Seeking info

[HMEL]

Well, that's certainly interesting. I understand why it would need to be certified especially for commercial boilers, however, I would thimpfk that welding would be the very best way to make a steel boiler. Also, for small boilers, I would thimpfk pressure tests would be adequate.

I agree, but you have raised an interesting thought and that is how small a weld can be made and what would you use to keep the weld from blowing out on small materials. Time for a little research on micro welding. Using steel poses a corrosion issue that copper does not. However I have seen an industrial boiler made of stainless that was made for a brewery. And I have considered a boiler design made of steel for small hobby stuff but it would be difficult to make it look like the copper models you often see. And yes I think there is a provision in the code for certifying a pressure system with a hydraulic test. But its been awhile since I have delved into such issues. What I remember from the code on small boilers if they run above a certain pressure 100 psig they are considered the same as the big boys and technically under all the same rules.

 

[Richard Hed]

I agree, but you have raised an interesting thought and that is how small a weld can be made and what would you use to keep the weld from blowing out on small materials. Time for a little research on micro welding. Using steel poses a corrosion issue that copper does not. However I have seen an industrial boiler made of stainless that was made for a brewery. And I have considered a boiler design made of steel for small hobby stuff but it would be difficult to make it look like the copper models you often see. And yes I think there is a provision in the code for certifying a pressure system with a hydraulic test. But its been awhile since I have delved into such issues. What I remember from the code on small boilers if they run above a certain pressure 100 psig they are considered the same as the big boys and technically under all the same rules.

It probably should be that way, as it is humongously dangerous and too many amateurs don't bother to pay attention to correct calculations and procedure. I thimpfks about air compressors, however, and it seems to me that the qualifications should not be all that different. Except for the heating and cooling stresses, that is.

I have an air compressor that goes up to 175psi, and really, it is far thinner material than a boiler. I realize there is good reason, if an air compressor happens to break, a large pressure of cool air blows out. but if a boiler breaks, it could be a general explosion (which might happen with a fire tube more easily than a water tube), or a stream of superheated water/steam that can kill or potentially give 3rd deg. burns. Still, the calculations cannot be all that much different. Somebody please tell me where I am wrong.

 

[Weldsol]

I agree, but you have raised an interesting thought and that is how small a weld can be made and what would you use to keep the weld from blowing out on small materials. Time for a little research on micro welding. Using steel poses a corrosion issue that copper does not. However I have seen an industrial boiler made of stainless that was made for a brewery. And I have considered a boiler design made of steel for small hobby stuff but it would be difficult to make it look like the copper models you often see. And yes I think there is a provision in the code for certifying a pressure system with a hydraulic test. But its been awhile since I have delved into such issues. What I remember from the code on small boilers if they run above a certain pressure 100 psig they are considered the same as the big boys and technically under all the same rules.

If you want to TIG weld thin section steel the biggest problem is any air gaps in the joint as the arc power (AMPS) needed to get full penetration on a closed butt weld would be too hot at an air gap and one edge will disappear
The same applies to fillet welds on tubes that go through the shell and if you have a thick to thin junction again if you get an air gap in the fit up you will lose the thin section.
When welding thick to thin then you need to offset the tungsten toward the thicker material and always add your filler wire on the same line so it floods across to the thinner material also you could use pulsed TIG if your machine has a pulse facility. this will control the heat input a lot easier (note only add filler wire on the peak current )
On steel if you try to TIG without filler wire you can get porosity due to lack of deoxidants in the weld pool you should be using a triple deoxidant TIG filler (Manganese / Silicon / Aluminium)
Paul

 

[Richard Hed]

If you want to TIG weld thin section steel the biggest problem is any air gaps in the joint as the arc power (AMPS) needed to get full penetration on a closed butt weld would be too hot at an air gap and one edge will disappear
The same applies to fillet welds on tubes that go through the shell and if you have a thick to thin junction again if you get an air gap in the fit up you will lose the thin section.
When welding thick to thin then you need to offset the tungsten toward the thicker material and always add your filler wire on the same line so it floods across to the thinner material also you could use pulsed TIG if your machine has a pulse facility. this will control the heat input a lot easier (note only add filler wire on the peak current )
On steel if you try to TIG without filler wire you can get porosity due to lack of deoxidants in the weld pool you should be using a triple deoxidant TIG filler (Manganese / Silicon / Aluminium)
Paul

I'll look for some of that 3X TIG filler.

