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Old Oct 02, 2008, 02:42 PM
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Water proofing boat interior question

I have a fiberglass hull with different types of wood epoxied inside for motors, rudders, etc. What do you use to waterproof the wood?
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Old Oct 02, 2008, 02:45 PM
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Quote:
Originally Posted by ken_nj
I have a fiberglass hull with different types of wood epoxied inside for motors, rudders, etc. What do you use to waterproof the wood?
Just brush on a coat of epoxy or polyester resin on the wood let it dry and your wood will be good. Alternatively, you can add a coat or two of enamel paint to water proof the wood.
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Old Oct 02, 2008, 02:48 PM
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Was looking to not mess with 2 part stuff. I bought a pint can of Perfect clear from the hobby shop which cost 10 bucks. The lid not not come off the can very well and would not seal and the paint dried up on me. Looking for something else to use.
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Old Oct 02, 2008, 06:49 PM
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Try hot fuel proofer (two coats) over the wood and then paint with enamel.
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Old Oct 03, 2008, 06:55 AM
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Thomson's waterseal should work also, you can buy a 12 oz spray can at Home Depot for $4.95, you won't have to get a gallon and have it sit around forever and then have to throw it out.
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Old Oct 03, 2008, 07:24 AM
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I actually haven't. Very little water gets inside, I had a bit of mould on my first boat, as I left eh hatches closed and she stayed damp.
Since then I always open the hatches for storage and the wood shows no sign of aging after a year.

The point I am making is that it only needs the lightest protection if any. The flip side is that if you may get rot if the wood gets damp and partial waterproofing allows it to get wet but does not let it fully dry. I think another memmber on here has had this problem.
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Old Oct 03, 2008, 07:58 AM
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My 4 foot PT has about an acre of unprotected basswood inside... no waterproofing at all, except on the OUTSIDE where it matters (fiberglass skin).
No problem.

I lacquered the inside of my tug, but just to make it look prettier.
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Old Oct 03, 2008, 10:00 AM
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I usually shoot the wood blocks with any good clear coat before I install them. I have used Krylon, Minwax Clear varnish, & Kmart's house brand among others. Just sand the area you will be gluing to the hull to remove the clear coat there. You can still spray or brush a clear coat on after installation but it can get messy.
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Old Oct 03, 2008, 10:44 AM
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I know you said you don't want to use two part mixes, but that is the best,most durable way to do it. I take 5 or 30 minute epoxy(depends on the size of the job) and mix the epoxy then mix that 50/50 with isopropyl alchohol. It thins out nicely and you brush it on like paint. It is not that messy, and the wood will never get wet. Wood WILL warp if it gets wet enough. Dennis
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Old Oct 22, 2008, 04:18 PM
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Would Minwax Water-Based Polycrylic be an option to seal those interior wood pieces?
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Old Oct 22, 2008, 05:59 PM
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Any of these sealers should work...

One point to keep in mind... Sealers not only keep moisture out, but they keep moisture in as well which is a good thing- I believe most processed lumber is dried to about 12% moisture content- which needs to be maintained to ensure long life of the product that it is made into-

Wood, depending on the environment it is stored in can dry out further and become very brittle over time if it is not properly sealed- I'm working on model boat "in the background" between other projects that is @50 years old-the interior was not properly sealed and as a result the wood, particularly the mahogany, was extreamly brittle to the point of barely being good for templates to make new parts...

