I have never posted to any forum, but need to give it a try. I’ve been welding for about ten years. The company I work for only does wire feed, on any thickness and type of material. we built a part that we build several of them, but needed 60 welds plus a very long seal weld. we did everything we could do to minimize warping. (it’s 16ga with some 12ga). I haven’t tig welded in 8 years, but we’re gonna build one doing it that way and see if it turns out better. if not, then the salesmen can deal with it, he sold something he shouldn’t have. So 12ga to 16 ga lap and fillet. 12ga formed channel welding both sides. the seal weld is 16ga to 16ga butt with and 11ga tube behind it. the gap for the seal weld is about 1/8″ and can’t be changed much. I’m curious about tungsten electrode size and type, also filler metal size and type, and any other tips may help. thanks!