Question regarding how to properly finish a hull

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MageDK
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Question regarding how to properly finish a hull

Post by MageDK »

I was wondering, once you have a boat what are all the different layers needed to finish the hull and deck, and in what order should they be applied?

I am looking at the 28' Trawler and plan on keeping it in the water here in Miami. So I imagine the hull will need a layer of antifoul paint. What about a UV protection coat?



fallguy1000
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Re: Question regarding how to properly finish a hull

Post by fallguy1000 »

Plywood and epoxy are faired and then painted.

Fairing is a process to make the boat sides and bottoms follow a fair line and not have ripples or waves.

Rick Laporte did a great video fairing a tw28. If you want to see it, I will look. Not sure it was any action.

After fairing, usually a mist coat of paint is done and more fairing to get to a perfectly smooth surface without waves.

Then epoxy primers are next. Epoxy primers are ultra high ashesion finishes used on the entire boat. My favorite is Interlux 2000e.

After the primer layers are applied, a sanding is done at least one or several times to get to 180-220 grit finish. Then usually, two part polyurethane paint is applied. It is a very hard paint applied just a bit past the waterline. After the topcoats are done, the boat is masked off to about 2"-5" above the waterline and the topcoat and primercoats are sanded and antifouling applied.

The choice of anti-fouling is usually localized, so in Miami, you'd need to go to a marina that is friendly and find out what people are using. A marina with a yard is best.
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OneWayTraffic
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Re: Question regarding how to properly finish a hull

Post by OneWayTraffic »

The amount of time you spend finishing a hull will be related to the quality of finish you are after. Regardless, any paint will do it's job of protecting the epoxy from UV. Above the waterline you could use latex house paint or expensive polyurethane. One will be more expensive and durable, but house paint is easy to apply and touch up. If you want to use an expensive two part paint then finish quality is important. A hard glossy paint will highlight every little mistake in fairing.

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Re: Question regarding how to properly finish a hull

Post by TomW1 »

Fairing is the most important step in the quality of your boat finish, especially above the water line. Below the water line you want a good fairing job with no high or low spots. But above the water line if you don't get a smooth fairing job every high or low spot can be noticed. especially as the quality of the paint goes up. Most people use a high level two part paint these days as it is longer lasting, but higher cost. My suggestion is buy the best paint you can afford, you won't regret it.

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MageDK
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Re: Question regarding how to properly finish a hull

Post by MageDK »

Thanks for the feedback all. It helping me plan out what and how to get everything done.

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Re: Question regarding how to properly finish a hull

Post by bklake »

OneWayTraffic wrote: Tue Jun 21, 2022 6:34 pm The amount of time you spend finishing a hull will be related to the quality of finish you are after. Regardless, any paint will do it's job of protecting the epoxy from UV. Above the waterline you could use latex house paint or expensive polyurethane. One will be more expensive and durable, but house paint is easy to apply and touch up. If you want to use an expensive two part paint then finish quality is important. A hard glossy paint will highlight every little mistake in fairing.
As of this morning, I am a dissenter on latex house paint. I am re coating a wood center console I made for my skiff. Most of the epoxy has peeled off on the outside but is holding strong on the parts out of the sun. I used some paint stripper on the exterior where the paint was holding fast. The epoxy under the paint is cloudy and brittle. I think I made this console ten years ago and it has been in the sun every single day since. I used white acrylic exterior house paint.

Not one to give up, I'm going to epoxy coat it this weekend but this time I'm going to put a coat of black primer on first then the white paint. I'll be back in 10 years with an update. I would prefer silver paint used to protect aircraft fabric but the only thing more expensive than boat stuff is airplane stuff.

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Re: Question regarding how to properly finish a hull

Post by Jaysen »

bklake wrote: Fri Jun 24, 2022 5:38 pm I think I made this console ten years ago and it has been in the sun every single day since. I used white acrylic exterior house paint.
That stuff won't last 10yr on a house. I can't imagine it should be expected to last that long on a boat. If I was using "not marine specialty" paint I would plan to strip/repaint every 2-3yr just like with varnish.

That said, my crappy prep, crappy applied, and beat-to-crap EMC paint is still sticking and hard to sand off (in the areas that aren't peeling due to dust between layers). I would suggest that no matter what paint you use, you're in for the same cost. It's just a matter of cash flow management
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bklake
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Re: Question regarding how to properly finish a hull

Post by bklake »

It's the same amount of work to properly apply any paint. Cheap paint that doesn't last or good paint that lasts a long time? That is a time vs. money question that only the person involved can answer.

My main observation on my console was that the house paint didn't stop the UV from degrading the epoxy. The paint peeled mostly because the epoxy failed. Underneath and out of the sun still looks fine.

The house paint was supposed to last 20 years. Said so on the can. Maybe I should have paid attention to the asterisk after that claim. Probably 20 ways that 20 year claim wouldn't be valid. Paint can long gone, no way to check.

fallguy1000
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Re: Question regarding how to properly finish a hull

Post by fallguy1000 »

Latex house paint is not even waterproof.

Ask me how I know.

All paints vary in adhesion and hardness and adhesion and hardness is what boat exteriors need.

Most latex house paints aren't even scuff proof, just sayin.
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Re: Question regarding how to properly finish a hull

Post by Jaysen »

Rustoleum porch paint refreshed every 2yrs worked to protect a FL14 pretty well. But that stuff is pretty hard.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

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