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Primer for exterior hull and floor

Posted by trouter12 
Primer for exterior hull and floor
February 27, 2019 12:14PM
Hello,

I am planning on finally finishing the boat this spring and was wondering if you guys recommend using a primer between the epoxy and the exterior hull paint and on the floor. If so, what would work. I plan on painting the exterior dark green and the interior light gray. I live in NY so some of the oil based stuff is harder to find but I don't mind taking a trip to Vermont or PA if needed. There is a West marine in Albany I can go to if needed but would rather hit a Lowes or Home Depot if possible. I figured I could find this answer in the search function but surprisingly it didn't pull up much. Thanks - Eric
Re: Primer for exterior hull and floor
February 27, 2019 01:18PM
Eric:

Thank you using the forum instead of email.

I choose the paint first and then go with appropriate primer, best matching that paint (yes you do need primer under paint).

I've never used water based house paint. It's not particularly durable but it's easy to work with and easy to touch up. I've seen a few old boats coated with water based house paint. But never done it.

I have used oil based house paint. It scratches easily but it's also easy to touch up, with a brush or with a spray system.

Petitt Easy Poxy Paints (and others like them from various boating outlets) are not in any way epoxy, they're extra high quality alkyd house paints. Petitt can be sprayed or brushed (or rolled on and tipped off with a brush). It's very good stuff for the price. The ony drawback is the lack of color choice. Petitt only offers about a dozen highly saturated colors. You can buy an auxiliary can of white, in order cut the intensity of their dark dark blue red or green. It can be tinted at the local paint shop too. The guys there hate to do it because they're not following a recipe and they get nothing out of it. But it can be done. It cleans up with paint thinner or better yet Naptha.

Automotive paints have to be sprayed. Automotive paints take considerable experience and skill to work with properly. But it is good stuff. When it gets dinged you have to spray to patch it. The chemicals involved are toxic. You need an expensive carbon element mask to work with it. Professionals, who work around it on a daily basis, are encouraged to wear forced air breathing masks. I like the iridescent metal flake hotrod paints. In any one of a zillion color combinations.

Marine paints (two part polyurethanes) are, I think, little more than extra expensive versions of automotive paint. Some marine paints have "anti-fouling" chemicals built in but that's only for the salt water market.

Water based floor finishes are getting more durable all the time. I don't know anyone who has tried it as a boat finish. I finished hardwood floors for a living for a few years, 25 years ago. The solvent based polyurethane floor finishes were more durable then. Still are. But they're toxic as hell and the water based stuff was almost but not quite as good.

The water based floor finishes continue to improve. Someday I'll try it on a boat. Even with water based floor finish you start with one or two coats of a (clear thick syrupy) primer layer. And then finish with two to four coats of a thinner clearer-yet finish material.
Re: Primer for exterior hull and floor
February 27, 2019 11:40PM
Thanks - I appreciate the info-
Re: Primer for exterior hull and floor
February 28, 2019 03:50PM
I take one point back. Petitt paints are not so cheap. Their price per quart is almost as high as automotive paint, especially so when you figure the shipping. Automotive paint you can buy downtown.

The main advantage of high quality alkyd paint (like Petitt) is not being forced to spray. I have almost $1000 dollars invested in spray equipment. And then it took a bunch of expensive and failed spraying episodes to learn how to use it.
Re: Primer for exterior hull and floor
March 02, 2019 08:41PM
I think I can get the result I want doing a roll and tip.
Thanks-
Re: Primer for exterior hull and floor
March 04, 2019 04:19PM
Hey guys-

I was just looking on the Raka website and saw they have epoxy pigments. Has anyone just added pigment to the last coat or two of epoxy instead of painting? I put graphite in the last coat of epoxy on the bottom of the boat and about 6 inches above the chine and it looks pretty sharp. If I could get the right color with pigment and then go over it with varnish wouldn't that probably work better than paint? What do you think? Thanks - Eric
Re: Primer for exterior hull and floor
March 05, 2019 01:50PM
......I've seen pigments there. Never used them. You could get a small bag and make an experiment. Tell us the result.
Re: Primer for exterior hull and floor
March 12, 2019 11:29PM
I just ordered the pigment and a few other items to finish the boat - I will give it a try and and let you guys know how it goes. I think that as long as I can get a solid color it should work. I figure that the worst that can happen is that I don't like it and then I can paint over it. I got a few different colors as I want the exterior dark green/brown and the interior an offwhite/tan with the gunwales and some accent pieces bright wood.
Re: Primer for exterior hull and floor
March 13, 2019 01:49AM
Send us a photo. Cell phone. What ever you have.
Re: Primer for exterior hull and floor
March 17, 2019 07:50PM
System 3 sells epoxy pigments, but their instructions specify that these do not provide protection from UV degradation, and that clear top-coating is required to protect the epoxy from sunlight.

You may wish to check with the Raka folks on whether the pigments they sell provide UV protection.

Also, you may want to search boat painting with latex house paint. There are a number of threads on this topic.

The bottom and exterior of the boat I currently have under construction is painted with Benjamin Moore Aura exterior acrylic house paint - semigloss. Not as hard or as glossy as Pettit EZpoxy, which I have used, but application was much quicker.

EZPoxy needs scuffing or sanding between coats. On my dory I have six thin coats, with a day between each, plus time for the scuffing and sanding. Very nice paint job, but took in excess of a week.

Acrylic (latex) house paint - two coats, one per day. No sanding. Paint looks fine.

I've never completely got the hang of roll and tip. Tipping always leaves a few brush marks. So I have just rolled using those 1/8 inch nap Wooster yellow foam rollers. I get mine from System 3. With a thin paint coat the finish levels fine using those rollers.

The advantage of the water based house paint is no solvents used in thinning and cleanup is way less messy. Paint is a bit less expensive and color selection is nearly unlimited. Less gloss will hide imperfections. Higher gloss and darker paints show more imperfections.

There are trade-offs with each paint type.
Re: Primer for exterior hull and floor
April 05, 2019 10:56PM
Raka UV Invibited Epoxy holds up pretty well. I assume that pigmenting it would make no difference to its UV capabilities. I wouldnt hesitate to use it as a final coat. Might look really sweet swirled in randomly.... Cool idea vs standard paint. The automotive paints are so good and easy to work with though, Im not sure why Id try anything else.
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