I don’t need extra issues . I’ll search and see if there is some way to either disable this or get around it. 
byron


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## Bentwings (Jan 22, 2022)

Bentwings said:


> I’m really frustrated. I carefully reviewed my my last post, made a couple corrections  then posted.  The phone spell check do its own thing and built in words I never put in and messed up he context . I though I missed a couple words but it was correct when I hit the post button . It’s bad enough I have my own issues, I don’t need extra issues . I’ll search and see if there is some way to either disable this or get around it.
> byron


I checked on micro soft and it did the same thing on the post to them . I left them with screw it , you figure it out , get back to me when you have an answers I can even read . I even Ickes out a new stylus washed screens even my hands and fingers .  Even ordering on Amazon or directly from suppliers there is this issue . I’ve called Amazon I now just call suppliers directly if I can . I’ve even returned things I didn’t order or received incorrectly. Sometimes it even misspells my name at the end of posts 

buron


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## Bentwings (Jan 22, 2022)

Bentwings said:


> I checked on micro soft and it did the same thing on the post to them . I left them with screw it , you figure it out , get back to me when you have an answers I can even read . I even Ickes out a new stylus washed screens even my hands and fingers .  Even ordering on Amazon or directly from suppliers there is this issue . I’ve called Amazon I now just call suppliers directly if I can . I’ve even returned things I didn’t order or received incorrectly. Sometimes it even misspells my name at the end of posts
> 
> buron


I read every comment and I really appreciate them . I try to answer questions, explain my thoughts but this spell checker is frustrating 
. I got good grades in English even Latin I even tested out of a full two years of engineering composition in college . This mess makes me look like someone from Tim buck two . See it can’t even post what I entered  . Today I’m goingvto attempt to make some sketches or try and wade through dome cad  I may be able to make it work. My late son changed some things that realy should have been left alone so please bear with me . I’ll tr and get back after I cool off. Open the blow down valve I guess it’s called by steamersLOL


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## Bentwings (Jan 22, 2022)

Bentwings said:


> I read every comment and I really appreciate them . I try to answer questions, explain my thoughts but this spell checker is frustrating
> . I got good grades in English even Latin I even tested out of a full two years of engineering composition in college . This mess makes me look like someone from Tim buck two . See it can’t even post what I entered  . Today I’m goingvto attempt to make some sketches or try and wade through dome cad  I may be able to make it work. My late son changed some things that realy should have been left alone so please bear with me . I’ll tr and get back after I cool off. Open the blow down valve I guess it’s called by steamersLOL


I came about the same as far as heater required. I just ordered another 1200 watt heater soninyinkninmay be marginal but ok it will be a trill error I can get higher wattage if necessary that will fit in the same NOT fitting hole I’ve allowed . Most fittings will be 1/8” NPT with bushings or adaptors for what ever else is needed at this point I see only the fill Port used by the gear ump and the exit port on top to a manifold block for other distribution. There may be ports for  the level gage which I don’t have yet  and a rapid drain on the end.  I ran into a condensor or economizer  which I have given thought to. I’m not sure just waist is needs nor how much is needed for this small system  I was hoping the little turbine might act like a centrifugal air cleaner I have thoughts to a filter of sorts but I don’t know how much exhaust will be generated . I’d like not to have oil air all over the place . So maybe some suggestions .  There were turbo air cleaners in the textile industry that were very efficient . I don’t see anything as complex as industrial things. It will be interesting to see how hot th exhaust is.

on a side note the balsa wrap is nt going well the first 1/8” pice I started on last night is water logged but not forming around the tube well  this is where the ammonia worked in the past but I won’t see the stuff for several days .  I forgot the anode ports one on each end I found two more magnesium anodes from he boat today

this boiler has evolved into a quite complex thing . But electric heating I think made it more difficult . My son is cutting chips today

the engine have about 200 icees counting nuts as bold many as pretty small. I haven’t un packed all of it ye as I want to paint he frames before I start assembly it will be a gray barbecue type color I think . Textile equipment was the most horrible green ever created . I won’t be sad if I never see it again. LOL I HACE A SET UP BAD PLUS AN aluminum mount board . I’m thinking I at soft mount he engine frames both are linked by th man flywheel . I may have t switch to a flexible cpling but ubtill I have both assembles completed I won’t be there is an outer shaft support but I have a self aligning ball bearing for that as well as aluminum material I have one extra flywheel but it needs a little polishing to finish it up .
Now I have company coming next week so I’ll hac t go into idle mode 

byron


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## Bentwings (Jan 23, 2022)