For the sake of the future owners of your wooden boats, seal 'em well
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Old Oct 22, 2008, 06:11 PM
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Quote:
Originally Posted by dlapalme@cfl.r
I know you said you don't want to use two part mixes, but that is the best,most durable way to do it. I take 5 or 30 minute epoxy(depends on the size of the job) and mix the epoxy then mix that 50/50 with isopropyl alchohol. It thins out nicely and you brush it on like paint. It is not that messy, and the wood will never get wet. Wood WILL warp if it gets wet enough. Dennis
You're beter off to use one of the finishing resin kits like those made by Z-poxy, BSI Finish Cure, NHP, or Great Planes.
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Old Oct 22, 2008, 06:27 PM
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I dunno Aero... sealer will keep a splash of water from soaking in right away... but it is not waterPROOF! The wood will adjust is water content with local humidty, no matter what you coat it with. Just ask any furniture maker about the perils of cross-grain construction (a good furniture maker can look at a piece and right away tell if it will last 100 years...). I worked in air conditioning for a while... the thick rubber hoses we used, even with multilayer construction, still passed water right through... albeit at a slow rate, but we had to quantify the moisture ingression rate in order to calculate how much dessicant to load the A/C dryer with ('cause free water in the refrigerant will wreck the compressor).

From West System's site (my comments added):

Battling the forces of nature
When varnish is used alone as a coating, it is constantly fighting two distinct battles. One is to stay attached to a substrate that is expanding and shrinking as the moisture content of the wood changes. Seasonal changes in moisture content occur because varnish is not a particularly effective moisture barrier. When the wood changes dimensions, it forces the varnish to stretch and shrink in order to stay attached. Given enough stretch/shrink cycles, the coating will eventually crack.


The other battle is oxidation from exposure to the sun's UV light, a phenomenon that contributes to loss of gloss and cracking.

Good varnishes are designed to address both stretch/shrink cycles and UV degradation, but eventually the two forces in combination will break down varnish and cause it to fail.

The benefits of epoxy
Another method to achieve "the look" is gaining popularity and cuts labor time. Professional yacht refinishers now use WEST SYSTEMŽ 105 Resin/207 Special Coating Hardener as a clear base over wood trim before applying coats of varnish.


Three coats of epoxy followed by three coats of varnish can achieve the same depth and look of twelve or more coats of varnish. Because there are no solvents evaporating away from the epoxy, it builds thickness faster per layer than varnish and it doesn't shrink when it cures. In addition, three or more coats of 105/207 can be applied per day.

More importantly, sealing wood with an epoxy moisture barrier dramatically lessens (but doesn't stop!) its stretching and shrinking. Varnish benefits from being applied over a stable substrate. High-quality marine varnish is formulated with UV filters. So, the epoxy coating benefits by getting the protection from UV radiation that it needs. WEST SYSTEM 105 Resin/207 Special Coating Hardener and varnish complement each other synergistically. The two in combination last longer than each coating by itself.


The point being that you CAN'T stop moisture from moving in and out of the wood. The best I can do is lock the wood on one side with a layer of fiberglass, and then I just leave the other side open to "breathe".
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Old Oct 22, 2008, 06:48 PM
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I agree- You can't completely stop moisture from moving in and out... but you can slow it down... Making the wood as 'stable' as you can for long life is really the point... keeping moisture out prevents rot- keeping the correct amount of moisture in keeps the wood 'elastic' rather than drying and becoming brittle

Just think about all of those old, expensive Dumas and Sterling kits for sale on ebay... Think the dried, brittle, worthless wood found in those kits was that terrible when it was first put in the package 50 years ago? (ok, maybe the wood in the Dumas kit was! )

It is my opinion based on observation that sealing is better for wood structures in the long term- Most of us will probably sink or otherwise destroy our models before they are old enough for this to be an issue... but, for those models that remain, it may be a benefit...

And from the point of view of our small projects- sealing does not add a lot of effort or cost overall and at the minimum, keeps things looking nice...
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Old Oct 22, 2008, 09:30 PM
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Our boats\models will most likely out last us. Who knows where they will end up after we are gone, a museum, a shelf, the trash mountain? Will someone maintain them as much as we do? Probably not. And we hope they will not sink. Waterproofing the interior gives us the satisfaction that our masterpiece will not be damaged and is protected from the very same substance we are floating them in. There are many great suggestions and discussions about what to use. When I'm ready, not sure what I will use, but I will use something considered waterproof.
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