Oxy / propane bronze welding

[outofthefire]

I have had a few requests for work from the states that will need me to heat up steel quicker than my compressed air/propane burner can handle and I can't use my coke forge because of the neighbours. So it looks like it might be time to invest in some gas welding gear, Oxy/propane would be fine for heating but thinking about the future could I bronze weld with it or would I need acetylene for that?

 

[Lawnmowerboy]

You can braze bronze with the right filler and flux with oxy prop.

 

[outofthefire]

You can braze bronze with the right filler and flux with oxy prop.

Bronze welding and brazing are different things bud.

 

[gordon stephenson]

Don't sculptors repair flaws in bronze castings using tig.

 

[outofthefire]

Don't sculptors repair flaws in bronze castings using tig.

I dont want to weld anything made from bronze.

I want know if I can bronze weld with oxy propane

 

[brightspark]

I dont want to weld anything made from bronze.

I want know if I can bronze weld with oxy propane

as in join 2 pieces of steel together using oxy propane ???{braze together } using bronze rods ??

 

[Paul.]

The problem you will have with oxy propane is not being able to concentrate the heat in the weld pool, oxy acetylene being a concentrated flame allows you to produce the welded joint with minimal heat input, so for a proper bronze or brazed weld I would say its not suitable, although I've never actually needed to try it as always had O/A available.
As you rightly say brazing and bronze / braze welding are two different things, brazing generally refers to a capillery process and relies on surface area to provide strength, as opposed to bronze and braze welding in which the joints are prepared much as they would be with full fusion welding using vee prep., j prep etc on plate and sheet, and the use of bell joints for pipework,
As you will know there are a wide range of fillers available, with the term "bronze welding" referring to the use of copper rich alloys.

 

[outofthefire]

Yes, I thought bronze welding was a more familiar process than it appears. There is more info here http://www.weldcare.co.uk/app21.htm

Oxy propane should easily be hot enough I just don't know if the flame will be too dirty and leave impurities in the weld and wether I can use a normal oxy/acetylene torch with oxy/propane, I know you use a different nozzle when cutting with oxy/propane

 

[Paul.]

Its not just about flame temperature, the chemistry is different, an O/A flame draws some of the oxygen required from the atmosphere, around 1.5 times the amount fed from the cylinder, this secondary burn is what make the outer cone of O/A flame de-oxidising or reducing, for braze welding, nozzle sizes are typically smaller than you might use for fusion welding to keep the heat input low and concentrated.

 

[outofthefire]

Cheers Paul thats what I wanted to know.

 

[Fazerruss]

sorry to hijack the thread outofthefire but I noticed you mentioned using a compressed air/propane torch. How hot can it warm up steel? Do you have a picture of the torch or can tell me more about it. Reason I ask is Id like a substitue for my oxy propane set up. I already have a tig and a plasma but would like a torch that will get as hot or close to oxy propane but without the need for a oxy cylinder. I could then get rid of the propane, oxy acet equipment but still have some serious heat on tap.

Thanks
Russ

 

[brightspark]

sorry to hijack the thread outofthefire but I noticed you mentioned using a compressed air/propane torch. How hot can it warm up steel? Do you have a picture of the torch or can tell me more about it. Reason I ask is Id like a substitue for my oxy propane set up. I already have a tig and a plasma but would like a torch that will get as hot or close to oxy propane but without the need for a oxy cylinder. I could then get rid of the propane, oxy acet equipment but still have some serious heat on tap.

Thanks
Russ

heres a flamefast gas and compressed air gun give u some idea. u cant realy localise the heat the same as oxy acet or oxy propane

http://www.youtube.com/watch?v=zuvzxxwBzow

 

[hotrodder]

Yes, I thought bronze welding was a more familiar process than it appears. There is more info here http://www.weldcare.co.uk/app21.htm

Oxy propane should easily be hot enough I just don't know if the flame will be too dirty and leave impurities in the weld and wether I can use a normal oxy/acetylene torch with oxy/propane, I know you use a different nozzle when cutting with oxy/propane

The flux takes care of impurities when brazing and bronze welding/fillet brazing*
As Paul said oxy propane isn't quite as nice to use for this sort of thing... it produces most of it's heat (BTU's not temp) in the outer flame i.e. the heat isn't as focused. It's oxidising properties aren't a big deal with brazing as besides the flux a slightly oxidising flame helps prevent zinc volatilisation, especially with traditional flavours of brazing wire as they don't have much silicon in 'em. While propane is cheaper than acetylene you'll get through oxygen faster

You can use a regular O/A welding torch with propane although there are different mixers and tips/nozzles available some flavours of torch. Propane fuel hose is different to acetylene

You can also braze with TIG, the wire is different (no zinc) and it doesn't wet out as well



*personally i prefer the term 'fillet brazing' as it tends to avoid confusion imo

 

[outofthefire]

sorry to hijack the thread outofthefire but I noticed you mentioned using a compressed air/propane torch. How hot can it warm up steel? Do you have a picture of the torch or can tell me more about it. Reason I ask is Id like a substitue for my oxy propane set up. I already have a tig and a plasma but would like a torch that will get as hot or close to oxy propane but without the need for a oxy cylinder. I could then get rid of the propane, oxy acet equipment but still have some serious heat on tap.

Thanks
Russ

I have a flamefast torch and another that is smaller and has a more focused flame but neither gets as hot as oxy propane. I can braze and silver solder no problem but you have to heat a large area. I also use firebricks to reflect the heat back into the metal.

I use the flamefast torch in a little one brick forge and that will get the 6mm round bar up to welding temperatures.