My first boiler

[Mechanicboy]

Use CFH 52310 Copper/Phosphorus Hard Solder, it has same color as copper. If solder between copper and bronze/brass, use flux. No flux when solder copper /copper. Easy to use copper/phosphorous hard solder.

https://www.amazon.co.uk/CFH-52310-Copper-Phosphorus-Solder/dp/B001HGP2N6

 

[Shopgeezer]

Thanks for the info. I read the spec sheets and it sounds ideal for copper and bronze/brass. I will order some and give it a try.

 

[aka9950202]

If there is zinc in the alloy don't use it on the boiler.

Cheers,

Andrew in Melbourne

 

[Shopgeezer]

Good point. I understand that zinc will cause problems in hot water/boiler applications.

 

[nealeb]

My understanding is that phosphorus-containing solders are not suitable for model boilers that are coal-fired as the sulfur from the products of combustion corrodes the solder fairly quickly (although it is presumably OK for spirit- or gas-fired boilers?) I think that the main reason that silver solder is the preferred material is that it is a capillary gap-filling material - you aim to leave a small (a few thou) gap between the parts to be joined and the silver solder will run in and form a high-strength joint. Brazing rod (brass?) does not flow so well and tends to build up a fillet which is not always so desirable. The silver solder generally has a lower melting point as well and can be obtained in a range of melting points so that there is less chance of overheating the parent material, and you can do subsequent operations with the lower melting point silver solder without upsetting the first joints. It's not unknown for people to end up melting the copper when trying to get it hot enough to melt brass - although in skilled hands this might be OK. Personally, the limited boiler construction that I have done has used silver solder and apart from the price, it is probably the best choice. But the price can be eye-watering for a big boiler!

I'm interested in the boiler illustrated at the start of this thread. Riveting (and maybe using a high-temperature soft solder for sealing purposes) is a traditional way to build a boiler although not much used for coal-fired boilers today - but how did the builder manage to rivet both the end flanged plates on a closed boiler? That's been puzzling me since I first saw the picture - it's like a "how did they get the ship in the bottle" question!

 

[Peter Twissell]

See post #4 for an explanation of the 'ship in a bottle' rivetting.

 

[nealeb]

All is explained - I follow threads via the daily digest email and it does seem to skip things sometimes by the time it's reached my inbox. Didn't see that post but thanks for pointing it out. I understand the need for rivets "just for show" - I'm in the middle of building the tender for a 5" gauge loco which will have many hundreds of rivets for absolutely no structural purpose whatsoever - purely cosmetic! The things we do for "authenticity"... In this case, the boiler in question certainly carries the air of an early prototype.

 

[Peter Twissell]

Absolutely!
When building my 3 1/2" Masie, I cut threads on a number of rivets, so I could assemble with nuts, allowing easy dismantling for access later on.

 

[terryd]

Hello my model engineering friends,
I’m finally got around to start making my first boiler, for my first build, the Stuart 10V you can see in the background. Surprisingly amount of work involved in a boiler. Starting to understand why internal combustion engines got popular.
I have no plans, just build as I go. I found it practical to start with a simple design and this “Stuart 504” style seems to be a safe bet. It´s made of a 3” copper tube. The fittings are bronze with a flange on the inside so they never will pop out. I will make all the fittings, valves and everything my selves. I´m also putting in rivets just to make it look more authentic.

I’m open for suggestions for the burner, but it has to be something that doesn’t make much noise as the gas torch type does. The engine runs so smooth, slow and quiet that it would be sad to cover that up. I´m thinking spirit burner or ceramic gas burner.

Rudy


View attachment 111145 View attachment 111146 View attachment 111147

Hi Rudy,
Did you make the middle tube a superheater as on the Stuart 504? I'd like to build a similar version as I have the cast iron endplates from a defunct Stuart 504 but no boiler.

 

[terryd]

I built the 2inch Clayton boiler just using one Sievert torch with very little insulation and it was more than capable
The drawings for the Clayton steam lorry are on the John Tom site from memory its a 1 inch bore twin the stroke eludes me
Silver solder/hard solder comes in different grades and this can be an asset when building larger boiler
Start at a higher melting one and work down the grades although Iv only ever used two. Another point is that it takes a higher temp to remelt an already made joint
Probably telling my granny how to suck eggs
cheers
frazer

Hi Frazer,

you can also protect existing soldered joints when adding others. When I took a silversmithing course we would do that by using loam made into a paste with water. I now use white correction fluid and it seems to do the job as well as the loam. I recently made a small three wick spirit burner which had a lot of soldered joints which had to be done in succession (at least 4 stages if not 5) and I only used 1 grade of silver solder in a relatively small construction. I've never had a joint fail in over nearly 50 years experience. The only time I saw silver soldered joint fail through overheating was on a Stuart 504 boiler in the aftermath of an intense garage fire (mine) and then it was just a few of the bushes and fittings which failed.

