I should read the rest of the thread, but get a bottle of argon, blow out your liner with compressed air and give it a shot using what you have already. Don't forget to prep with a stainless steel wire brush and acetone. If your liner hasn't been used a lot for steel it might work. I am sure not an expert but I did build a motor driven yard kart for the grand kids using a Miller 172 MIG without a spool gun, just the welder. It was a learning experience on even new aluminum square tubing!
Originally Posted by peter94
In the mean time I took a class in TIG welding, purchased a Miller 180 SD to use at home and got decent welds on aluminum and stainless. But it took lots and lots of practice. When you get good enough with TIG welding aluminum, then I would consider your boat repair using that process.
Journeyman Refrigeration Pipefitter
Miller MaxStar150 TIG/Stick Inverter
Miller MM175 MIG
EMCO Maximat - Super 11 Lathe
Grizzly X3 Mill