# Soldering Brass.... questions.



## PapaPerk (Nov 7, 2009)

Hello,

I'm getting ready to repair a small brass steam engine I made when I was younger. It's made from brass tubing and was soldered using a big propane torch and electrical solder I believe (what ever I had laying around).

Anyway what does everyone use for soldering brass (type of solder). And also what are your recommendations on soldering device (torch, pen torch, etc). I know the live steamers do alot of solder and metal work... so that's why I'm asking here.

Thanks for the help guys!


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## Steve Stockham (Jan 2, 2008)

It sounds as if you are repairing the solder joints in the boiler? If so, this needs to be silver soldered with a good flux and then given a "pickle bath" afterwards. Also, the brass needs to be cleaned up before any of this can start. It's not terribly complicated but it is not as simple as soft soldering a joint! I would seriously recommend finding someone that has done this to mentor you through it the first couple of times! 

I just re-read your post and I'm assuming that this brass locomotive is electrical? If so, soft soldering will work fine and heating the brass with a small map gas torch should give you an even heating.


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## Semper Vaporo (Jan 2, 2008)

Silver soldering at this point will be useless... unless you remove ALL remnants of the "electrical solder". Otherwise the joints will be just as unsafe as they are now.

Yes, I know there are those that use plain Tin/Lead solder on boilers, and will claim there is no problem doing so. I suppose if they are using only the Esbit tablets or Sterno (jellied alcohol) for fuel it MIGHT be somewhat safe if NEVER run low on water.

BUT if you are using any other fuel (wicked alcohol, butane, etc.), then you risk destruction of the boiler if it is allowed to get low on water, with possible injury to anyone near the boiler due to rapid steam release from a melted solder joint.


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## Semper Vaporo (Jan 2, 2008)

Not only that, but "brass" is not a good material for boilers! Should be "copper"... and of something lots heavier than DWV pipe. Type "M" (the thinest of the common water pipes for sale at the big box stores, but in some states is not "legal" for pressure water pipes, even though sold for that purpose) is often used for the barrel, but too thin for end plates. Type "L" would be better, type "K" is best.


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## SteveC (Jan 2, 2008)

Posted By PapaPerk on 02 Mar 2010 09:13 AM 
Hello,

I'm getting ready to repair a small brass steam engine I made when I was younger. It's made from brass tubing and was soldered using a big propane torch and electrical solder I believe (what ever I had laying around).

Anyway what does everyone use for soldering brass (type of solder). And also what are your recommendations on soldering device (torch, pen torch, etc). I know the live steamers do alot of solder and metal work... so that's why I'm asking here.

Thanks for the help guys!
Well, to me the first thing that needs done, is you need to clarify just what it was that you built.
[*] A model locomotive built out of brass tubing and powered by an electric motor... or
[*] An actual Live-steam locomotive, where the boiler was built out of brass tubing and was expected to contain water, be heated by an external flame of some type, & be expected to operate under the pressure of the steam generated.
[/list] The reason for the needed clarification is the techniques, tools, type of solder to be used, and advise given will depend on your answer.


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## xo18thfa (Jan 2, 2008)

If you are talking about repairing a live steam boiler that was originally made from brass and soft solder, you can certainly repair it, but don't run it under steam. It is better to retire it.

To answer the question, however, I use 50/50 solid wire solder. That is 50% lead and 50% lead. You can also use 60/40, 60% lead 40% tin. There is even 70/30. The difference is the melting temp. The more lead, the higher the melting temp. I use 50/50 because it's a good general purpose solder and I have a ton of it. Flux is critical, even in soldering brass. Now-a-days there are a lot of water based fluxes. I have never had luck with them. The old fashioned brown petroleum based paste flux is better. For heat, a regular bernz-o-matic torch is all you need. 50/50 melts and flows at 413 degrees F, which is literally a candle's worth of heat. If it's been a while since you soldered, get out some scrap pieces of brass and practice. 


Once again, don't use soft solder and brass for live steam boilers. Practice has changed a lot over the years and that is now quite forbidden.


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## PapaPerk (Nov 7, 2009)

Hello everyone. Thank you for the quick replies! 

I suppose I need to clarify what I'm soldering. My question was general. What solder and torch do you use to solder brass? One thing I will be soldering is a small oscillating cylinder brass engine I made when in highschool. It's a stationary engine.... not a locomotive. And is generally run off of air. Not steam. However I do have an "oil can boiler" that can power it. The oil can boiler uses a cork for a safety valve. Primitive stuff. ) 

So sounds like 50/50 is the way to go on the solder.


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## Havoc (Jan 2, 2008)

You could also use some Pb93SnAg1.5 solder. This is a "high" temperature (296°C) soft solder that has a high creep resistance. You can often find it in small rolls at the diy shop. Use the same flux as the other solders. It is also used to solder electromotor commutators, another place where you could find a bit of it. Depending on how large that engine is a large electric soldering iron might be enough or a small gas powered one with a flame (like the ones used in the kitchen for crème brulé).


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## seadawg (Jan 2, 2008)

I like crème brulé!


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