Best rear fender liner? - F-Body Road Racing and Autocross Forums

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 View Member Profile	Sep 29 2006, 01:38 PM Post #1
Seeking round tuits Group: Advanced Members Posts: 5,522 Joined: 24-December 03 From: Kentucky Member No.: 33	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?

CrashTestDummy View Member Profile	Oct 5 2006, 02:32 PM Post #2
Veteran Member Group: Advanced Members Posts: 3,888 Joined: 3-July 04 From: Pearland, Texas Member No.: 385	For road cars, my Dad used to spray the spray-on undercoating, and then, after it had had time to set, covered it with a couple of coats of semi-gloss black enamel. It seemed pretty durable, and the black undercoating wouldn't rub off on you when you were under the car. But then again, we weren't racing these cars.