Clinker down to bare wood What do I do next?

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Colin chandler
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Clinker down to bare wood What do I do next?

Post by Colin chandler » Tue May 14, 2019 9:16 pm

I've just been sanding and scraping my old clinker boat,
Should I use varnish or penetrating epoxy?
I like the look of it and just want a clear coating of something on it ubove the waterline any suggestions?
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barts
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Re: Clinker down to bare wood What do I do next?

Post by barts » Wed May 15, 2019 1:54 am

Varnish over bare wood is pretty high maintenance. Epoxy will of course need varnish or polyurethane over it to protect against UV. You may wish to consider Cetol Marine. My brother uses this product on the trim on his 42' ketch with excellent results.

https://www.sailmagazine.com/diy/cetola ... to-varnish

In any case, if the boat is stored in shade, your coatings will last much longer.

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Lopez Mike
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Re: Clinker down to bare wood What do I do next?

Post by Lopez Mike » Wed May 15, 2019 2:21 am

There has been some low intensity squabbling between Bart and I about Cetol v.s. other bright finishes. The good thing about Cetol is that not being quite so 'bright' it might look better on a less than perfect surface. Since you are dealing with some legacy imperfections that might be the right way to go. You think that your patches over the fastenings show now? Wait until you finish it bright of any sort!

Epoxy (I'm not a fan of thinning it) provides great water protection but it is usually done in conjunction with glass cloth and the same treatment inside the hull. Seal it up well and finally. And it needs protection from U.V. as well with varnish of some sort.

I think you would be better to stay with traditional treatments. A good oil based primer and top coat. I think that it will be better for the wood and be much lower maintenance. And easier to spot repair. Save your epoxy and varnish for places where you can gaze upon it fondly until you get tired of redoing it every season and paint over it anyway.

Just to make things clear, my new hull of marine plywood has been sealed on every surface with cloth and epoxy. The topsides finished in a one part urethane (bright blue) and the deck protected with varnish. My friends are taking odds as to how long it will be until I paint the deck.
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Re: Clinker down to bare wood What do I do next?

Post by barts » Thu May 16, 2019 2:31 am

Mike is absolutely right - the most durable finish for a stripped carvel/lapstrake boat is paint - something not too hard. Polyurethanes are subject to cracking due to moisture changes in the wood. If you want clear and you are building a epoxy sealed hull (inside & out), then varnish over epoxy is best. Traditional oil-type (linseed oil, turpentine + pine tar + some japan driers) finishes don't work well on all woods, but applied often can work well. It is subject to mildew, and requires frequent re-application, esp. if left in the sun. It gets darker with age, and smells really like a boat shop. The real win of the Cetol Marine is that it doesn't require stripping if maintained per instructions (like the oil finish), and is somewhat glossy and has mold inhibitors. It also requires attention. Our clear fir doors on our new house will likely get a coat of Cetol.

By the way, that turps mixture is great for iron work left outside (metal gates and the like); it's a traditional blacksmith's finish that lets the metal show through.

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Re: Clinker down to bare wood What do I do next?

Post by DetroiTug » Fri May 17, 2019 1:36 pm

For bright finishes which you are planning to do.

Over dry sanded smooth wood, I apply non=thinned West system epoxy. As Mike says, don't thin it with anything, it's not necessary and per the engineers that make it, they advise against doing that, on their website, they have a doc that states that. Epoxy never stops curing, messing with it's chemical make up, may cause it to become brittle or never cure fully for a hard finish.

To save a lot of work, dry brush the epoxy in to the wood, the first coat all that is needed is to have the epoxy soak in, do not leave a bunch of excess, it will just have to be sanded off back down to the wood surface, use paper towels to remove it if necessary. Do each coat the same way, all you want is a very thin coat wetting the surface, push the brush in hard and remove any excess. It may require 4 to 5 applications to build a smooth hard surface. Novice idea is to put on a heavy coat and sand it smooth, that doesn't work, areas where the grain is open will be low and grain is closed vise-versa. Makes a big mess to sand out.

Once smooth, apply Epiphanes varnish, it is the best varnish I've ever found, it's a little expensive, but far less expensive than having to strip the whole thing and start over in a few years. There is no such thing as a good cheap varnish. Two to three coats of varnish with light sanding in between will produce a very good finish. In the spring all it needs is a fresh coat of Epiphanes to restore the UV which goes on and flows very easy and you're good to go for the season.

If those screws are just filled with wood filler, ya need to take a 5/16 or 3/8" forstner bit over the top of each and bore down to the screw, then plug them with appropriate wood bungs, grain running the same direction. This sounds like a big job, it's not. If you try to do bright finish over those with white filler etc, it's going to look like polkadots with bright finish.

Those types of hulls are dificult to sand out. Take a board about as wide as your strakes and as long as your sandpaper and bore down on each end at angles the same way and put two large wood dowells for handles, makes a good two handle sanding block for sanding between coats. Keeps it flat, can't use circular rotary sanding discs under bright finishes, it will show up in the finish. If one wants that pretty bright finish, it takes work.

-Ron
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