 

[Richard Hed]

Ah, the deoxidant turns out to be standard issue.

 

[Steamchick]

Hi Richard, your questions are pulling good answers from the knowledgeable members. - Thanks Weldsol, HMEL, n all.
re: " Still, the calculations cannot be all that much different. " - You are correct. Hoop stress calculations etc. for pressure vessels are standard mathematics. But the Regulators - with their wisdom from Professional engineers in the appropriate trade, Insuranc e companies, lawyers, and other busy bodies - compile "appropriate" limits for stress appropriate to the industry and application.
1: They don't want to cripple industry, but
2: They DO want to keep us ALL safe. (- From injury, and possibly litigation?).
So they set limits appropriate to the agreed concensus of the experts, for the appropriate applications.
"Ours is not to reason why..."
So I follow "best practice" where I can, or at least ensure I achieve or exceed the requirements of the UK regs. (That's where the law applies to me).
I reckon the US regs: (ASME) - which would be used as the standard in a court of law the the ol' US of A - are probably as good as you get. - So many countries simply adopt those anyway (Even if they use their own letter-head!).
Is that of any use?
K2

 

[Weldsol]

Ah, the deoxidant turns out to be standard issue.

Yes all welding wires have some deoxidants
A15 spec is triple deox, but not the same as gas welding filler
MIG wire for mild steel is normally A18 and is double deox, (you were able to also get it in triple but not sure if that is still available now)
Also I would suggest you ask for a test cert when you purchase (will be at additional cost) as that would be required if you went for full boiler test
Paul

 

[sutty]

Camp stove forum? Can you send me a link?

classiccampstoves.com/search/29232362/?q=turm&t=post&o=relevance

 

[Richard Hed]

Hi Richard, your questions are pulling good answers from the knowledgeable members. - Thanks Weldsol, HMEL, n all.
re: " Still, the calculations cannot be all that much different. " - You are correct. Hoop stress calculations etc. for pressure vessels are standard mathematics. But the Regulators - with their wisdom from Professional engineers in the appropriate trade, Insuranc e companies, lawyers, and other busy bodies - compile "appropriate" limits for stress appropriate to the industry and application.
1: They don't want to cripple industry, but
2: They DO want to keep us ALL safe. (- From injury, and possibly litigation?).
So they set limits appropriate to the agreed concensus of the experts, for the appropriate applications.
"Ours is not to reason why..."
So I follow "best practice" where I can, or at least ensure I achieve or exceed the requirements of the UK regs. (That's where the law applies to me).
I reckon the US regs: (ASME) - which would be used as the standard in a court of law the the ol' US of A - are probably as good as you get. - So many countries simply adopt those anyway (Even if they use their own letter-head!).
Is that of any use?
K2

It's exactly what I would thimpfk. And I too don't want to hurt or kill anyone (except the international banksters) and am fully willing to follow regulations. What I DON't appreciate is all the over regulation on the inspec5tion stuff. It is well known that water tube applications are far less dangerous. It is my personal view that a good weld is a good weld and easily detected even tho' some may be superficial but look good. That's why individuals are tested to see if they know how to weld properly (and they also get the big $$ for their work). When it comes to commercial work, I suppose they are simply too big to ignore, even tho' most of those are far away from huge amounts of people it also matters if a plant goes down during winter or storms. For smaller builds, like a home build, I would thimpfk that testing the welder and pressure testing the build to 2-1/2 X NWP would be enough, and maybe a yearly test too.

