What's the odor you smell when you tig. I'm particularly thinking of tigging aluminum because that's where I notice it the most. It almost smells like chlorine, but not quite. Is that ozone? I don't tig often enought to remember whether it's there when welding stainless, but I was reminded of the odor when I tigged some aluminum yesterday. I first noticed it when I took a welding class earlier in the fall and was working on aluminum.