Removing Varnish Stains From Nonskid Surface.

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
R DAVIS
Posts: 30
Joined: Thu Oct 22, 2015 10:33 am

Removing Varnish Stains From Nonskid Surface.

Postby R DAVIS » Thu Sep 29, 2022 3:05 pm

I have a 1983 Sport 15. The gel coat is in good condition except for some spots where a previous owner did a sloppy job of refinishing the wood surfaces and dripped spar varnish on the deck.

Q1: how I can remove the stains without damaging the non-skid gel coat?

Q2: how can i repaint the non-skid?

Q3: what products are effective in removing stains from gel coat?

Q4: is there a a paint who color is close to Desert Tan that is thin enough to not fill-in the factory non-skid surface?

Note: I have no intention of applying new gel coat or repainting the entire boat, or the interior, or the smooth parts of the interior. At most I will repaint the non-skid.

Thanks for any ideas.

MORE DESCRIPTION OF WHAT STAINS ARE TO BE REMOVED

There are numerous spots (maybe 50 or so), about dime size or smaller, and several larger ones, about silver dollar size.

The spots on the smooth parts of the gelcoat remove easily and completely using acetone or toilet bowl cleaner, and scraped off with a razor blade. The spots on the imprinted, factory diamond pattern, non skid surfaces however, are down into the non skin pattern texture (down into the diamond shaped texture), making it impossible to scrap away with a razor blade. I tried a small stainless steel wire brush along with acetone and toilet bowl cleaner, but it has no effect. I wasn't very aggressive with the wire brush as I didn't want to damage the non skid pattern. I don't want to try sanding it, as that will no doubt remove the texture. There are too many to try to pick out individually with a dentists pick etc.

I saw some products advertised to remove varnish, but some look to be rather harsh and might damage the gelcoat of the non skid pattern. There are some citrus based products on Amazon, but most of the user reviews say they are ineffective.

If I am unable to remove these stains, I have thought of simply masking and painting over the non skid areas. If I do that, I don't want to use any paint with non skid granules imbedded, as that would fill in the molded in factory non skid pattern, and although it would likely prevent a slippery surface, it would look terrible in my opinion, worse than just leaving the stains.

I would much rather just remove the stains than to mess with painting it.

macfam
Posts: 177
Joined: Fri Oct 16, 2015 9:24 pm

Re: Removing Varnish Stains From Nonskid Surface.

Postby macfam » Thu Sep 29, 2022 7:04 pm

Here’s a process that worked for me:

  • buy Franmar Soy-Strip Marine Coating Remover
  • saturate a few of the spots
  • cover with kitchen plastic wrap so the spots do not dry out
  • let sit over-night
  • add more if dried out
  • scrub with stiff brush
  • wipe with a towel.

This process worked well for me.

Franmar Soy-Strip Marine Coating Remover
https://eco-buildingproducts.com/product/franmar-soy-strip-marine-coating-remover-paint-stripper

R DAVIS
Posts: 30
Joined: Thu Oct 22, 2015 10:33 am

Re: Removing Varnish Stains From Nonskid Surface.

Postby R DAVIS » Thu Sep 29, 2022 9:09 pm

I just ordered a quart [of Franmar Soy-Strip Marine Coating Remover] for $22, but the shipping is $35 UPS Ground. Must be some powerful stuff.

I will try [Franmar Soy-Strip Marine Coating Remover], and in a future post I will report how [Franmar Soy-Strip Marine Coating Remover] worked for me.

I will just use a stiff bristle cleaning brush, and not use a stainless steel brush.

jimh
Posts: 10790
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Removing Varnish Stains From Nonskid Surface.

Postby jimh » Fri Sep 30, 2022 8:13 am

Please report on the effect of using the powerful cleaner-paint stripper had on the gel coat finish.

Q5: was there any damage to the gel coat?

Q6: what color is the powerful cleaner-paint stripper liquid?

The product seems intended to be used on hull bottoms to remove anti-fouling paint. Generally the hull bottom is not an area that is visible when aboard the boat. I have concern that use of this powerful cleaner-paint stripper might discolor the gel coat or otherwise affect its appearance.

