Much more prep needs to be done before simply "bedlining" it. using a protective primer/rust converter coating like Chassis Saver is the way to go! That's what I'm doing.

I'm also looking into weld-thru primer (I'll be welding my 2x6 rockers in place), but see so many mixed things about it.

so what's the deal with these? ? any progress?

Not so much...busy with school and work, and when I can work on them the weather doesn't cooperate.

Just been driving around with my rockers cut out lol.

haha nice

I have used seymore's weld through, works great.

I would not recommend the weld through primer. Sure it sorta welds but you get more dingle berries then sasquatch.

And it's not gonna come out pretty.

I just put my ruffstuff frame stiffeners on and I was planning on using weld through primer. I cleaned off all undercoating on frame rails and sprayed with the weld through primer (before testing.. Dumb idea) tested it on a plate off the car. And I was not pleased. Been quite awhile so I don't have the picture anymore but tons of toxic smoke and an ugly weld to boot. So I mocked my stiffeners up penciled where wanted to weld pulled em back off and sanded that area down first then mocked up again and welded.. Lots of prep for Damn sure but should be fairly rust preventative.

Doing 2x6 rockers and uhmw boatsides next.

And on the bed liner. Curious where you get the notion that moisture will get trapped behind it?

Prep pre prep. All you need to do is sand it and rust reform any rust then sand again and apply. Unless your applying over water or doing a poor job of applying it why or how would it get water trapped behind it ?