I get asked “Can I weld with a Propane Torch”, a lot.
Sadly, the simple answer is NO, you need Oxygen and Acetylene to Fusion Weld.
Its not about heat because you can melt steel with Oxy/Propane
A lot of companies are now offering Propylene as an alternative to Acetylene. Oxy/Propylene is a lot hotter than Oxy/Propane but you still can’t successfully weld with it.
Oxygen + Acetylene produces a strong, malleable weld. Oxygen and Propane or Propylene will produce a hard brittle weld.
I confess I don’t fully understand the Chemistry that goes on (Chemistry was never my thing), but it involves “Redox Reaction”.
The simple way it was explained to me, by someone who does know about it, is that there is transfer of Electrons between an Oxygen+Acetylene Flame and Hydrogen atoms that are present in an Oxygen+Acetylene Flame. This is a Redox Reaction.
As there are no, or a lot less, Hydrogen Atoms in an Oxygen+Propane or Polypropylene flame, Redox Reaction takes place with the metal in the molten weld pool, Oxidising the molten metal.
The resulting weld is brittle, weak and cracks or breaks easily.
You can read more about the Redox Reaction via these websites:
I’ve read on some websites and forums that the Carbon atoms that part make up Acetylene (Acetylene is 2 atoms of Carbon + 2 atoms of Hydrogen, C2H2) combines with the Oxygen to form Co2 and that this acts as a shielding gas (a bit like Mig).
I find this implausible as Propane has 3 atoms of carbon, so why wouldn’t the same thing happen?
Anyway, I’m not overly bothered about the science because if it were possible to overcome the fact that you can’t produce acceptably strong welds with Oxygen + Propane/Propylene, someone would have done it and taken on the VAST Global Acetylene market.
The good news is that you can do pretty much everything else with Oxygen + Propane or Propylene. Assuming you have the right Torch or Kit.
Heating, Cutting, Brazing and Silver Soldering are all easy to carry out with Oxy/Propane.
You MUST NOT use an Acetylene Regulator, Acetylene Flash Arrestor or Acetylene Hose with Propane or Propylene. Propane and Propylene will corrode internal parts of Acetylene equipment, making it dangerous!!!!
I personally would not use Propane or Propylene with a Gas and Air Torch, except for soft soldering.
Gas/Air torches produce a reasonable amount of heat, but it is not very concentrated or focused and the significantly lower flame temperature means it can take too long to get the job to Brazing or Silver Solder temperature, thus allowing oxides to form.
“Can I weld with a Propane Torch”, NO! Harsh, but true 😀 However, with the correct equipment, you can do pretty much everything else.
Visit our Propane Torch page.
I hope this blog article useful, even if it din’t give you the answer you were hoping for.
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