Steamchick said:


> Hi Byron, You sound to be very productive with your ideas. Just a couple I want to debate:
> 
> If you are planning on just balsa wood for insulation, that will be all you need for conductive losses, if around 1/2" or more. So I can't see any reason for the car exhaust stuff? But your choice. However, you should consider radiation losses (the radiant heat shines straight through the balsa or other until it hits the stainless steel). So if you polish the aluminium tube that will be excellent, or wrap in aluminium foil. Either will reduce radiant losses significantly compared to doing nothing with the surface of the tube.
> My biggest issue is the use of aluminium with steam. I thought this was always a "NO! NO!" because water doesn't corrode aluminium rapidly, yet STEAM does, especially at elevated temperature. And when it does it gives off hydrogen, which has the potential of being very explosive... So although domestic pressure cookers with steam at up to 15psi exist and are safe to use, please check what higher temperature steam will do to your boiler.
> ...


ok so the balsa will work . I have exactly 1/2” of material I’m working on wrapping . I’ll polish the basic tube then add balsa. I think the polished stainless exterior will make it relatively cool . I haven’t come up with an idea fore the end caps other than some fancy carving . I have som blocks of balsa and I think I could show my boys how to do some metal spinning. For outer covering . Ther will be some exits in th ends but I can mold th cutouts if necessary in balsa I actually was thinking of a singbopen insulated door . We do these hatches a lot on the Rc planes so it won’t be hard . It would give better access to fittings . Maybe clean up the ugly mess that a bunch of fittings can make . As far as calculations I have to admit I took the easy way and looked up various calculators on line. I don’t think I can get a factor of 8 that seems to be floating around. The extra tie rod between the end cap will go a long way toward keeping the end caps on I’m more concerned about the changes in temp causing loose screws around the periphery that hold the end caps. As I recall this would create a bending moment that could cause the screws to want to yer out . I simply have not experienced this. I don’t have the neat analysis program anymore that would clearly show this  the couple of lithium military batteries explosions where the end cap failed actually tore the stainless steel or titanium shell apart . These were some really high pressure  in the 10’s of k’psi . Hydraulic testing only showed potential cracking or leaks these were pyrotechnics gas generators so pressures got high very quickly  then the electrolytes detonated . As we used to say the batteries were as powerfull as the odenance.  Nice I get the steamer assembled I’ll have a better idea of pressure required I may be grossly under estimating but this little engine, actually a pair linked together just don’t have the crankshafts with enough stroke or bores to produce enormous torque the crankshafts just aren’t bug enough to handle big loads  and I’d like to limit rpm  to12-15,00 just so it lives a comfortable life . I may be all wet here . My usual thing is to squeeze every bit out but  bad enough the turbine will be capable of 50k . I’m already concerned about lube for it.
As far as corrosion I was not aware that hot steam made it much worse I do have magnesium anodes from my boat  marine corrosion in is always a headache but if anodes are replaced on time it’s easy to control I never had issues on the water .  Working in the dairy with live steam cleaning I don’t remember any issues stainless steels seemed to be clean and shiny all the time  Steel milk crates rotted out easily . I suppose it could be said “he will learn the hard way “ I see lots of learning coming . I do appreciate comments I dug up some old school drafting stuff so I’m going to  try and improve my sketches.  I just got my new building board so I can have a mini drawing table for a while 
Byron


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## Bentwings (Jan 23, 2022)

Bentwings said:


