I had to blast that seam in my truck too. I then applied some "rust Mort" to kill any remaining rust . Then I sprayed that area with some DP40 "epoxy primer" and then applied some 3M seam sealer that I purchased in at the paint store. The next day I applied two coats of K200 a fill primer and that was it for the prep. It's been over 6 years and no rust bubbles have appeared so I guess it worked.


Joe