what is best filler for oxy propane on various metals?

[BrokenBiker]

firstly, although I have welded and cut with oxy/acetylene,

I have yet to do anything with oxy/propane.

are there any metals you cant weld with oxy/prop?

also, which are the best rods for each metal?

 

[wyn]

I don't think you can weld much at all with propane.....i think it's all to do with the shape of the flame or something like that....there are a couple of posts around that explains it all.

 

[BrokenBiker]

I have seen people in work braze quite a lot with it, and im sure I have seen people welding mild steel sheet using strips of steel they have cut off as filler.

its not a problem as I only really want it for heating and cutting, just thought I would ask

 

[Wendelspanswick]

Oxy/Acetylene for welding, not heard of Oxy/Propane for welding.

 

[Lawnmowerboy]

You can't weld with oxy/prop as the propane lacks the shielding effect the acetylene has. Propane burns hotter than acetylene but not concentrated enough as well apparently.

 

[hotrodder]

Oxy propane provides more BTUs of heat but the max flame temp (while well above the melting point of steel) is ~350C lower than with O/A [/pedantic]
With acetylene the primary/inner flame gets it's O2 from the bottle and combustion in the secondary/outer flame uses O2 from the air resulting in a CO2 shielding effect. Compared to everything else O/A has the 'hotest' primary flame and the 'coolest' secondary flame
Propane gets all it's O2 from the cylinder (mixture ratios are very different!) so no shielding effect. It produces most of it's heat in the secondary flame, more than double that of O/A while the inner cone is getting on for half that of acetylene so even if 'burnt' welds weren't an issue (it isn't when flux used for brazing for example) focusing the heat to weld would be

 

[BrokenBiker]

cheers guys, will just stick to hot work and hardening and brazing then