Basic Painting Questions

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Re: Basic Painting Questions

Postby marcusg » Thu Jul 25, 2019 7:34 am

Thanks. So is pretty much the only way to clean old paint off un-clearcoated laminate to strip it? I've done two applications of Citristrip and its working much faster on the clearcoated deck (which is almost done) than it is on the cockpit flooring/benchs/etc. I'm wondering if I should focus on sanding those or if that's too risky for thinning the laminate.
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Re: Basic Painting Questions

Postby GreenLake » Thu Jul 25, 2019 3:09 pm

You can sand "to" the laminate. If worried about strength, you can always add a layer of epoxy+cloth once you've sanded everything down.

More reasons to do all this work only when ready to do it well & complete.
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Re: Basic Painting Questions

Postby marcusg » Wed Jun 24, 2020 10:04 am

Okay, so after sailing my boat some last season, I've decided this season I'd quickly sand, fix, and re-paint it. Ha!

Yeah so...probably won't be sailing this season. There's a LOT of work to do. And that's fine. Plenty of free time with COVID and unemployment.

So here's where the boat is at now - in a large building that used to house 1500 chickens but isn't currently being used.

boat - back.jpg
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boat - deck.jpg
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I've CitriStripped and sanded the deck all around, and am still chipping away at the cockpit insides. CitriStrip, at least for me, on this job, was not a simple "do it a few times and it's all gone." I maybe have strippled 5-6 times on the most well done spots, and still some places are hard to get (particularly on the part of the deck that is "gravelly".) But deck is pretty much done, finally, although with a lot of help from my new sander.

As I get closer to the "repair" stage. I wonder about what this is? I'm assuming it was something meant to "fill" in the gap between transom and deck. Maybe there was some repair there, or a transom replacement at some point? It acts weird when I sand it - like the paint doesn't just come off, but sometimes digs in and swirls around some.

boat - filler back.jpg
boat - filler back.jpg (64.58 KiB) Viewed 320116 times
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Re: Basic Painting Questions

Postby marcusg » Wed Jun 24, 2020 10:06 am

Another question I have is the floor:

boat - floor.jpg
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boat - floor 2.jpg
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When I sand past the blue/white paint, I get to this gray layer. It's pretty thing so in theory I could paint or that, or would it be better to sand all the way to the fiberglass and then coat over that with some of the products mentioned earlier in this thread?
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Re: Basic Painting Questions

Postby marcusg » Wed Jun 24, 2020 10:11 am

The hardest part of stripping so far have been the cockpit walls. They don't seem to have any coating over the fiberglass, and they have this deep textured lumpiness (moreso than the deck) that makes it impossible to sand them without removing quite a bit of material. Stripping has kind of worked, but it's hard to get the stripper in/out of the deeper pock marks. I'm a bit concerned because I can see some broken fiberglass strands in there as I scrape/sand, so I'm not sure how to deal with it to not hurt the integrity of the boat.

boat - lumps far.jpg
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boat - lumpsclose.jpg
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And now...saving the best for last. As I was examining the underside of the boat to see if having a roller trailer hurt my boat (it did,) I found this, which wasn't caused by the rollers but maybe a rock on that crazy sail last year when we were getting blown around the channel. So I guess I'm gonna learn hole repair and have to deal with possibly anti-fouling paint after I do the "fun" part of repair and painting the topside.

boat - crack.jpg
boat - crack.jpg (68.35 KiB) Viewed 320116 times
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Re: Basic Painting Questions

Postby GreenLake » Wed Jun 24, 2020 7:33 pm

I've been experimenting with large-scale application of gelcoat. (Evercoat hi-bond, white, with wax).

I can only recommend that for your floor. Gelcoat is applied in a much thicker layer than paint, and is also more durable. It can be tinted, there are special tints that are sold, but as far as I can tell, a few drops of universal tinting agent (the one compatible with oil paints) seem to work just as well. It takes very little to get a nice gray color for a floor.

The thing about gelcoat is that by nature, it does not cure in the presence of oxygen. So you can get it with wax mixed in which will create a thin layer allowing the gelcoat to cure. That's not always perfect, so you get something called PVA, a liquid that you can spray (you may need to get one of the paint sprayers with a gas cartridge) on top of the gelcoat to improve curing. I think best time for that is when the gelcoat has started to cure, so it's not longer runny.

You can apply the gelcoat by brush, roller or just squeegee it on. For the floor, especially if your laminate is rough, you may not care about achieving a perfectly smooth surface, just a durable one. I only had a pint, which was enough to do the area from cuddy to aft of CB on both sides, and it's nicely uniform now and sealed many places where laminate had been exposed by something scraping on the floor.

