Undercoating repair (newer 911)?

[tubwreck]

I have a newer 911 which has this thick, resilient undercoating on the undersides of the rocker panels and the pinch weld. It is painted body color.

Ordinarily, rocks just bounce off this, or sometimes scrape off paint, leaving the white rubbery undercoating visible.

One particularly large and aggressive rock managed to take a chunk of the undercoating clean off, leaving some exposed (painted) metal.

I'm wondering if anyone can recommend a readily available product to repair this? I'm thinking about phenolic caulk?

The dealer referred to a product that costs $2000 per 5 gallon tub, "try a body shop".

[Luccia at Pelican Parts]

You could call a body shop and see what product they use or recommend. Or maybe try out this product recommended in this Pelican thread: Best product for matching undercoating on early 911?. Maybe some other Pelicans will have some additional advice for you as well. Good luck!

[FrenchToast]

Originally Posted by tubwreck

I'm wondering if anyone can recommend a readily available product to repair this? I'm thinking about phenolic caulk?

No caulk. You can get a rubberized undercoat product from Pepzone / Autoboys / Advanced-Nap(a) etc. Some dry harder than others. If you want the real deal Porsche stuff (without the 2k Porsche price), that would be from Wurth. I forget the exact name of it. You would have to special order it either directly from Wurth or a specialty shop.

Finish paint should be masked off. Surface should be lightly sanded and cleaned with a degreaser.

But, the pinch welds below the rocker panels get hammered. You are only going to get more chips.

If those are the lift points for a hoist or jack, then you can say goodbye to the undercoat and I honestly wouldn't bother until a lot comes off and you can repair it in bulk. Unless the only person who lifts the car is you, and done very carefully and with a special puck.

If you're just trying to prevent rust, an alternative is just to put some heavy paint on it. Then after a few months you can coat it in a heavy wax, i.e. cosmoline, paraphin, etc..

[911Cabrio]

SEM makes a 2 part urethane seam sealer. it can be purchased for about $30. Clean the area with a pre-cleaner and apply as needed with an acid brush. if you have specific questions, pm me. Bob