[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?

[sgarnett]

I had been under the mistaken impression that Herculiner required mixing in a catalyst. It's actually a humidity-catalyzed polyurethane, as is POR-15.

I used Herculiner on the bumpstop area, where the Duplicolor vinyl truckbed liner gets scraped off in even the most careful tire changes with 17x11.

I tested the Herculiner and Duplicolor on the zinc weld-through primer, and the Herculiner was both far more durable and had much better adhesion on the zinc, but as Rob said the Duplicolor is very easy to work with.

However, I'll probably need to do just a little more "fine-tuning" with the sledge, and I already know that a regular wire brush (not knotted) in an angle grinder goes through the Duplicolor like buttter. So, I used it over the zinc for now.

Once I'm finished hammering, I think I'll take the vinyl and zinc back off and use POR-15 (with their zinc phosphate metal prep) instead of the zinc primer as the base coat. Then the choice of top coat won't matter as much.