I have the small patch panel for the side of the bed that just covers the area above the wheelwell and the lip around the top of the wheel well.

I am concerned about welding this panel in because there is no way to get to the back to prime/paint it the weld if its butt-welded, or put seam sealer on the back side of the seam if I make a flange and lay the patch into the flange and weld it. I've considered using an adhesive like 3M's duramix, but its another 100 bucks for the adhesive and the special gun. Meanwhile, a buddy has a MIG welder and is actually good with it.

Any suggestions on the best way handle the preventative aspects of the repair in keeping the back side of the weld/seam protected against future rust?

 

To avoid future rust, remove the steel inner wheel well. This is the piece that is welded to the bedside. A lot of dirt and crud gets up in there and causes rust. Look at the bottom of your bedside, you will see rods attached to the bedside and run back to the inner bed. They give the lower bedside support. Fabricate a few of these and use them on the wheel well. Then fabricate a piece of plastic for the inner wheel well liner, and attach it to the rods.
No more dirt and crud getting stuck up in there.
As for attaching the panel, do a search on this forum under panel adhesive. It was discussed in depth. Someone found the gun and adhesive for a lot cheaper.
If you still don't like the price of the adhesive and gun. You can do this. Prep your panel and flange your piece. You can use windshield urathane. This is what they use to install windshields.
It costs about 12 bucks. And fits into a standard caulking gun.
Apply urathane to your panel, and while the urathane is still wet, drill and pop rivet the piece in place. Do it while it is still wet, because the urathane will get around the rivet and in the hole you drill. The rivet will never get loose.
It takes over night for the urathane to dry. So you have plenty of working time.
Your first coat of filler should be kitty hair bondo. This will give the seam strength. Then finish off with regular bondo.
Wear surgical gloves when applying urathane. That stuff is hard to get off your hands. It can get messy.
After your done, undercoat the heck out of it.
zanny

 

hey sigtauenus
where did you get that patch panal from or is it possible to get them because my truck is doing the same thing and I hate it.
thanks 77blueoval

 

NPD is a good place to go, good prices, good service, and a great catalog, and much better than the "evil" place not allowed to be mentioned here.

 

EASTWOOD SELLS A PRIMER THAT CAN BE WELDED ON.
YOU CAN PREP THE PATCH PANEL ON THE BACK SIDE AND
WELD IT IN.