Paul,
We do alot of tig spot welding in our shop for the rail industry. The material we use it on is light gauge S.S.. You would not believe the job this process does. It makes a beautyful looking weld, and requires no filler material. you will need a power source with a timer. We use a Miller Syncrowave 250 DX, with the Tec Tig Spot gun. The gun is made by a company called TEC TORCH CO. San Marcos CA. I don't know if they have a web site, but I'm sure your welding supply house could give you more info. talk to them about your requirements, they will be glad to help.