I'm replacing the rear window to trunk panel on a 70, after removing the panel, found surface rust everywhere. It seems the most popular & trusted method of rust prevention in this area would be por 15. Has anyone tried to weld through this stuff using a resistance spot welder (i think thats the proper name) or will I have to grind it off in the area's to be welded? Thanks,
Terry

Weld it in first, apply Por last. I don't think I'd coat the surfaces with Por and then try to weld through it because the fumes are very toxic. Use 3M's weld-thru corrosion inhibitor on the mating surfaces, and Por 15 on the rest on the bottom side only.

[This message has been edited by Randy Mosier (edited 11-24-2002).]

With Randy on this. I highly doubt you could get electricial contact through the por. Grind down the entire area that will be welded on both mating surfaces. Dont grind just little areas for the weld grind the WHOLE seem. POR is very harmful to breathe and I bet the fumes from it burning would be deadly. Plus if the por would get into the weld pool it could ruin the weld.

Grind both edges then apply that 3M weld thru primer. It is full of zinc and will protect against rust. The good thing about it is it wont burn away like other paints would, it stays right there and seals up the weld...Eric

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1970 chevelle
1970 chevelle SS455 not a typo its a BUICK BABY
1949 and 1972 chevy trucks
http://briefcase.yahoo.com/bc/sevt_chevelles

Thanks guys, I wasn't aware that 3M made this product, and as I'm sure you both know, access is restricted in this area, once the panel is welded in place. You've been a great help,
Terry