TheSamba.com :: View topic - Top restoration

Tue Nov 13, 2018 8:20 pm

I tried using Penetrol on my poptop. It was wonderful - at first

A year later, I added a second (heavy) application of Penetrol.
The next day, forest fires put a fine layer of ash and it stuck to the Penetrol.

Now it looks like H+ll. I need to strip the top.

How do I best remove the congealed Penetrol and trapped dirt?

So far, no success with the following:
- Denatured Alcohol
- Acetone
- WD40
- Simple Green
- Purple Power

Tue Nov 13, 2018 8:34 pm

I've used Floetrol, which is their additive for acrylic paint. Since Penetrol is an additive for oil-based paints, my first guess would be to use paint thinner. You said Acetone did not work, though, and that's a paint thinner. I'd suggest trying mineral spirits as well.

I'm not sure if you can get it in California, but it seems like everything I've touched with methylene chloride has come off. It's usually marketed as "Paint and Epoxy remover", like this one.

Tue Nov 13, 2018 8:43 pm

Penetrol is very sticky until it cures. It is well known that Penetrol should not be used:

1. In enclosed spaces without a respirator.
2. During windy conditions.
3. During times of pollen or other high particulate conditions.

But, if used correctly, it does a great job of restoring fiberglass gel coats.

OP... my guess is that you will now need to sand and repaint your top. Sorry to hear your troubles.

Tue Nov 13, 2018 10:43 pm

I used to be a sign painter and did my share of custom painting and have to be honest: there's no easy way out of this.

I used to use Penetrol to thin certain enamels for flow out, sometimes in lettering but more in roll-coating panels or big art.

One thing that should cut through it is Ez-Off oven cleaner, but I do not recommend it here for it's a bit of an art to remove paint with it without other damages.

Xylene would also cut through it, but is toxic as hell -- as is Ez-Off -- and this is too big a job for either.

I'd personally let it dry a month, block sand it smooth, and roll or spray with a couple coats of paint. Regardless of it not being designed to be a primer, in this case I think it would work great if properly sanded and topcoated with a compatible, oil-based enamel.

I suspect polyurethane would stick too but have never intermixed the two.

Tue Nov 13, 2018 10:45 pm

How to remove conjealed grease/oil/dirt/pollen/ash????

I'm giving this a try In the morning.

Tue Nov 13, 2018 11:45 pm

Ask Penetrol?

Wed Nov 14, 2018 7:25 am

I am not sure I would do a lot of trial and error on this one. The odds of you finding something that will makes things much worse before better are pretty good.

Wed Nov 14, 2018 9:06 am

pdm777 wrote: How to remove conjealed grease/oil/dirt/pollen/ash????

I'm giving this a try In the morning.

I dunno Bud, I know I said that might work but it's a huge mess needing a lot of tricks and masking and rags and pounding headaches (not from the fumes).

I used it to remove old painted stripes and lettering, but your job is hundred-fold that. The spray perimeter is where the problems begin.

Wed Nov 14, 2018 11:09 am

Too bad our resident Penetrol expert was banned! :twisted:
This sounds like your best bet though:
E1 wrote:
I'd personally let it dry a month, block sand it smooth, and roll or spray with a couple coats of paint. Regardless of it not being designed to be a primer, in this case I think it would work great if properly sanded and topcoated with a compatible, oil-based enamel.

Wed Nov 14, 2018 4:37 pm

RESULTS! The top looks Brand New!
Prior failed attempts included HD rubbing compound, polish,
solvents, and many fiberglass specific restroration products. All failed.

I didn't take a before photo, this photo is representative of the
dried out Penetrol, turning yellow and dripping like sap.

Step 1- Clean. Easy Off Oven Cleaner- mask for overspray. It's a gel so it stays put on vertical sides. Keep it off paint.Carefully spray a 2-foot area,
let sit 5 minutes, wipe off with -lots- of paper towels. The oven cleaner will liquify the Penetrol, messy but very effective! Keep wiping until ALL the Easy Off is removed. Rinse liberally with water.
Note the original texture is intact, and all the 'valleys and pits' are cleaned out of oxidized gelcoat.

Step 2- Wax.

Wed Nov 14, 2018 4:42 pm

That looks like a million bucks. Let us know how long the wax holds up.
Glad you found the right solution!

Wed Nov 14, 2018 7:35 pm

The oven's clean now, but where's our pizza? :lol:

Wed Nov 14, 2018 8:02 pm

Thanks to boating and woodwooking forums- they have been dealing
with Penetrol as as 'quick fix' for chalky gelcoats prior to sales. Removing
Penetrol is similar to stripping congealed oil/dirt stains from furniture.

Here is the recommended base wax, 3 coats over the Oven-cleaner-stripped-top.
(to be followed by quality auto wax+UV block and final buffing)

Wed Nov 14, 2018 9:53 pm

photogdave wrote: Too bad our resident Penetrol expert was banned! :twisted:

Oh goodness, this thread would be 12 pages long and full of contradictory rants.

Good work on the solution, OP! It looks great.