Gas Welding

[labmaster02]

I have a MM211 and love mig welding, but I'd like to get better with the oxy-acetylene. I hope some people here have some experience with the gas. I'm have a problem with flashbacks when the torch pops and squeals. This is the result of the flame backing up in the handle. It happens just about every time the puddle starts to form and I start adding filler. I'm welding 1/8 steel with a #2 tip, neutral flame, 4psi acetylene and 5 psi oxygen. Everything seems right this doesn't make sense. I don't know if there's something wrong with the handle. I don't have any problem while cutting. Has anybody seen this or have any suggestions? Thanks

[caddidaddy55]

You didn't mention your torch type so I can't give you a tip #, but you should use a tip with a #57 drill size opening (.043") both gasses at 10 PSI for 1/8" material.

[labmaster02]

The torch is Proweld, it's compatible to Victor. The tip is about .046, but it doesn't really matter which tip I use it does the same thing. 10 psi seems like a lot for acetylene for welding. Everything I read seems to stay below 5. I've tried more pressure, but not up to 10. I can try it and see.

[stronics]

Your about right at the 4 & 5 lbs setting. Turn the acet at the torch till you get a full feather flame, or slightly less, then adjust the oxy to a neutral flame. If too much heat go to the next size smaller tip.
David

[labmaster02]

I open the acetylene until the soot stops then adjust the oxygen until I have the small blue tip. It's kind of loud but supposedly correct. Then I start heating the metal and after the puddle forms and the small sparks start I add the filler and it pops then starts squealing. I have to shut it all down. I tried different tips and the same thing. I tried less acetylene and then it won't melt the steel. I'm not touching the metal or the filler rod with the torch. It's really aggravating and dangerous. I have check valves but just ordered flash back arresters just to safe. I'll try a smaller tip and a little more distance this weekend and see if it helps.

[Meltedmetal]

Have you checked the o-rings on your tips?

[Gobysky]

My experience with this kind of welding dates back over 40 years ago. Brings back a lot of memories. I used to weld on aircraft tubing. Haven't done much of that kind of welding since then.

But one thing comes to mind. Whenever I held the torch too close to the molten metal, the tip would overheat and backfire. I hated it. Sparks and molten steel would fly everywhere.

If I remember right, it was not good to bury that inner blue flame in the metal. How close have you been holding it?

Also, keeping that tip clean was equally important.

[Helios]

I'm no expert but it seems like sometimes you can get the flame too oxygen-rich and that will cause oxidation of the steel/popping. Try setting your flame to neutral, then back off on your oxygen just a hair so that you just begin to barely see the edge of the feather of a reducing flame.

[labmaster02]

Thanks for all the the advice. I opened up the handle and found lots of soot. Then I checked the o rings in the mixer and the were dry rotted. I cleaned the soot out, but now have to find new o rings. I'm hoping this is the problem. As far as getting too close to the molten puddle, I tried staying further away but then had trouble keeping the puddle and it would still flashback.

[Gasrat]

I run both oxy/acet between 5 & 7 psig and you definitely want to have a neutral flame. The tip of your inner blue cone should be just above your metal. Close to, but not touching the metal while welding. Most common causes of popping are dirty tip, getting too close to your puddle with the flame, or starving the tip for fuel (having the torch turned down too low for the size tip your using). A #2 tip would be the size tip I would recommend for 1/8" plate. Have you checked your pressure at the gauge under flow? With the pressure set that low, some regs will drop considerably under flow as apposed to lock up pressure which would have you starving for fuel also. They're just a few suggestions, but I hope they help.