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  1. #1
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    Jan 2006
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    So Calif.
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    Whats the best way to waterproof plywood-to use for truck be

    I want to permanently attach by use of bolts, a 4 x 8 sheet of plywood to the base of a truck bed. Needless to say, I want the plywood to be impervious to any water (truck is parked outside).
    What material do you recommend that I brush on ?
    I will either leave the plywood stained or perhaps have a coat of paint under this "brush on material".
    Any suggestions for an outer coat of something that will leave it water proof, yet withstand some occasional heavy objects.
    Thanks

  2. #2
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    RE: Whats the best way to waterproof plywood-to use for truc

    Best thing is to use marine grade plywood, then paint with an oil based exterior paint or finish with an exterior marine grade spar varnish/poly. Even CDX will eventually delaminate...FWIW.

    Dano

  3. #3
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    RE: Whats the best way to waterproof plywood-to use for truc

    I wood advise against the "bolting it down" idea entirely Woodrow, unless ya intend to put a topper (cap) on yer truck and leave it there, or ya live in AZ. (yer kindov secretive with no forum profile)

    Just recently a second friend of mine who had one of those plastic liners in their truck bed since new removed it after bout five years and found the weep holes in the bed had clogged and they had two inch rust holes where the weep holes had been.

    The liners, not being totally water proof allowed water, sand, leaves, and other debris to get underneath and without good airflow and sunlight to dry them, accelerated the corrosion process.

    Also, the areas where they drilled thru the protective paint film and plating (some beds have a cold galvanize plating under the paint - they expect you'll scratch em) to install the liner had corrosion creeping under the paint for an inch or more all round the holes. This is what prompted each friend to remove the liners and see what was going on.

    You may have noticed the same type of thing occuring on truck doors (an ugly bubbling under the paint at each mounting hole) where guys have had "west coast" style aftermarket sideview mirrors installed to see around a camper or large trailer and the sides of the newly drilled holes were not coated.

    Ive had the same piece of exterior grade fir ply (painted black to match the truck with whatever was cheap) just laying in the bed of my truck for 16 years. Yeah the ply has a slight curl to it, but I figure this helps promote drying underneath and has preserved the bed and ply. When I wash the truck I can easily slip the plywood outtov the bed and blast any debris away and let er dry.

    In 16 years Ive hauled machinery, broken brick and concrete, landscaping rock, sod, sand, and construction debris, and the plywood has had the snot beat outtov it, so unless yer hauling knitting yarn and cotton balls, I think coating the ply for weatherings sake is all in vain.

    The alternative to this (I think) would be a spray in bed liner like that "Rhino Hide", but now yer talkin buku bucks.

    I should qualify all this with the fact that I live in Minnesota where we quite possibly put down more salt per road mile than any other state in the union, (makes ya wonder where the environmentalists are) so you mileage may vary.

    My $.o2

    http://kgpetesgarage.com/images/sig.jpg

  4. #4

    RE: Whats the best way to waterproof plywood-to use for truc

    I think a marine grade of Plywood is definately a good idea.

    Another thing that happens in a Marine envirenment is that the plywood is coated with fiberglass. You can use just the resin without the cloth.

    Boats have been built with marine grade plywood for years. Maybe not so much anymore but there were planty and many are still with us. Often times with covered with nothing more than a good grade of marine paint. Woolsley, or Interlux are a couple of marine paints I can remember from the past. I am sure there are other good paints out there.

    I do not beleive Home Depot or Lowes will have any good choices in marine grade paint - and almost definately not marine plywood.



  5. #5
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    RE: Whats the best way to waterproof plywood-to use for truc

    I'd use pressure-treated plywood. You could paint it for a better appearance but it isn't necessary for durability.

    Cody

    He is no fool who gives up what he cannot keep
    for that which he cannot lose.



  6. #6
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    Louisville, KY, u.s..
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    RE: Whats the best way to waterproof plywood-to use for truc

    Two ways I can think of.

    1. EXPOXY Fiberglass resin, not polyester resin. EXPOXY is much stronger, mix a little non-slip agent and you'll be set.

    2. Hurculiner ( nock-off Line X ) about a hundred bucks will do both sides and keep it great for a long time.

  7. #7
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    Bradford, Vermont, MerryCanna.
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    RE: Whats the best way to waterproof plywood-to use for truc

    I'd strongly recommend using pressure-treated plywood and coating it with any of the good commercially-available paint-on bedliners like Herculiner or Rhino or that sort of thing. They were developed for just that job, and they do it very, very well. They'll withstand a truckload of rocks, if you're willing to subject your truck to it. They'll take a 350 four-bolt shortblock rattling around unrestrained. Ya can't say that about ANY of the conventional "wood" finishes.

    -- Tim --


    Work in the
    SHOP
    till you
    DROP

  8. #8
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    RE: Whats the best way to waterproof plywood-to use for truc

    I have to agree with Tim, if your serious about protecting your truck bed, get a sprayed on liner

  9. #9
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    Oct 2005
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    Myerstown, Pa.
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    RE: Whats the best way to waterproof plywood-to use for truc

    I'm with the Rhino Liner pool too. My first truck came from the factory with a plastic insert liner. It was slippery when wet and from it shifting in the bed it wore through the paint and rust started. Fortunately I caught it in time and some primer and paint took care of it until I sold it.

    I got a Rhino liner in the truck that I have now and am amazed at the difference. It's not slippery when wet and almost NOTHING slides on it. Yea, they're expensive but so is a new truck...

    If you're dead set on plywood I'd recommend the marine grade ply with fiberglass over top, or ya could take the plywood to a place that does Rhino or similar liners and ask them to spray a coat in it for ya. Jeff

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