[Farmwelding]

At school we have wall mounted regulators for oxy-propylene torch, is there any tips from going from acetylene to propylene. Cutting 1/4" steel in a 2" circle. Positions and settings? Also, I've had an overall problem with both cutting types with shooting the molten metal back into the line I've already cut and welding itself back together. I've tried different angles but no results. Thanks, Nick.

[Darrell F]

Do you mean oxy-propane? If so, propane requires more oxygen for the preheat flame and a little slower cutting speed. There are four things required for successful cutting: proper tip size (and clean), oxygen pressure, speed, and clean material. The results you describe could be from a combination of any or all of these things. For 1/4" material you should use about a "0" tip and 25-30 psi oxygen. Hope this helps.

[Farmwelding]

No I mean propylene.

[Poland308]

Keep your tip clean and watch your torch angle and travel speed. Having the right size of tip is important for a clean cut. What pressures are you running?

[cornmuse]

FYI: Propylene is Mapp gas. hotter than propane, I got a 2 (or so) gallon tank of it. I learned the hard way, dont use it on my bbq grill !!

-c-

[Boomer63]

For oxy/acetylene try your gas at 10 and oxy at 40. That should be plenty. When you are cutting holes in plate steel, start off center with a pilot hole. Angle your torch so that the slag doesn't go back into the tip or all over you. After you start you pilot hole, work towards the edge of the line you have drawn for you finished hole. Cut inside the line. Thinner metal, move faster. Angle your torch tip a bit, aiming towards the direction you are traveling. Thicker iron, keep your torch more vertical. Don't be afraid to push the lever all the way down! Sometimes beginners only push it half way down. I adjust my torch as much by sound as by sight. Most guys will tell you to turn on the gas until the black parachutes disappear, but I leave it to where they are still forming, just a bit. But that is just me!

Let us know how this is working out for you.

Gary

[Farmwelding]

I believe I was using 10 and 40 with the propylene.

[Boomer63]

I believe I was using 10 and 40 with the propylene.

It has been so long since I have used that gas mix that I don't remember HOW to use it! I think the last time I got on MAPP or anything other than acetylene was around 1990 or so. And, I have forgotten what it was like. This is what happens when you have a brain injury and get old.
Gary