Underseal for fenders?

[Bill Douglas]

Hi Guys.

What are you using for underseal of fenders? I'm mainly trying to keep corrosion out and have done the epoxy primer and Rust-oleum Rusty Metal Primer - which is meant to be good rust protection. I've done 3M seam sealer.

I'd like to use a Wurth product, but would like to hear of your recomendations of other brands and solvent/not solvent options.

[SalParadise]

My advice is not to use it. If you used a real spray on epoxy from a gun, it will be fine forever. Rustoleum is worthless after so many years. Problem is that undercoating hides what's going on underneath there, traps moisture, and then you don't know what's going on.

[wayne robson]

Sal paradise is correct, but i will ad to this,that if you under seal it
and you ever sell your Porsche , buyers will be suspicious,.
If i see underseal on a possible purchase i walk away.

[Bill Douglas]

Factory fenders have underseal. I wanted it to look factory. Or am I mistaken?

[wayne robson]

Yes Bill ,i know what you mean, but i am talking
thick black underseal, put on rough and 1/4 inch thick.
I have seen this on American cars for sale for years, and
they wonder why they dont sell,.

[911bruce]

The only time I have used the thick stuff was on my 32 Ford, it kept the rocks from "starring" the paint on the topside of the fenders. Other than that it usually makes one wonder what's going on.

[SalParadise]

The factory underseal is great if it's not compromised. The Wurth stuff in a can (that many of us, including me uses on gas tanks) is finicky out of the can at best. It does not harden any where near the factory original stuff.

I really don't know how many people try to replicate the factory underseal look for correctness. They mostly paint and leave it off.

I am sure people attempt this all the time and I am interested in what others say. But for me, I would never put it back on.

[SCadaddle]

It's called "Rocker Schutz".

[Dpmulvan]

You want to use Upol gravel guard or Chipgaurd. Rustoleum is crap, never use a rubber undercoat on any vehicle.

[jpnovak]

epoxy primer to bare metal
Upol Gravitex
then topcoat with automotive grade primer and paint.

[hun911]

I'm starting to undercoat my car with U-POL Gravitex. I have 12 Bottles. I hope it's enough! But i have a question. I've practiced a bit with the gun and i found that around 45psi and 15cm distance gives the right texture.
My problem is that when i spray the surface, everything looks really fine. But when it startst to dry it starts to get a matte finish and looks like the material starts loosing it's texture and flattens out. What did i do wrong? The problem is that i didn't see the original underseal texture on my '69 car, so i'm just guessing based on photos here in the forum.

My second question is that should i spray two layers? It looks to me, that if i spray the second layer an hour after the first, then the texture is more durable and doen't levels.

Any opinions?