Inner Fender Coating??

decling

Senior Member
What if anything do you use on the underside of the fenders for rocks that come up off the tires? At what point in the restoration process do you apply it, clean metal, primed, painted, before or after? Do you paint over it?
In the area I live (no gravel roads) it seem like every trip rocks get flung up especially on the highway. I know the windshield and front there is not much you can do, but those are some big fender and running board surfaces that can get chipped.
Also, what do you use on top of running board? I have 3 grandsons and I want them to enjoy this when I finish, but I don't want to be hounding them all the time to be careful.


This is for my 38 1/2 ton truck.
 
The shop that painted my '40 uses GRAVI TEXplus under body coating. It can be sprayed or brushed and dries a light flat black.
 
On my '48 merc I sprayed the inner wheel wells, inner fenders, underside of the car and most of what won't be seen with raptor truck bed coating. the crap is virtually indestructible. btw I did this before the outside got it's guide coat. just my 4 cents worth(y'know inflation and all that)
 
I'm like Ken. I've driven my vehicles all over the country, on and off road, and I have never experienced a paint chip from a rock being flung up to the underside of a fender and chipping the paint. Maybe I'm just blessed. Undercoat was unheard of until what, late 50s or early 60s.

Just googled it, 1970s first practical coating.
 
Last edited:
And if you do get a rust spot under the coating it will fester until you see a bubble and then find a hole underneath.
 
I am in the "paint it properly camp" and then don't worry about it. The problem with the coatings, especially thick stuff like bed liner is, once you putt that stuff on, you will not ever get it off. It covers up nuts and bolts that you may need to access one day. It is not made to actually seal the underling metal and, as mentioned above, it may create a real perfect storm for rust.
 
Here-say aside I live in a rural area with gravel roads and driveways & have experienced rock chips from the tires flinging up pebbles on my 30 Roadster and 35 sedan.
I opted to use Herculiner on my 35 pickup project because it is a brush on product and I wanted a thicker coat.. The product used on my 31 Victoria was a spray on in a flat black and has a better look, a bit thinner, it seems pretty durable (may have been a 3M product)
From bare metal I used a black use epoxy primer then the black Herculiner.
I applied it before installing the fenders so the bolts were exposed.
 
You guys must run into different gravel; the kind I find "stars" the topside paint when it bangs on the underside.
 
btw the procedure for coating I use: 1) strip to bare metal,2) coat with rust reformer,3) epoxy primer,4) spray with bed coating. I've been using this method for years, so far, no rust bubbles or holes.
 
Back
Top