Bed Rot Repair Part Deux

So I recently posted about a small bit of bed rot that I had starting on my passenger side wheel well. I found a guy who did a good job on the top side work and then Line-X'd the bed. He mentioned the rust had only gone full thickness in one tiny spot, and that he had treated the bottom side too; I didn't dig too deep because I was prepping for a trip to Colorado.

A couple days later I got under the truck to grease my U-joints and suspension and found his work was kind of sloppy on the bottom. I noticed a slight gap between the bed and fender sheet metal and I figured water was going to get in there and start the whole rusting process all over again.

So, here was my take at repair until I have time and space to remove the bed. I started by masking off around the problem area and stripping the factory rubberized undercoating on both sides of the seam with acetone and a wire wheel Dremel attachment:



The gap can better be seen here. My welder should have removed this coating and welded from the bottom side too. I'm guessing this would have required him to take the bed off and then the job would have gotten a lot more complicated/expensive.



I cleaned the general area as well as I could with cleaner/degreaser and then treated with acid etch, then coated with three coats of POR-15. This was complicated by the fresh Woolwax I had applied - it was expensive and I didn't want to fully remove it.



After letting the POR-15 cure, I scuffed lightly with 320 grit and then applied 3M 1K urethane seam sealer over both sides of the seam. The first bead I tooled into the joint using solvent to extend the open time, then I applied a second bead directly over the seam. After letting the seam sealer cure, I sprayed three coats of rubberized undercoating and then a couple coats of rattle can paint. Final result:



Not the prettiest, but I'm hoping it will be good enough until I can pull the bed and rework this spot. What do ya'll think?

 

Looks good to me.
Looks like an effective way to keep the water out.

 

Nice, thanks! It was my first attempt at this kind of work and it went a lot better than I was imagining it might!