I haven't been tigging long, but this summer I have run through a couple of big tanks of argon. I get the black when i touch the tungsten to the work piece. For a beginner it is near unavoidable. You must use a grinder wheel dedicated to only grinding tungsten. if you intend to weld aluminum, you need a second grinder wheel for only aluminum tungstens. Once contaminated, you have no choice but grind the electrode. Some experts say grind back past the contamination, others say break it off, then re sharpen.Stick out about the diameter of your tungsten. Arc length about the diameter of your tungsten. This won't be easy, do the best you can. Pre flow is important. Post flow is also necessary. Check the manual it is often adjustable. Don't move the torch away for a few seconds after extinguishing the arc. Flow rate is important, too much will cause turbulence'and bring air into the mix. Too little, you won't get coverage.Failure to grind paint, grease, or rust far enough away can cause blackening.
Today I welded outdoors, almost no wind, but still a problem with gas coverage.
Stay with it, it will get better.
