Welding w/Propylene

[Circuit Rider]

Haven't used a gas welder in 25 years. Wanting to buy one and read that Acetylene was in short supply. From what I can find to read there's both pro and con in using Propylene for cutting and welding. Any one that has experience with this gas I would appreciate your input. Thanks, CR

[DougGuy]

The primary flame cone of propene is only slightly less temperature than acetylene, but the secondary heat is said to be greater than that of acetylene. Acetylene flame with oxygen is 6300F so it would have a lot to it's credit if it can outdo that.

There is much greater flexibility in torch tips with acetylene than any other fuel gas, and the same torch head/mixer body might not work as good with propene.

One good thing about it, it can be used at full tank pressure where acetylene over 15psi is dangerous and over 20psi can become explosive and doesn't need an oxidizer or an ignition source other than the pressure itself.

And then there is this:

Propylene vs Acetylene
advantages

* more stable and safer than acetylene and no 15 psi limit on working pressures

* no soot

* more btu's of heat for heating large parts and thick metal

* cuts metal quickly and with a very long tip to work distance

* acetylene prices are rising much faster than propylene
* better heat transer properties than acetylene
* no withdrawal rate limitations

disadvantages

* cant gas weld with it...too much pressure and too much flow rate to weld metal with any quality

* requires different tips and T grade hose

* slight learning curve on lighting and setting the torch

[rockrat]

Little brother used propane for his cutting torch only. Worked very well

[MT Gianni]

Gas welding is fast becoming a lost art. It is too easy to over heat metal and stress things. Todays' mig, tig and wire feeds handle thin stock easily.
Acetelyne has a fuel air ratio burn rate of 1.5% to 98.5% gas to air. Propane 2.5% to 12.5%. It is a much narrower range of burn but if you can make it work it is cheaper. Acetelyne is much easier to keep in the proper burn ratio for newcomers.

[Circuit Rider]

Sorry, I didn't make myself clear. Don't want to use propane, just propylene. My main use is for cutting and will weld with my MIG. Looks like a propylene unit would do fine. CR

[DougGuy]

You should be fine cutting with it. I have been a burner by trade since 1970 in a bunch of shipyards and other heavy steel fabrication places building oil rigs, pressure vessels, etc. I used acetylene for 95% of those jobs. Cutting and beveling steel 2" and 3" in thickness was just another day at the office to me. I had good nerves then too and was a lot smoother with a hand torch than I am now.

I used propane for cutting and it was barely passable in this capacity. I used MAPP gas for cutting, beveling and washing welds, it did good enough but needed special tips and was slow in coming up to heat.

Propene (propylene) by the description sounds a LOT closer to acetylene for cutting than any of the substitutes, and better than acetylene for preheating.

Nowadays I use a lot of .045" cutting wheels on a 4'" grinder when and where I can as they are cheaper than any of the fuel gases and oxygen.

[M-Tecs]

http://www.weldingtipsandtricks.com/oxy-fuel-cutting.html

[Circuit Rider]

Gentlemen, Thanks for your help, It's greatly appreciated. CR

[frankenfab]

I had heard the same thing about the shortage, but I was still able to get my bottle filled at Welsco. I don't remember how much it was, but it didn't seem like they were gouging me.

This was 6 months ago. Something about acetylene manufacturer having a big catastrophe?