> ok so the balsa will work . I have exactly 1/2” of material I’m working on wrapping . I’ll polish the basic tube then add balsa. I think the polished stainless exterior will make it relatively cool . I haven’t come up with an idea fore the end caps other than some fancy carving . I have som blocks of balsa and I think I could show my boys how to do some metal spinning. For outer covering . Ther will be some exits in th ends but I can mold th cutouts if necessary in balsa I actually was thinking of a singbopen insulated door . We do these hatches a lot on the Rc planes so it won’t be hard . It would give better access to fittings . Maybe clean up the ugly mess that a bunch of fittings can make . As far as calculations I have to admit I took the easy way and looked up various calculators on line. I don’t think I can get a factor of 8 that seems to be floating around. The extra tie rod between the end cap will go a long way toward keeping the end caps on I’m more concerned about the changes in temp causing loose screws around the periphery that hold the end caps. As I recall this would create a bending moment that could cause the screws to want to yer out . I simply have not experienced this. I don’t have the neat analysis program anymore that would clearly show this  the couple of lithium military batteries explosions where the end cap failed actually tore the stainless steel or titanium shell apart . These were some really high pressure  in the 10’s of k’psi . Hydraulic testing only showed potential cracking or leaks these were pyrotechnics gas generators so pressures got high very quickly  then the electrolytes detonated . As we used to say the batteries were as powerfull as the odenance.  Nice I get the steamer assembled I’ll have a better idea of pressure required I may be grossly under estimating but this little engine, actually a pair linked together just don’t have the crankshafts with enough stroke or bores to produce enormous torque the crankshafts just aren’t bug enough to handle big loads  and I’d like to limit rpm  to12-15,00 just so it lives a comfortable life . I may be all wet here . My usual thing is to squeeze every bit out but  bad enough the turbine will be capable of 50k . I’m already concerned about lube for it.
> As far as corrosion I was not aware that hot steam made it much worse I do have magnesium anodes from my boat  marine corrosion in is always a headache but if anodes are replaced on time it’s easy to control I never had issues on the water .  Working in the dairy with live steam cleaning I don’t remember any issues stainless steels seemed to be clean and shiny all the time  Steel milk crates rotted out easily . I suppose it could be said “he will learn the hard way “ I see lots of learning coming . I do appreciate comments I dug up some old school drafting stuff so I’m going to  try and improve my sketches.  I just got my new building board so I can have a mini drawing table for a while
> Byron


I had seen an old horizontal boiler at a textile factory . It wasn’t operational but it kinda influenced me also trying steamers are horizontal, at lest I not seen a verticals . Plenty  tall stacks 
So that’s wehrrewhat the idea came from there was also a icture of the mill steamer fromthe late 1800’s so that’s why I chose this one . Nostalgia I guess since I made a massive motor driven rolling mill with some electric motors probably off and old battle ship. They had US NAVY stensiled on them 40+ hp  they had som big copper power cables . So one of my driven things is a “dyna mo  “ that actually looks a lot like these giants I don’t have any lans to duplicate or even simulate any textile stuff other than a piece of history it was a dark age for me . Sad  
As many fittings as possible will be in the end caps one end will have the level gage and fill port, the opposite end will have the fast blow downs port for steam out to a distribution manifold  I’ll have to give into a port for pressure relief on the high end maybe teed to the fast blow down. I don’t know yet ., ossibly the pressure gage gotta have a whistle some place too . I’m thinking the manifold will cover a lot of ground providing ports for anything needed I’m not sure where the steam feed goes yet. I haven’t unpacked all the parts yet the engine mounting hole are very small about 3 mm to my un metricized  eye  I tried to get the big computer up but it takes a double monitor so I’ll have to un pack that then try again . This was my Ltd big gaming center so it’s loaded with  games and big monitors I didn’t get to see how it was it together so I’m fumbling around even the laptop has big processor and external monitor hookup so I’m still stuck with iPhone and iPad  I’ve got to wat for he pantdcasting before  I can really get started on the engines 

byron


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## Bentwings (Jan 26, 2022)