BTW, I've been thimpfking, why could the insides of the pipes not be coated with some non-reactive metal like copper or chrome (or even gold, ha ha)?

 

[Richard Hed]

classiccampstoves.com/search/29232362/?q=turm&t=post&o=relevance

That certainly looks interesting. I will have a closer look after work. thanx

 

[Richard Hed]

Richard, HMEL knows more than I! - Thanks HMEL.
In the UK a steel welded boiler must be certified if over 3 bar-litres. (To the best of my knowledge). Material wall thicknesses must be a minimum of the metal thickness calculated for the strength of the boiler to resist the pressure, plus 3mm for the corrosion allowance. Welds must start and end on disposable tabs. Copper boilers use a factor of "zero" for the corrosion thickness. Model boilers in copper have traditionally had a factor of safety of 8 for the design stress versus UTS. I guess the same applies to welded steel boilers but need to check on that as I don't know.
I have employed Lloyds certified welders on contract jobs that required such and their welds looked "text-book perfect". Yes, paperwork is part of the job. Along with records of the approved component materials (controlled stock) and welding materials, current, gas, etc. ALL welds were visually inspected by the inspector.
K2

What exactly is your definition of a "disposable tab"?, por favor.

 

[Richard Hed]

Hi Richard, your questions are pulling good answers from the knowledgeable members. - Thanks Weldsol, HMEL, n all.
re: " Still, the calculations cannot be all that much different. " - You are correct. Hoop stress calculations etc. for pressure vessels are standard mathematics. But the Regulators - with their wisdom from Professional engineers in the appropriate trade, Insuranc e companies, lawyers, and other busy bodies - compile "appropriate" limits for stress appropriate to the industry and application.
1: They don't want to cripple industry, but
2: They DO want to keep us ALL safe. (- From injury, and possibly litigation?).
So they set limits appropriate to the agreed concensus of the experts, for the appropriate applications.
"Ours is not to reason why..."
So I follow "best practice" where I can, or at least ensure I achieve or exceed the requirements of the UK regs. (That's where the law applies to me).
I reckon the US regs: (ASME) - which would be used as the standard in a court of law the the ol' US of A - are probably as good as you get. - So many countries simply adopt those anyway (Even if they use their own letter-head!).
Is that of any use?
K2

One of the main probs is that different countries, even different manufacturors, will use different designations for the same product.

 

[Weldsol]

One of the main probs is that different countries, even different manufacturors, will use different designations for the same product.

All manufacturers of welding consumables etc, must supply to a specification this can be and is normally stated not to just one country so in the spec, it would conforms to B.S> xxxx AWS xxxx EN xxxx and so on
You cannot go on the manufacturers name of the consumable as these will be different in each case
Paul

 

[Weldsol]

It's exactly what I would thimpfk. And I too don't want to hurt or kill anyone (except the international banksters) and am fully willing to follow regulations. What I DON't appreciate is all the over regulation on the inspec5tion stuff. It is well known that water tube applications are far less dangerous. It is my personal view that a good weld is a good weld and easily detected even tho' some may be superficial but look good. That's why individuals are tested to see if they know how to weld properly (and they also get the big $$ for their work). When it comes to commercial work, I suppose they are simply too big to ignore, even tho' most of those are far away from huge amounts of people it also matters if a plant goes down during winter or storms. For smaller builds, like a home build, I would thimpfk that testing the welder and pressure testing the build to 2-1/2 X NWP would be enough, and maybe a yearly test too.

BTW, I've been thimpfking, why could the insides of the pipes not be coated with some non-reactive metal like copper or chrome (or even gold, ha ha)?

