Need help tigging stainless!!!
I need some help from those of you who have welded stainless. What if any changes do you make when going from mild steel to welding stainless. A buddy of mine has an Invertec (DC only) with a high frequency starter and remote setup on it. After about an hour or two of practice, adjusting amperage and general experimentation with the various ***** and switches, our practice welds with plate steel look awesome. We are really pleased with how it's turning out. We now want to tackle stainless steel. We had some polished stainless tubing from an aftermarket exhaust system lying around. So we cut a piece of the pipe and attempted to weld it. Somehow the Tig torch starts acting like a plasma cutter. I am barely on the pedal for a second and I have already torched a dime sized hole in the material. We have the amps turned down to 1.5 on a 1-10 scale. We have tried reversing the polarity which destroys the tungsten AND the material as opposed to just the material. There are two more rotating ***** and a switch for 2-step and 4 step on the remote box (that handles the hi-freq start). One of the rotating ***** sets the gas flow period after you let off the pedal. The other looks to be for adjusting the rate at which the amperage tapers off when you let off the pedal. What does 2 step or 4 step do? Any recommendations would be appreciated. I really don't want to have to mig weld my stainless headers together.
4 step is good if you need to scratch start or aren't adjusting the amps remotely.....then you can use the slope up and slope down features.........do a nice slope up and that may help your problem....
i'm guessing you aren't adjusting the amps remotely?? then you pry want to try the 4 step and mess with sloping the current......keep the gas pressure so that you can barely feel it at about 4 inches from your face(pry 15-20) and make sure the gas is coming on before the arc strikes.....remember if you get into any serious stainless welding that butt welds and the like should be back purged with argon....if not the back of the weld will sugar from the chromium burning out and it will be contaminated and rust
i've only used a 4 step machine a few times at our tech center, so maybe someone else has a better idea of exactly how to set you up......
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this may sound like a dumb question, but is the machine set to remote control? there is probably a **** for panel control or remote control, if it is already set to remote then maybe the switch is broken?
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this may sound like a dumb question, but is the machine set to remote control? there is probably a **** for panel control or remote control, if it is already set to remote then maybe the switch is broken?
) no matter where the dial is set. So some of the students that I teach aren't aware that you need a light foot on that machine and they end up burning up cup's, tungstens, and their stainless pieces.
We've had a Miller rep come out and knew exactly what the problem was. I think he said the master output switch was bad. Aparently it was a warrenty issue. Their new machines have the problem resolved. To fix it was going to cost $600 for the part + one hour of labor.
Burning stuff up would tell me no gas or amperage to high.
Also when welding stainless you want to use just enough heat to get a molten puddle. Any more heat will result in contamination and suck back.
FWIW: The tungsten should be the same diameter as the metal you are welding. The tungsten stick out should be no greater than the cup diameter. The cup diameter should be 4 times the diameter of the tungsten (1/16" tung = 4/16 or 1/4" or #4 cup) Post flow should be 1 sec for every 10 amps.
These are general recommendations.


