Fixing a paint problem

[Bob_Koch]

Had a chance to visit Mark and Sean of Basix Hot Rods here in Santa Rosa. Got one technique that I'll be using on my truck and wanted to share it. My roof seam is full of rust and I wondered how I would get it cleaned out and keep corrosion from coming back. Welding the seam seems to solve the problem. They were working on a Ford cab at the time so here's pics from that.

[MBF]

Bob-if you can get it clean it can also be leaded (less heat). Are you trying to fill it in or just fill in the pockmarks? Mike

[Bob_Koch]

You're right - soldering would be a great way to go for those of us that have lead soldering materials to work with (which I do) and have the ability to lead ( which I barely do).

Mainly the idea is to rid the seam of rust forever. It's difficult to clean out and once rusted seems to become a reoccuring paint problem area.

[grey beard]

Had the same problems with my cab seams. It seems like a weak area for attracting moisture. I ground mine out with a 4-inch grinder, then used NAPA Rust Tretment, a white, milky liquid that works very well for me. I then sanded and primed in the usual fashion, and am very pleased with the results.

I have used this stuff in the past with good success. It will work in places where you can't get in to clean like you may wish to do, like door jambs and close cowl areas where body seam ends attract rust. If you use this stuff, get a small container and a stiff brush, and of course, never return any back to the can.

Works for me. I use it on both sides of a seam when they're accessable.

[moparvern]

First off let me thank you BOB for stopping by.

Second let me talk about seams. Typically if you weld slow there will be zero warpage as it is a 90 degree flange so it takes alot more heat to warp.

Lead or plastic filler is never a good idea due to thermal expansion of the seam. It WILL crack sooner or later.

Rust conversion coatings never work as in my 25 years in this business I have seen them fail every time.

I painted the cab in the pictures in 1995 and told the customer I wanted to weld the seams as they were rusty. He insisted I sandblast the seams clean and pour DP epoxy primer into the clean seams. Then the seams were sealed with flexible seamseal from 3M. By 2000 some failure was evident and by 2005 he scheduled the truck for a complete redo.

Just my 2 cents