Primers and Paints

[wndsnd]

What about using a good oil based exterior paint, thinned as a primer and then sealed with multiple coats over bare woods (Pine and Oak). Is it necessary to use Marine Products?

[landlocked sailor]

Kirby's, considered by many to be the gold standard marine enamel, is a linseed oil based paint, much like old fashioned oil based exterior house paints. No good reason not to use oil based house paint, except for nor supporting George. For that matter, many on this forum prefer to use latex exterior house paint on their boats. Rick

[Bob Cleek]

Well, I don't agree entirely with Rick's answer. He's right, Kirby's is darn good paint. The real question, as with any paint, is what your intentions are. If you want a primo paint job, then it is worth putting the relatively few extra bucks into good paint. If you are just slapping it on, it doesn't much matter. As for those who use latex house paint on their boats, well, that's their choice, but I don't think anybody who knows what they are doing is going to take that too seriously. For a workmanlike job, any good quality alkyd oil paint would be fine. Problem is, oil based quality paint is getting harder to find. At present, from a cost-value standpoint, Rustoleum is a pretty good compromise. If you are looking for a high gloss quality finish that you've put hours and hours into, then a quality marin paint is what you want. BTW, if you are using a gloss paint, do NOT just thin it as a primer. Gloss will not cover. Use the manufacturer's recommended primer until you have a perfect solid color, then lay on your gloss coats.

[Mike B]

wndsnd:

I would encourage you to review the FAQ thread in the listings, and especially this link:

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=001938

I chose to use a DuraMax Latex from Lowes..we'll see how it holds up to severe use in the river over the next year.

Mike B

[Lulworth]

I don't know about Kirby's paint but I will say that Cleek is right, rustoleum for $6.95 a quart is a great deal that seems as good as the interlux products (>$25 /qt) that I have used year after year on my 1953 Penguin. This boat is made of fir ply that even after all these years, still checks during the off (not racing) season, so every year I sand it down, prime with the interlux high build primer (I've not found anything as good) fill, sand, prime, fill, sand, prime .... then paint. This year I used Rustoleum and it looks fine (as fine as anything put down in cold weather can look). It only needs to last 'till the end of frostbite season and I'm happy.

David

[paul oman]

I would suspect the the best surface would be to coat the wood with a solven thinned epoxy primer (buy or make your own), either pigmented or not pigmented.

Epoxies are generally the primer under 2 part urethanes. I would think it would also work great with enamels too.

I have talked with boatbuilders that use solvent thinned varnish under their varnished surfaces too and the coating seems to hold up amazingly well so your suggestion probably has merit too.

paul oman
www.epoxyproducts.com/marine (http://www.epoxyproducts.com/marine)

[Don Z.]

Originally posted by Bob Cleek:
Santini has spoken...

[Wild Wassa]

My last edit removed my post, :( .

Epoxy seems to be a good primer across the medium when it has a good physical key and a hard cure. The different paint types (oil-based, acrylic and poly) and varnish (traditional or oil/poly blend) stick to it equally, I find. The marine oil/poly blend varnish is thin, all brands appear thin.

Varnish that I paint on old unsealed timber after wooding, my first 2 coats of varnish will be thinned with 50% turps. I reduce the solvent as I apply more coats. I also add a bit of oil to the top coat. It doesn't take much oil to slow the drying, a lot. I prefer a slow cure. This 500 year old technique of reducing solvent or increasing oil in upper coats with oil based materials to help longevity, is called 'thick over thin' or 'fat over lean' and something scientific. Underlying coats draw oil from the upper coats,

Don't let oil based paint go dry ... oil needs oil, often. A new coat rejuvenates.

Warren.

[ 11-04-2004, 03:25 PM: Message edited by: Wild Wassa ]

[JormaS]

I think it wholly depends on what kind of boat you have. An example: I have a heavy displacement 40 ft boat with caulked seams. I use ordinary house paint for the hull (oil paint). It´s four years since I wooded the hull, and I have only made small touch-ups each spring. I guess it will take two more years before I have to repaint the hull. But this is a "work boat" type hull - nobody expects it to look terribly yachty.

If it´s a nice yacht which stays in the water except for annual short haul-outs and it has glued or tight-fit seams, I would consider alkyd paint or two part polyurethane. The point is that if the paint will not tend to crack at the seams, then a hard and thick paint film is OK. A plywood hull also normally belongs to this category.

But if there are seams that have some movement for any reason, then a hard paint will crack and is a pain to retouch. It often ends up in fixing the cracks and painting the wole hull every year. Life should´nt be that hard.

As for latex, it won´t crack easily at the seams and the paint itself will stay on for many years, provided there is oil paint or a good primer underneath. However, touch-ups are difficult because latex does´nt take sanding (at least the ones I have seen). And when it´s finally time for stripping the paint, you have to strip every square inch of it.

In my view, by far the easiest and least costly choice is a good oil paint, if one can forgive it its general appearance and its lack of abrasion resistance.

[wndsnd]

Thank you for all that has replied, I have gained alot of insight into this application. HAs anyone used KILZ primer? They make an oil based product that is labeled for indoor/outdoor use. It might be a good oil base.

Thanks