Just did a quick Google. Seems like the 30 amp welders can weld down to 24 gauge. The sheet metal on these trucks is mostly 20 gauge IIRC. Should be alright with a 30 amp minimum. Here's a link to a Lincoln at Home Depot that would work also:
http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053