I’ve had some real issues posting so I’m switching devices in hopes that things can be easier for me. 
so I got ammonia and did a test to compare with plain war. The second test sheet of balsa is now drying. It will most likely be ready lat today. Already it was much easier to ven just get started bending.I use dot water adding Amina. About 5050 mix. Very strong. But it wrapped pretty easily. Looking at how the edges of the sheet fit e tube when dry.  Ultimately I don’t think this Elle an issue.the hardest part onfar is just getting set up as in didn’t have enough heavy rubber bands. I was going to just pull duct tape. Around it but the wet just messed it up miserably. Once I get all the material at least pre shaped I think. I can make a vial nice smooth transition. . Remains to be seen however.   I’m. Curious just how hot the bals will et so I’ll be documenting that on start up. I expect a gap at the top it I have a thick strip icanuse as filler if needed. D lik to keep as few endings or fitting off the top. There will probably be a fill port and an exit  port. It to go to distribution block wihvaious outlets as needed. I did see some oe had warden the tubes and fittings. I remember seeing. This in the kid boiler room at the dairy. so some ideas  might beelpfull. . I remember a project where else coping o different diameter tubes were bent together. It was a messy project. I remember. I do have bonding tools available so may try it.  Some industrial units have the pipes enclosed in an insulated box. . Not very excited about that. Sketches and drawings. Well I managed to spill water all over what I. And twice.  Fortunately my son has my original sketch and is cutting Thea in tube and he understands how I planned the end Capps and bulkheads for the water tubes. O it’s in process.  I’m hoping to give him the engine castings for painting shortly. Then Ican start engine assembly. Th are two complete engines joined in the middl. I did heck the crankshafts last night. They are joined by a longer flywheel hub.  I don’t really like this but I didn’t design it and I have to ghinkts been around for a while so proven. There are nice fox coplings available too. Also found I gear couplings like eebuse on yhe race cars.  So coupling is not a big deal.. one ngine has the outer shaf hanging in the breeze, so I have a self alighting ball bearing planned mounted in a support. This will give a solid support for drive belts.   There  are. Plenty of main bearing supports on the castings.  Basic test shows these to e.  Very well done as both cranks run true. And the joining flywheel slides in perfectly. Providing a quite rigid connection.


 I don’t have a good way to Maureen output torque yet. I think it can be calculated based on output from te dynamo or generators I need to get some tech. Myself here.  May have to gage a small scale and rig up a mini Dyno.
I did get a prurient relief valve so as soo ss I can get out o the sho. I’ll test it and git info on heat the springs can do and see if I make some adjustment with shimsts exactly like our fuel injection relief valves  and even has a atching thread .  There will be a blow down line and valve.. 

the two turbine will be separate from the engines.


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## Bentwings (Jan 26, 2022)

I really sorry. This spell check just won’t leave me alone.
im going tontybagai.

the dimensions are. 1” long 4”d tube 6061 t6;aluminum 3/6” wall thickness. End caps 6061-t 6 aluminum. 1/2” basic thickness . They will have a dome shape repained by 8 832 button head hex drve stainless steel screws..10 1/2” of water. tubes. 1/4” bulkhead mounts internally. Two 1100 watt electric heaters.  Boiler to rest on supports so
one end is about 1 /2” higher. This canchange as needed. 1/2” balsa  insulation.  Oiler tube to. Be polished. Thin polished stainless steel outer wrap. Decoration.   Minimum fittings on top. water llevel gage on one end.. blow own valve on high end. exit steam into hex distribution block. 1/8” NPT fittings a much as possible. Engine has 1 /4” 40 tpi ME  fittings. tap and die ordered. Pressure gage and siphon tube. Gear fill pump. Teflon rings with ptfe softer option.

there is a 3/8” tie rod between end caps with1/4-20 Socket head cap screw in  each end cap.this is to prevent end cap blow out.  Even with a different device it’s being painful. If I missed something please just ask and I’ll y and respond better.


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## Bentwings (Jan 27, 2022)

Thanks or the heads up o the pressure relief valve position. I can easily tap a fitting hole for it on top of the boiler so that here it will go.  I’ve already blown $50 on a tiny 1/4” 40 tpi ME tap and die so another $50 for one mor size  wot hurt too much between al 4 pieces they will b only slightly heavier than the pen that I filled out t the order form. LOL. SAD. humor  parts hould be going out for painting today. I gave my son some ideas for a drill and tap guide o e said he would make up something. Lack of mobility is o frurating.  . I still need to consider some valves.  Gllobevalves seem traditional. I have found some Teflon ball valves that might work.  . The next thing that just came up is the. steam exhaust. . I found there are condensers. In fact cilternrn makes one.  I had thought that maybe one of the turbines could act as a centrifugal device to separate oil water and air . This so thoughts would be welcome. I can see some kind of reservoir.   I have an extra  airline filter I could also use. Industrial  ones are very complicated. I think they are called economiseers .  I’m not  sure  how they work either. I don’t have one on my hot water heater at home.
I still have not found much in small diameter gages. Automotive stuff I usually 2 1/16” . They can take up huge  amount of room that I’d really rathernot do.the cost of them is out of sight. There are cheap ones too but ugly and lacking durability.  His little reissue really not very big and I like not to have to double the footprint  just  for gages.

