Removing Anti-fouling Bottom Paint Exposed Green Layer

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
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Landlocked
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Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby Landlocked » Mon May 22, 2017 11:09 am

IMG_5564 (2) (Small).JPG
IMG_5564 (2) (Small).JPG (183.16 KiB) Viewed 2779 times


Several years ago I bought my son this old 13-footer to use as a pond boat, and he's finally gotten the bug to fix it up. We flipped over the boat yesterday and went to work on what must have been at least five very thick coats of paint on the bottom--none of which were ablative. After a couple hours scraping and sanding, we gave up and brushed on some stripper. I Left him with instructions to wear gloves and glasses, keep the big barn fan behind him and the boat in front of him, and to get to work while I ran to the store for refreshments. Came back to [what is seen in the image above]. The hull is in great shape for its age, and he made quite a bit of progress in the 20 minutes I was gone--maybe too much.

What is the green layer pictured? Is this some type of barrier between the fiberglass and the original gel coat? Very thin and hard and sanding into the green exposes fiberglass strands.

The backstory: I got the boat and a very nice galvanized tilt trailer for $600. Trailer probably worth about what I paid for the whole rig so, no, I did not approach the project with a ton of research aimed at restoring the boat to original. Topside is not in as great shape as bottom. There is some water in the foam at the rear of the boat where a limb fell out of a tree and pierced the floor and was not addressed in a timely manner. Will address by boring holes, draining as much as possible, and then sealing back up. Floats fine now - Expect it to continue to for remainder of its life.

Keeping it a simple father son project - hope to just patch, prime, and paint with a decent quality marine paint. If he has gone too deep with the removal though, I would like suggestions as to what type of first coat or primer you guys would recommend or anything special I need to do.

His vision is to end up with a miniature flats boat complete with poling platform. Mine is to simply end up with something that floats and looks decent and has a solid enough transom to support the 20 Mercury I'm going to loan him for a couple years but do not want to lose.

Thanks

jimh
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby jimh » Mon May 22, 2017 1:22 pm

It is hard to tell from the image, so based on your description in your narrative--the green layer is "very thin and hard and sanding into the green exposes fiberglass strands"--it sounds like the entire gel coat layer in those green regions has been removed already, and you are now sanding away the lower layers of laminated resin and fabric. It is typical that the resin color used in the layers below the gel coat layer have a contrasting color, and green is a typical color seen in those layers.

Or, alternatively, you could have just removed the easier-to-remove layers of paint, and are now down to a very hard paint surface that top coats the gel coat. But, if you cannot sand through the green layer and hit white gel coat, then this is not the situation. And you've probably taken off all the gel coat in those areas that now show green laminate and resin.

Old gel coat becomes quite soft and can be abraded away very rapidly by sanding. If, indeed, you have removed large sections of the original gel coat layer, do not become too concerned. You just need to completely re-do the hull outer surface. You'll need to fair and smooth the surface, then apply some sort of water-proof top coating layer, perhaps an epoxy barrier coat. Then you use a high-built-up primer, sand, more primer, then new top coat. Work with a knowledgeable vendor who sells these products to select the right coatings for the various layers.

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Landlocked
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby Landlocked » Mon May 22, 2017 2:26 pm

Kind of thought that might have been the case. One point of clarification though, there was no anti fouling paint on the bottom. Just layer upon layer of very hard conventional paint. The newer top-coat was very tough to remove - may have been epoxy based. Not sure. Regardless, chemical stripper was the only recourse and once applied, all layers came off easily down to this green layer. The green itself I first thought to be a final coat of paint needing removal but it is very thin. If you sand it at all you expose fiberglass. there is no gelcoat underneath.

I'm not concerned - had planned on completely re-doing the hull anyway. Quite frankly, I thought it would be a bigger deal than it will be as I anticipated exposing significant hull damage when the paint was removed but none is present... As far as Knowlegable Vendors - West Marine is it around here as far as I know and they are a 45 minute drive away. Anyone got a suggestion for a product line to seal, prime, and topcoat? I can research online?

jimh
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby jimh » Mon May 22, 2017 3:04 pm

Based on exposure to relentless promotions, I have become familiar with the TotalBoat line. Check them out. Here is a presentation showing restoration of an old Boston Whaler boat on youTube:

https://www.youtube.com/watch?v=pUOlWPvgLfQ

They have many recorded presentations available. Sample a few at

https://www.youtube.com/channel/UCxOOQN ... XGOelphjdg

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Landlocked
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby Landlocked » Mon May 22, 2017 3:06 pm

Thank you.

jimh
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby jimh » Mon May 22, 2017 3:09 pm

Landlocked wrote:...there was no anti fouling paint on the bottom. Just layer upon layer of very hard conventional paint....


Most "bottom paint" is anti-fouling. It does not always have to be an ablative-type paint.

Now that the laminate layers are exposed, you certainly want to cover them with a coating of something that is waterproof. You have to keep water from being able to pass through into the laminates. The gel coat was the layer that prevented water from getting to the underlying laminate layers, but if that is gone, you need a barrier coat to stop water.

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Landlocked
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby Landlocked » Mon May 22, 2017 3:37 pm

A quick internet search for barrier coat returned several references to epoxy coatings and the trail inevitably ended back at West Marine. So, I will try and locate an affordable epoxy based barrier coat to apply on the bottom section where I have already sanded. The sides which are still white and the interior of the boat will be sanded more lightly and I'll try and forgo the stripper. Hopefully, once patched and faired, I can get by with the Total Boat Line "Wet Edge" for interior and sides above waterline. They have the seafoam green color we are looking for. I guess it will depend on how significant the repairs are when I get into them.


thanks.

Ll.

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Landlocked
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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby Landlocked » Mon May 22, 2017 5:48 pm

Not that it amounts to a hill of beans at this point, I just recalled the previous owner told me that prior to his painting it white, there was a lot of green paint showing and that the previous owner before him used it as a duck boat. Since I encountered no other areas of green, other than that shown in the photo, it would seem in hindsight that one of the previous owners had sanded it down to the green fiberglass epoxy prior to my son's well intentioned attempt to get as much paint off as possible before I got back home. Would not be surprised if I find the same concern on the sides, in which case, they too will get the new barrier coat. As far as the inside.... Starting to seem like a good candidate for Rhino lining!

Ll.

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Re: Removing Anti-fouling Bottom Paint Exposed Green Layer

Postby jimh » Tue May 23, 2017 3:20 pm

I think your inference that someone previously sanded right through the gel coat layer of the hull bottom is probably quite reasonable.

On these older boats that have seem some rough service and plenty of layers of paint, I don't think preservation of the original gel coat layer would be something easily done. With old, soft, brittle gel coat, there probably would not been enough thickness in the gel coat layer to abrade away all the scars and get to a clean, smooth surface.