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PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 12:32 pm
by Tom Donnelly
Excellent information on the 'Before I Paint' thread. We primarily drive gravel roads in our area and would greatly appreciate any suggestions, techniques, or materials, to achieve optimum durability for painting the under-side (road side) of new metal? Thanks in advance!
Re: PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 12:34 pm
by pron022020
Don't cheap out is my advice. Good coat of a good epoxy primer holds up very well and top coat it woth a good paint.
Re: PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 1:08 pm
by John kuehn
If you are going to drive your T a 2nd coat of paint for the underside will help. Keeping a T authentic would require a coat of paint on the sheet metal underside and that would be it.
I’ve bought some fenders and drive train parts to restore and either they were under coated years ago or the T drove of a road that had been worked on and re black topped.
Re: PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 1:37 pm
by Rich Eagle
Everybody has their favorites. I have had very good luck with Enamels. Dulux is no longer available but Rust-Oleum and Van Sickle have worked well for me. I have 20 year old paint that cleans up well using those paints. A little oil blow by helps preserve it too.

Enamels don't dry as hard and resist chipping better than some of the harder paints.
Just my 2¢.
Rich
Re: PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 5:43 pm
by Allan
On the under side of the flat fenders on my 1912 van, i used the same material as used on modern car rocker panels. It is made for such applications. From memory, I thinned it a little more than recommended to make it a smoother finish, still just a little textured, but with a good gloss finish on the paint work, it is rarely noticed by observers.
Allan from down under.
Re: PAINTING THE UNDER SIDE?
Posted: Mon May 09, 2022 5:46 pm
by Steve Jelf
It's not original, but I think I will use rubberized undercoating on the bottom of my fenders after painting. It's available from Rustoleum, 3M, and others.
Re: PAINTING THE UNDER SIDE?
Posted: Tue May 10, 2022 12:10 am
by Allan
That's basically what I used Steve. By sticking with automotive finishes, you will have no problems with incompatibility between products. The stuff I used was made to be topcoated with whatever was used to paint the rest of the car.
Allan from down under.
Re: PAINTING THE UNDER SIDE?
Posted: Tue May 10, 2022 8:37 pm
by Larry
Sherwin-Williams Automotive produces a single stage urethane enamel product called “ Genesis G2”. It is an industrial coating that dries very hard and is not supposed to chip. It is used by trucking companies where appearance and durability is required.
I’ve been using it on the underside of Antigue auto fenders for several years. If you’re restoring a show car and plan to cut and buff the finish, I would suggest you do it within 48 hours as it will be too hard to do so after that.