I spent some time with a wire wheel underneath. I don't feel it's 10% as bad as the guy made it out to be. There was less than 10 punky spots that opened up, all in one general area. The biggest game to beat was the "patch" the shop started and quit on. I got my hands on a tig welder and welded it in on Saturday. Their filler had cracked right down the middle of the beads and had to be completely ground out. It's like they'd had the wrong shielding gas or something.
The bottom was a little stressed from sitting on the trailer bunks nearby, and would move like crazy as soon as the heat from the weld spread out. So it was weld an inch, move to the other side, weld another inch, let it cool for 5 min, and repeat.
Not my prettiest welds, but I'm confident in them. Welding on your back overhead with the wind blowing isn't ideal fine tig conditions either. I used 5356 filler. The bottom it 6061-t6 and I'd guess that's the same garden variety sheet they got for the patch. Thank god for new inverter tig welders. Being able to adjust the arc characteristics and having a nice cone arc off a pointed electrode made it easy to use just enough heat. I ended up at 160A on the meter, about 3/4 pedal used. 88% DC+ @ 110A and 165A DC-, 275 Hz, no pulse, 3/32 pink ring thoriated tungsten, #7 gas lens.
I have never been able to get that cobramatic to run very well and am having problems with plugged cooler lines, so I decided this scow was good enough justification to upgrade a little. Just happened to see this on CL Friday afternoon. New in the box for right at half of new price. I had to order a WC-24 so it can play with the XMT304 or Trailblazer. If the right deal on an Optima pulser comes by, I'd grab it to do pulse spray, which is the only way to fly running alum wire. I will upgrade it to the centerfire contact tip/diffuser/nozzle as soon as the tips that came with it get burned up.