Burner ready for painting with black grate paint.

Garage fire where Stuart 504 perished (+ my complete workshop, machines, handtools and materials stock etc.)

Good job I had excellent insurance with full cover,

TerryD

 

[Rudy from Norway]

Hi Rudy,
Did you make the middle tube a superheater as on the Stuart 504? I'd like to build a similar version as I have the cast iron endplates from a defunct Stuart 504 but no boiler.

Hi Terry,
I did not make the super heater. In fact, I didn't know about it in the Stuart boiler. However, I have been playing with the thought of routing the pipe back into the fire though.
Rudy

 

[bluejets]

Cadmium bearing rods available below address in Australia,
Available in a range of melting temperatures.
Silver Solder Rods, Wires & Rings | SBA Amalgamated

 

[terryd]

Hi Terry,
I did not make the super heater. In fact, I didn't know about it in the Stuart boiler. However, I have been playing with the thought of routing the pipe back into the fire though.
Rudy

Hi Rudy.

On the Stuart 504 the middle tube is inserted into the boiler almost up to the top of the shell internally at the 'chimney' end. It then exits at the bottom and at the other end it runs back up through the shell and is soldered to the steam outlet bush where the regulator is. Thus the steam path is in the middle of the burner, superheating the steam before it exits to the regulator, unlike a lot of boilers where the superheating takes place after the steam exits the regulator. I'm not a steam engineer so I don't know which is more efficient but there must be something in it if Stuart go to such lengths to superheat the steam.

Here's a very poor sketch to try and illustrate:


TerryD

 

[terryd]

Cadmium bearing rods available below address in Australia,
Available in a range of melting temperatures.
Silver Solder Rods, Wires & Rings | SBA Amalgamated

Hi BJ,

Thanks for the link but I'd rather not breathe in poisonous metals. Silver solder is available in the UK also in a range of melting points, I've never really needed more than Easy Flo or it's modern equivalent except when making fine jewellery which I tend not to do these days but if I did I'm not sure if my assay office would accept the work for hallmarking if it contained any cadmium . I know that cadmium free is a tad more expensive due to the higher silver content but personally I think that my health is worth the extra.

Again, thanks for the thought. Stay safe,

TerryD

 

[Rudy from Norway]

Thanks for the info terryd. I have always wondered if superheated (dry) steam will be equally efficient with displacement lubricators?

 

[Rudy from Norway]

I'm nearing the completion of my boiler project. It is barely tested and operational. I stil have some work left on the burner. there is a thread here on this subject that I will attend to.

 

[terryd]

Well done Rudy, the boiler looks superb, as does the 10V. You've inspired me and I'm just starting to build mine after many years of other projects. I bought the unmachined kit some 35+ years ago with good intentions but you know, career, wife, children, motorbikes all get in the way. In fact I bought the kit when Stuart was based in Henley on Thames and it has the forged crankshaft instead of the fabricated one. I'm really looking forward to it's completion at some time in the fiture especially as due to age and health complications I have self isolated in these uncertain times so I have time for all of those unfinished projects. .

As far as a displacement lubricator is concerned I would think that as the small amount of steam enters the lubricator it will still condense while the superheated steam mainly continuse along the feed tubes. Of course as you and I know but the general public does not, the stuff generally called 'steam' which we can see is hot water vapour, steam itself is an invisible gas.

TerryD

 

[nononick]

I like your "Stuart 504" boiler. I have an original one which I bought at an auction some years ago. On mine the water tubes and steam superheater tube are on a slight slant, being a bit lower at the chimney end - something to do with better circulation I imagine. When I bought it it had the original asbestos insulation, which of course I got rid of, replacing it with soldering mat panels, from a B&Q diy store. I had to replace all the fittings on the end plate, making adaptors to fit in the larger bushes that a previous owner had installed. I am working on fitting some insulation on the exposed top part of the boiler which will be easily removable. My Stuart 10V drives a boiler feed pump where the feed pipe goes in and out of the underside of the boiler, to warm it up before it gets into the boiler itself. I have also fitted a steam manifold on top of the boiler with 4 separate valves to feed other engines mounted on the base.

Nick (in London UK)

 

[Rudy from Norway]

Nick, Thanks for info. I will play a bit whit this boiler plant before I decide if I will make a steam dryer pipe. After all, I have the condenser and why not enjoy fiddling with it.
I have the next steam engine in the planing stage so a manifold will be wanted so I can run them both.
I made the threaded parts on the boiler from bronze, so they should last. The rest of the fittings and valves are self made from bras.
Rudy

 

[Rudy from Norway]

Terry, I will encourage you to finish your 10V. I had such a pleasant time making this pretty little thing. Just looking at it after all the work makes me smile. There is something so charming about steam engines.
Another very charming engine is the Stuart twin launch, witch I will make in a slightly larger version from bar stock. Bought the plans and are in the process of making modifications and new plans.
Rudy