[sgarnett]

In the past, I've tried used several different rattle-can "rubberized" coatings consisting mainly of asphalt or vinyl. Neither is all that tough. The vinyl is a little easier to work except for some minor blushing issues (like laquer). The adhesion is probably a little better with the asphalt. Neither will dry completely if sprayed on thick, which isn't necessarily a bad property for a fender liner. However, I'm concerned that a thick enough layer of the vinyl (even built up slowly) may crack and allow hidden rust behind the coating.

However, in the past I've always been fixing a minor rub with minor hammering, padded by the original coating, that left the zinc plating intact. All I had to do was coat it with whatever was handy to prevent stone damage to the plating.

Recently I had some major rubbing on a sandy lot, with sand on the sticky tires definitely cutting through the plating. I also did some major hammering. So, now corrosion protection is a bigger issue. I already applied several coats of weld-through primer (first Wurth alu-zinc followed by U-Pol zinc, simply because I ran out of Wurth and can buy U-Pol locally). I definitely like the Wurth primer (even though no welding is involved) better than hardware-store cold-galvanizer paint. Adhesion is good on the Wurth, but I don't know about the U-Pol yet. Adhesion is poor on regular cold-galvanizer.

I'm thinking about trying a true catalyzed polyurethane truck bed lining, but that will be expensive and I'll have to waste most of it. I'm a little worried about adhesion (don't want to scrub the zinc primer too much), and it will be tough to repair if more pounding is needed. Brushing it on would be a big plus.

Thoughts?