I would recommend to fill any deeper gouges first - to remain chemically compatible, something like 3M high strength marine filler which is polyester based. (If you are careful washing off any amine blush with soapy water and then scuff sanding, gelcoat should bond to a bit of epoxy repair as well).

I know of professionals who will re-gelcoat a deck, so that can be done, but I might hesitate only because of the higher quality of the job expected for a deck: it has to just look good and I'm not as sure my technique is up to that. But for the floor, I wouldn't hesitate.
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Re: Basic Painting Questions

Postby GreenLake » Wed Jun 24, 2020 7:34 pm

West System and System Three both post guides on how to do epoxy / fiberglass repairs.
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Re: Basic Painting Questions

Postby Paddyt » Thu Jun 25, 2020 12:19 am

Hi GreenLake - I have seen you mention gelcoat for the floor a couple times. Can this go over a painted floor (after sanding/prep) or do I have to take it down to the original gelcoat before applying? I’m not looking forward to taking off the paint but like the gelcoat option.
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Re: Basic Painting Questions

Postby GreenLake » Thu Jun 25, 2020 2:38 pm

@PaddyT

I've applied gelcoat over "failed paint" after some sanding and scraping. I definitely tried hard to get all loose paint off first, but did not bother about any bits that seemed to adhere well. (In some areas, the paint adhered well over large sections, in others not so much).

My latest gelcoat experiment to too young to fully assess durability, but I've used gelcoat several years ago to cover places where the laminate had become exposed - surrounded by places which still had some paint adhering. I've not observed any of that gelcoat coming off, which encouraged me to experiment with a larger area this year.

My conclusion is that the gelcoat seems to adhere well to any of the still painted areas (that, of course may depend a bit on the particular paint). So, as long as the paint doesn't flake off and take the gelcoat with it, you might be OK.
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Re: Basic Painting Questions

Postby marcusg » Fri Jun 26, 2020 12:04 am

Greenlake, would you then also recommend clearcoat for on top of the walls/ceiling of the cuddy, where I mentioned its hard to remove the paint because of the lumpiness of the surface? And then not to worry about getting all the old paint out of the little lumpy divots?
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Re: Basic Painting Questions

Postby GreenLake » Fri Jun 26, 2020 11:43 am

Not "clearcoat" but gelcoat. ClearCoat is a product name of SystemThree for an epoxy especially designed for coating wood.

I would certainly be tempted to experiment with gelcoat on those walls (if I'm remembering the correct photo). The trick with gelcoat is to get it to cure when it's not the innermost layer in some mold (and away from air). On a smaller vertical surface like that I might be experimenting with some covering. You could just use plastic, but any crinkles would be imprinted on the cured surface. Perhaps some release fabric? Or sprayed PVA.

However, you can also just use a bit of a fairing compound to get any visually distracting roughness out and then paint normally. The benefit of gelcoat at the bottom of the cockpit is that it is impervious even to standing water, and will stand up well to being walked on, both requirements that don't exist for the upper inside of the cuddy. So far, the gelcoat that I have applied is low, in the center of the boat, where water will pool.

I can imagine using it on the parts of the cuddy going up or the walls of the cuddy primarily for continuity. I definitely wouldn't bother with the ceiling.
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Re: Basic Painting Questions

Postby marcusg » Fri Jun 26, 2020 3:22 pm

Any thoughts on how much I need to sand the lumpy walls/ceiling of the cuddy? Because of their lumpiness I can't clear them out completely without a ridiculous amount of stripping and scrubbing or by sanding them flat and thus removing a bunch of glass.
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Re: Basic Painting Questions

Postby GreenLake » Fri Jun 26, 2020 3:39 pm

Just apply a bit of filler before painting, you should be fine.
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Re: Basic Painting Questions

Postby marcusg » Fri Jun 26, 2020 3:43 pm

So should I bother sanding the sides/roof at all? Or just sand off the rough flakes?
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Re: Basic Painting Questions

Postby GreenLake » Fri Jun 26, 2020 6:23 pm

I would focus on getting the flakes off. And anything else that's not stubbornly adhering. If the surface was never smooth, sanding may not be the best approach - perhaps wire brush. One of the things that are hard to diagnose from afar. In a way, worrying about paint that doesn't want to come off should be lower priority then getting rid off paint that is already loose or can be persuaded easily to comer off. The former will probably provide a serviceable foundation for the next layer. (If painting, make sure you use a primer for the paint, and/or use a filler if you'd like to get rid of things like "weave pattern" from fiberglass cloth.
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