R DAVIS
Posts: 30
Joined: Thu Oct 22, 2015 10:33 am

Re: Removing Varnish Stains From Nonskid Surface.

Postby R DAVIS » Fri Sep 30, 2022 11:56 am

I will try it on a small, inconspicuous area, and report on the outcome. It might be a couple weeks until I can do it.

R DAVIS
Posts: 30
Joined: Thu Oct 22, 2015 10:33 am

Re: Removing Varnish Stains From Nonskid Surface.

Postby R DAVIS » Tue Oct 11, 2022 1:00 pm

I gave the Franmar Soy-Strip Marine Coating Remover a try. It is colorless, odorless, and about the consistency of 80 weight gear oil.

First I dabbed a bit on a small spot with my finger. It didn't cause any burning or discomfort to my finger, and I washed it off my finger after a couple minutes. I left it on the non skid gelcoat, open to the air for about 5 minutes, and it barely started to soften the stain (the stain is actually a glob of spar varnish, about dime sized). Then I took a stiff bristle brush to the non skid finish. That removed some, but not all of it with a little elbow grease.

I rinsed that off, and then applied more on the spot, and let it sit for an hour with some Saran Wrap over it to keep it moist. Then I tried the bristle brush again, and while it removed most of it, there was still some down in the diamond pattern non skid. The bristle brush was just not quite stiff enough to get it all out. Then I tried mildly brushing it with a stainless steel brush, and that took it off, but left a very light stain on the gelcoat from the pigment in the varnish. A little Lysol Toilet Bowl cleaner on a scouring pad (after letting that soak for about two minutes) completely removed the stain.

I then tried a test area and let it sit overnight with the Saran Wrap. There was no sign of any softening of, or damage to the gelcoat, but the overnight soaking didn't do anything more than the one hour soaking did.

Using this product on the smooth gelcoat finish (the gunwales and the floor area without the non skid) made the varnish a little easier to remove with a razor blade than just the toilet bowl cleaner alone. Either way, a sharp, single edge razor blade held at a flat angle parallel to the surface, will just get under the varnish and it will pop right off with vey little effort.

The bottom line is that I am quite pleased with the product. I plan to completely clean the interior and floor of the boat using a combination of the toilet bowl cleaner, and the Franmar Soy-Strip Marine Coating Remover. I do have some trepidation about aggressively using the wire brush, so I will take it easy so as to not scratch through the gelcoat, or smooth out the diamond non skid pattern. That project will have to wait a month or so, until our south Texas weather cools down. I will try to remember to post some before and after pictures when finished.

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Removing Varnish Stains From Nonskid Surface.

Postby jimh » Tue Oct 11, 2022 3:57 pm

Thank you for the informative follow-up on the use of a Franmar Soy-Strip Marine Coating Remover for cleaning gel coat.

Quite incidental to your primary topic, I found this comment to be most interesting;
R DAVIS wrote: A little Lysol Toilet Bowl cleaner on a scouring pad (after letting that soak for about two minutes) completely removed the stain
This summer in northern Michigan a crop of small flying bugs grew up and were continually attracted to sit on the Desert Tan gel coat of my boat. I tried to get out every morning to rinse them off the gel coat, but my diligence was not perfect. As a result many of these small bugs died in place on the gel coat, and dissolved into little black spots which have stained the gel coat.

I have tried several cleaning products to remove these black spots. My favorite all-purpose cleaners, 409 or Simple Green, have not been effective at getting the stain out of the gel coat. I will have to experiment with Lysol Toilet Bowl Cleaner as a more aggressive solvent and cleaner for these bug stains.

R DAVIS
Posts: 30
Joined: Thu Oct 22, 2015 10:33 am

Re: Removing Varnish Stains From Nonskid Surface.

Postby R DAVIS » Tue Oct 11, 2022 7:58 pm

jimh wrote:I will have to experiment with Lysol Toilet Bowl Cleaner as a more aggressive solvent and cleaner for these bug stains.
Be sure to wear rubber gloves, long sleeves, and eye protection along with good ventilation.