Re your idea of coating the insides of the pipes, sorry to be a killjoy but any coating would have to be after any welding is carried out as the welding would one burn of any coating and two the coating would more than likely decompose during the welding and give porosity and or cracking.
It would help to slow down the corrosion problem by using a water treatment as this does coat the inside of the surfaces, but don't over dose it as it would probably give rise to priming (I know I overdosed my Shay on its first steam up and got soaked )
paul

 

[abby]

Preferential weld decay ? back in the early 1970's I was lab technician /weld inspector for a British aero space company. When TIG welding stainless steel we had to use Niobium stabilised filler rods. Long term contact with certain liquids causes corrosion of the weld due to the loss of alloying elements hence the need for the stabilised rods.
I believe there is also an issue with TIG welded copper boilers and the facts should be checked before spending too much cash.
It might also be pointed out that the rules and regulations are for boilers used in a public area and larger than a specific size which may vary in different countries but in the UK I think it is 1 litre capacity but I am sure someone will confirm/deny this figure.
Dan.

 

[Richard Hed]

Re your idea of coating the insides of the pipes, sorry to be a killjoy but any coating would have to be after any welding is carried out as the welding would one burn of any coating and two the coating would more than likely decompose during the welding and give porosity and or cracking.
It would help to slow down the corrosion problem by using a water treatment as this does coat the inside of the surfaces, but don't over dose it as it would probably give rise to priming (I know I overdosed my Shay on its first steam up and got soaked )
paul

If one could clean the insides of the boiler some way to accept a coating, actually, the whole thing would be an ideal container to fill with a liquid for electrolosys. If you could do electrolosys, which metal would be best?

 

[Richard Hed]

Preferential weld decay ? back in the early 1970's I was lab technician /weld inspector for a British aero space company. When TIG welding stainless steel we had to use Niobium stabilised filler rods. Long term contact with certain liquids causes corrosion of the weld due to the loss of alloying elements hence the need for the stabilised rods.
I believe there is also an issue with TIG welded copper boilers and the facts should be checked before spending too much cash.
It might also be pointed out that the rules and regulations are for boilers used in a public area and larger than a specific size which may vary in different countries but in the UK I think it is 1 litre capacity but I am sure someone will confirm/deny this figure.
Dan.

I'm sure that 'certain' liquids would dissolve any metal. Where I live a few years back a few people were killed because stainless pipes had deteriorated and exploded. The local food factories had to evacuate. It was spewing a deadly poison into the air. The pipes had not been properly inspected. However, we are talking about, basically, pure water. Is pure water going to deteriorate welds quickly?

 

[Weldsol]

If one could clean the insides of the boiler some way to accept a coating, actually, the whole thing would be an ideal container to fill with a liquid for electrolosys. If you could do electrolosys, which metal would be best?

Personally I would go for the water treatment route as this coats all of the surfaces in contact with the water, a lot easier and cheaper, 99.9 % of people running a steel boiler uses water treatment ( as do all of the power stations )
Paul

 

[Weldsol]

I'm sure that 'certain' liquids would dissolve any metal. Where I live a few years back a few people were killed because stainless pipes had deteriorated and exploded. The local food factories had to evacuate. It was spewing a deadly poison into the air. The pipes had not been properly inspected. However, we are talking about, basically, pure water. Is pure water going to deteriorate welds quickly?

Depending on the stainless steel type you use it can be open to chloride attack at the water line .
it is possible to overcome this by using Duplex or even super Duplex grade of stainless.
In Libya when Gadaffi wanted to Irrigate the desert using sour well water they sank a pipe in mild steel down and it had rotted within 2months they then tried 316L stainless and that didn't last that much longer, we did a lot of work with a British company and ended up doing test pieces in super Duplex for them to do a hydraulic test and a G48 test, the pipe was 8" dia, with a wall of 5/16" the bolting flanges were 2" thick cast in super Duplex all TIG welded.
The best laugh was that when we had to talk to the engineering company about the project their design engineer had specified 316 stainless bolts and we all knew what had happened to the 316L pipe.
Paul

 

[Richard Hed]

Personally I would go for the water treatment route as this coats all of the surfaces in contact with the water, a lot easier and cheaper, 99.9 % of people running a steel boiler uses water treatment ( as do all of the power stations )
Paul

yes, for sure