Plywood boat paint

Discussion in 'Wooden Boat Building and Restoration' started by Old salty, Apr 2, 2018.

  1. Old salty
    Joined: Apr 2018
    Posts: 1
    Likes: 1, Points: 1
    Location: Florida

    Old salty New Member

    Hi I’m building a micro cruiser similar to Matt Layden’s little cruiser. I don’t want to use epoxy or cloth. Does anyone know what kind of paint and primer Matt used on his boat that protected it so we’ll ?
    John Theunissen likes this.
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    Salty, your post has been up for a few days with no replies. That is not the usual result of a perfectly good inquiry. Be that as it may, some of us do not know about Matt Layden's cruiser, certainly not what kind of paint or sealer that was used. Be assured that you are not being ignored.

    I am so old that I can almost remember what N0ah used for caulking. (pitch I suspect) I can tell you that in the olden days...not Noah days... we sealed the wood the best we could, first with a variety of fixit brews. That included such stuff as linseed oil mixed with kerosene or other hopefully penetrating and sealing goop. Way back in the day I used an oil based paint, thinned a bit with solvent, for the first or penetration coat. After that we used an oil based paint for the finish work. After the finish coat, some sort of anti fouling paint might be applied if the boat is to be left afloat. None of those desperate efforts kept the boat safe from teredos, rot, or other evil biologicals. They were better than nothing however. Sometimes we used a wood preservative like copper ------ (Pentachlorate)????/ ..I forgot the bracketed actual tech word. In any case you cannot even buy that stuff these days. It was nasty and toxic. Big brother is trying to protect us from our previous ignorance.

    Why are you not willing to use epoxy saturation and glass to protect you boat as best you can? Epoxy methods are far better than what we had, and were obliged to use, in the distant past. Epoxy/ glass does not guarantee that you will not have some future problems with your wood. If done carefully, according to directions, it will protect your wood better than most of the alternatives at the present time, and likely until you are no longer emotionally or fiscally attached to the boat you are building.
  3. Lepke
    Joined: Sep 2015
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    Location: Oregon to Alaska

    Lepke Junior Member

    If you don't use epoxy and cloth, you need to seal the wood first. Neither the wood or construction of plywood is as good as when it was made in the US. If you use cheap primer and finish without a sealer, it will fail. The plywood will come apart.
    I use thinned epoxy as a sealer and have no problems.
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    There are much better quality marine plywood available than anything ever made in the USA. For starters, american plywood was usually fir which checks badly. Thinning epoxy has been proven for decades to be a bad thing to do. It degrades the epoxy and makes it porous so it lets moisture through.
    Alkyd (oil based) enamel will give plywood a moderate protection. The old formulations had lead oxide which is a great biocide.

  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Gonzo beat me to it. A lot of folks think thinned epoxy or penetrating epoxy can be as a sealer on raw wood, but tests and time have long proven this incorrect and a waste of good epoxy. The most common penetrating epoxy brand is about 40% solids and 60% solvents, used as a vehicle. The vehicle evaporates, leaving the little epoxy it brought to the table. This doesn't seal much, certainly not the cellular structure in wood, so a further coating of 100% solids is necessary to complete the task, which begs the question, why use the thinned stuff in the first place. In reality, testing has shown (repeatedly) it's not the penetration of the coating, that makes things waterproof, but the quality of the coating (the 100% solids thing), that makes things waterproof.

    On some woods, like oily species, such as white oak, teak, etc. some suggest the above approuch, but (again) testing and time has proven this not to be the case, though there are pre-treatments that can help. I use a home made brew of acetone, xylene and toluene as a wash, that gets scrubbed into the raw wood, prior to straight epoxy coating. This will remove tannins and oils and prep the open cellular structure for application of goo. In fact it sterilizes the inside of the cellular structure, killing rot and mold spores, plus goo prep.

    These are also the same reasons why paints don't make things waterproof.

    To answer the OP's question, use a quality alkyd (oil) based paint, applying both primer and top coats per manufacture's instructions, which usually means a couple of coats of each as a minimum. It's not going to waterproof anything nor offer much protection, but you get what you pay for.
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