The Stovebolt Site Forums The Shop Area Paint and Body Shop weld thru primer

I'm rebuilding a utility trailer and have it out for sandblasting. I'd like to prime it before I put the deck on and realize I will need to touch up after welding but I would like to prime it before I do any welding. Any suggestions? Rustoleum work?

Rustoleum will allow moisture to get to the metal.

If you are going to be a while before you finish paint, use an epoxy primer.

They sell weld-thru primers at welding supply shops, about $10-12 for a spray can here.

However...

You still need to weld on CLEAN metal; grind/disc/wipe all paint/primer off prior to welding. I know Don knows all this. I'm very new to welding auto-body ('pretty' stuff), but I used the weld-thrus for a long time & yes, you can weld through it...Depending on the gauge of the trailer steel, you will also need to crank the welder up with these primers...

The epoxy primer Tim suggests is the best primer I have used. It is also the hardest thing to get off when cleaning, prior to welding. That is a good thing.

I can't defend all this with 'I have xx years of experience', and an untold amount of variables are out there, but you need to do any & all metal welding on the absolute cleanest metal possible. Why not have the best primer coating possible? (if you do have to clean something off)

Brad

MIG and TIG welding works best on clean metal. Stick welding and Acetyline burns the paint away ahead of the weld, so it's not quite as critical to get picky about cleaning. It sort of depends on how smooth you want the finished product to be, and/or how much time you're willing to spend grinding and polishing the bead after the weld is done.
Jerry