# Propane burner for brass soldering ???



## ksor (Aug 19, 2013)

I seldon do this type of soldering so I'll not go into ecethylen/Oxygen but use propane !

And I CAN for very small items - but a little bigger items (6mm bolts) can't do it !

Can I find some burners for propane and compressed air ?

OR

Should I accept some "silver/brass/bronze" _BEEP_ ?  (I'm afraid of the strength or it's too soft !)

Any comments ?


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## jgedde (Aug 19, 2013)

What kind of solder?  Soft solder?  Silver solder?

John


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## ksor (Aug 19, 2013)

jgedde said:


> What kind of solder?  Soft solder?  Silver solder?
> 
> John



I beleave SOME if it CAN be used with pure propane and normal air - right ?

But I would like to use BRASS IF it can be doen with propane (combined with some compressed air) burner.


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## Codered741 (Aug 19, 2013)

The problem that you will run into is the BTU output from the propane torch.  Unless you use an Oxy/Propane rig, which is really more suited to cutting, you will be hard pressed to put enough heat into a substantial part.  

I will occasionally use a MAPP torch to braze and solder small parts in my shop.  But now that I have an Oxy/Acetlylene rig, The MAPP torch is relegated to heating parts for breaking them loose, or shrink fits.  

-Cody


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## DMS (Aug 19, 2013)

For larger parts, invest in some fire bricks. They really help  if you build a small barricade around the part to help heat loss.

I have done a fair amount of soldering with a simple propane torch. For larger things I use a welder (I have a small wire welder, much faster and stronger for steel).

Are you talking about joining two brass parts together, or joining two steel parts with bronze brazing rod? If you are talking about brass parts, I would stick with silver brazing, and a small propane torch should be enough unless the part is really large. Strength in brazed joints is mostly about joint type. For example, butt joints are very week, but lap joints are very strong. It's all about how much surface area the joint covers. Silver brazing can be very very strong if the joint is designed properly.

You may take a look at a jewelry supply house. Jewelers tend to use small torches for soldering and melting metals for casting. There are a large variety. I don't know about local availability for you, but where I am, small O2 tanks are available from most hardware stores.


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## ksor (Aug 20, 2013)

>> DMS

Yes, I was "joining two steel parts with bronze brazing rod" but didn't succeed - I'm sure not enough heat.


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## DMS (Aug 20, 2013)

ksor said:


> >> DMS
> 
> Yes, I was "joining two steel parts with bronze brazing rod" but didn't succeed - I'm sure not enough heat.



Are the parts clean of scale? Also, what type of flux are you using (pre-fluxed rods, or powdered flux?)? You will want to get the base metal to at least a cherry red. I have a feeling you are not getting enough heat. When I did this, it was with an Oxy/Acetylene setup. I tried using nickel-silver rod (which has a slightly lower melting point), with a propane/air torch, but could not get things hot enough.


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## ksor (Aug 20, 2013)

DMS said:


> Are the parts clean of scale? Also, what type of flux are you using (pre-fluxed rods, or powdered flux?)? You will want to get the base metal to at least a cherry red. I have a feeling you are not getting enough heat. When I did this, it was with an Oxy/Acetylene setup. I tried using nickel-silver rod (which has a slightly lower melting point), with a propane/air torch, but could not get things hot enough.



Yeah, I was using a propane/air torch and COULD heat p the "small" part to solder temperature but a "bigger" 6mm bolt I COULDN'T - all CLEAN material, flux BORAX and brass rods.

I DON'T wanna go into Oxy/Acetylene.

One other member said something about getting some stone to make a small Owen ... maybe.


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## DMS (Aug 20, 2013)

You shouldn't need oxy/acetylene for this, but you may need more than propane air. If you have a source for compressed oxygen, or can invest in an oxygen generator, I think that will work. The temperature of an oxy/propane torch is not much less than an oxy/acetylene torch.

http://chemistry.about.com/od/firecombustionchemistry/a/Flame-Temperatures.htm


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## Hawkeye (Aug 20, 2013)

I have done a lot of silver soldering of steel and brass parts. For something like your 6mm bolts, I would think it strong enough. I've generally used a normal propane torch. For parts a bit bigger, two torches will bring the temperature up to the working point, then set one aside and use one torch to control the heat to flow the solder around the joint. Silver solder, like soft solder, follows the heat.

For health reasons, choose a cadmium-free silver solder and use a good quality flux made for the purpose.

For parts requiring more strength than silver solder can provide, I use a MIG welder.


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## Smudgemo (Aug 31, 2013)

I agree with DMS- LP/Oxy is plenty.  In fact, you can simply steal the LP tank from your bbq grill and using bottled oxygen or a medical oxygen concentrator, you'll have plenty of heat to braze with bronze.  There is a long thread here with a bunch of good info on the subject.  Granted it's regarding the manufacture of bicycle frames/forks, but it should be relative.  Since LP is so much less expensive than acetylene, I bought a few torch tips to give it a try.  O/A is easier to control (for me), but LP works fine.  Can't gas weld with LP, but I'm planning to buy a cutting head for my torch since that works.

Brake post mounting is a common use for bronze in bike building, as is attaching pretty much everything else.




Plenty strong, and completely withing the capability of an aircraft torch and LP/O2.  I can't personally speak to the oxygen concentrator part, but I'm thinking I'll give it a look one day.  I like the idea of not relying on Airgas when any 24/7 gas station has LP tanks and you make Oxy in your garage.  High quality bronze, silver and the associated fluxes can be purchased from Cycle Design Group or Henry James (Harris & Gasflux stuff.)  The bronze flows really well, and the flux washes off in hot water.  Much better than the flux-coated rods in the bargain bin at the local weld shop where you have to chip off the flux.  

-Ryan


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