Thread: Different gases for welding

Propane and butane are -ane hydrocarbons
Propane = C3H8
Butane = C4H10

Acetylene is ethyne (systematic name), ie C2H2. It's not stable unless in solution, so they dissolve it in acetone.

Generally you will find LPG, or "propane" is about 2/3 propane to 1/3 butane or less. Actual "butane" canisters are closer to pure butane though. I believe butane burns hotter than propane and is more expensive.

Edit: Out of all of these gases, oxy+acet is the only way you can weld steel. The others will do brazing or braze welding only.

Acetylene burns with reasonable heat, but is a carburising flame, so it's mixed with O2 to allow it to burn completely, which gives you a very hot, focused flame.

Thanks for the quick response Edd.

Would one gas be better than other or does it just depend on the application.

Rgds

Well it really depends. What do you want to do?

Butane is generally for small, focused flames, useful for pencil torches, soldering, jewellery and the like.

LPG is better for a bigger flame for heating, bending, maybe brazing silver soldering. And a 9kg gas bottle is pretty cheap to swap over compared to tiny butane cylinders.

Oxy LPG gives you more heat than LPG which means you can have a finer flame and comfortably braze weld and cut as well.

Oxy acetylene does everything that oxy LPG does, except it will weld as well.