spider, you're making good use of your time over in the oil patch!
Avatard, SS doesn't warp with heat (fire pan) as badly as mild steel or aluminum. SS does warp a bit when welding.
Molten steel/slag generally doesn't stick to copper, so it's common to back thinner welds with scrap copper or a copper bar. That piece of copper can also be used to exclude atmospheric oxygen. Small, quick, low-heat welds, not too much porousity.
Spider, thanks again for the advice. I did turn up my wire speed and it helped a lot. My SS welds last night went a lot better. I suspect part of my problem is that my liner is a bit large for the small 0.023 wire I'm using. It made the wire slightly "surge-y". Faster wire speed tended to even out the wire feed rate. It helped to keep my torch feed in a big sweeping curve out from the welder and to my gun and made sure I had no sharp bends--good advice anyway--but more critical here.
This is the camp water kettle I've been building. It started out as a 1.5gal SS water softener tank from a coffee shop. I was having burn-through problems when I was welding the spout to the body (~20ga). Last night, I was mostly welding thicker (~14ga) material for the handle. Slightly thicker was a lot more forgiving. I really kept the puddle moving when I was welding the handle and tabs to the body.
Looking at your welds, I still have a long way to go, but I also know this weld is good enough that I'm not going to lose a handle while this 1.5gal kettle is serving camp hot water duty!! I've got about $2 in the tank and $0.50 in the lid from Salvation Army. I already had the scrap from which I made the handles and spout. Beats the heck out of paying $90 for a Partner kettle.
....and $22 in the 2lb spool of SS wire and $1,000 in my MM210!