byron


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## ChazzC (Jan 28, 2022)

Bentwings said:


> Thanks or the heads up o the pressure relief valve position. I can easily tap a fitting hole for it on top of the boiler so that here it will go.  I’ve already blown $50 on a tiny 1/4” 40 tpi ME tap and die so another $50 for one mor size  wot hurt too much between al 4 pieces they will b only slightly heavier than the pen that I filled out t the order form. LOL. SAD. humor  parts hould be going out for painting today. I gave my son some ideas for a drill and tap guide o e said he would make up something. Lack of mobility is o frurating.  . I still need to consider some valves.  Gllobevalves seem traditional. I have found some Teflon ball valves that might work.  . The next thing that just came up is the. steam exhaust. . I found there are condensers. In fact cilternrn makes one.  I had thought that maybe one of the turbines could act as a centrifugal device to separate oil water and air . This so thoughts would be welcome. I can see some kind of reservoir.   I have an extra  airline filter I could also use. Industrial  ones are very complicated. I think they are called economiseers .  I’m not  sure  how they work either. I don’t have one on my hot water heater at home.
> I still have not found much in small diameter gages. Automotive stuff I usually 2 1/16” . They can take up huge  amount of room that I’d really rathernot do.the cost of them is out of sight. There are cheap ones too but ugly and lacking durability.  His little reissue really not very big and I like not to have to double the footprint  just  for gages.
> 
> byron



Byron,

Don't know where you have been doing your shopping, but eBay has numerous listings for HSS 1/4-40 tap & die sets for less than $20 delivered; yes, mostly Chinese manufacture and many shipped from China, but several located within the U.S. No 1/16"-27 pipe tap & die sets in the U.S., but many taps and dies sold separately, with a total cost of around $20. Amazon also has taps & dies in this cost range, with free shipping for Prime.

In my experience, Chinese and Indian tooling is good quality, and the average delivery time has been about 2 weeks (it's taken USPS that long to get a 1st class package rate small envelope from Long Island to Hershey).


Good luck with your boiler, and keep posting,


Charlie


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## chrsbrbnk (Jan 28, 2022)

Like he said quality is pretty decent just run them slow and make sure they are highspeed steel


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## Steamchick (Jan 28, 2022)

Bentwings said:


> Thanks or the heads up o the pressure relief valve position. I can easily tap a fitting hole for it on top of the boiler so that here it will go.  I’ve already blown $50 on a tiny 1/4” 40 tpi ME tap and die so another $50 for one mor size  wot hurt too much between al 4 pieces they will b only slightly heavier than the pen that I filled out t the order form. LOL. SAD. humor  parts hould be going out for painting today. I gave my son some ideas for a drill and tap guide o e said he would make up something. Lack of mobility is o frurating.  . I still need to consider some valves.  Gllobevalves seem traditional. I have found some Teflon ball valves that might work.  . The next thing that just came up is the. steam exhaust. . I found there are condensers. In fact cilternrn makes one.  I had thought that maybe one of the turbines could act as a centrifugal device to separate oil water and air . This so thoughts would be welcome. I can see some kind of reservoir.   I have an extra  airline filter I could also use. Industrial  ones are very complicated. I think they are called economiseers .  I’m not  sure  how they work either. I don’t have one on my hot water heater at home.
> I still have not found much in small diameter gages. Automotive stuff I usually 2 1/16” . They can take up huge  amount of room that I’d really rathernot do.the cost of them is out of sight. There are cheap ones too but ugly and lacking durability.  His little reissue really not very big and I like not to have to double the footprint  just  for gages.
> 
> byron


Hi Byron. Please don't just drill and tap the cylinder for the SAFELY VALVE. IT NEEDS BUSHING. The hoop stress calculations, consideration of the stress concentration factor for penetrations, etc. are all for Safety. So please get it right or don't do it at all. 
Take care, 
K2


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## Richard Hed (Jan 29, 2022)

I get a lot of my stuff here:




__





						Fractional HS Left Hand Bottoming Taps
					

Fractional HS Left Hand Bottoming Taps



					www.victornet.com


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