Best way to seal wooden hull

Discussion in 'Wooden Boat Building and Restoration' started by bubblehead620, Jul 1, 2014.

  1. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    I see from my original post back then, I did not show the hull side sealing.
    Here are 3 pictures
    First one is black pl partially sanded
    Second shows DAP on top, all you do is smooth DAP on to fill little imperfections, then sand a little. I used hand sanding in the seams, and random orbit 120 grit on the surface.
    Third shows it painted with one coat looking down the side.
    I did both sides the same way.

    I stopped past the toe rail. Water tended to cascade down the hull sides. This has kept it dry now.

    If for some reason, your sanding the black PL and it forms little tiny sticky rubber balls. Simply wet a cotton bath towel, and scrub the rubber surface with the towel and a water hose, and they all wash off.
    That happened in the high heat of a summer day back in 2014 close to 100 *F. But my latest sanding of the window frames, this did not happen in fall 2016 mid 60's temp.
    On the third day after smearing on the black PL it seems to sand fine. This polyurethane rubber is similar to 5200 which takes a week to cure. But what speeds up the cure could be spreading it so thin on the surface.
     

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  2. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    Window frame sealing with black PL and Dap Dynaflex 230.

    The black PL, this time I did some wet and dry hand sanding with 120 grit to knock off the high spots, then filled with some Dap Dynaflex 230 which I them wet sanded with 120.
    My sanding block, I used stick on 5" disks on a flat wood block.

    I also sprayed on some gray Rustoleum filler primer and wet sanded that.
    Got the surface very smooth and them primed with a Benjamin Moore alkyd, wet sanded again and I have rolled on Rustoleum Topside white paint.
    The Topside paint, I need to thin before rolling. So I will wet sand it first then thin and reroll. After 2 cots it looks ok, but has orange peel sort of look to it. I can tell it is a good quality paint.

    These pictures show it just with black PL ad Dap 230 partially sanded before any primers.
    Not saying this is easy, but I have seen benefits to sealing the wood this way, so I have been doing this.
    The area above these windows, I did the same way a couple years ago and has been fine.
    IF you do use these materials, you must use a primer under oil based alkyd paints, or the Dap caulk swells and get gummy.
    I like the water cleanup Zinsser Bull's eye 123 primer. It dries fast too. I used that primer under the hull side and the paint has stuck on well for several years, still looks new.

    (There are some dried leaves and debri from a storm stuck on these frames in the photos.)
     

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    Last edited: Nov 5, 2016
  3. JDM
    Joined: Dec 2016
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    Location: Austin Texas

    JDM New Member

    PL Material

    Just curious why you did not use white and maybe reddish PL. Mr. Newbie here
     
  4. sdowney717
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    sdowney717 Senior Member

    Store only sells the black colored version.
    They used to have a white window and door polyurethane.
    They do have a more liquid flowing grey concrete sealer designed to flow into cracks.

    Have a link or name to the red colored version?

    I have a lot of experience using the black roof flashing PL polyurethane.

    I have the swing open window in and painted and it looks and works good. Next time I get out there will take pictures and post.

    I top coated with Rustoleum Topside paint.
     
  5. JDM
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    JDM New Member

  6. sdowney717
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    sdowney717 Senior Member

    Yes, of course it would. Combine sealing and the top coat into one.

    Most likely that is going to cost a lot more money than what I did.
    Aliphatic polyurethanes are sun resistant, so a polyurethane exposed is going to have to be aliphatic not aromatic.

    Sanitred sells aliphatic and aromatic polyurethane coatings. Never have bought any of their aliphatic coating, did buy their aromatic coating. These coatings flow smoothly.
    http://sanitred.com/
     
  7. pauloman
    Joined: Jun 2010
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    Location: New Hampshire

    pauloman Epoxy Vendor

    sounds like black flexible solvent based epoxy paint then black latex paint over black epoxy

    call me at 603 435 7199
    paul - progressive epoxy polymers inc
     
  8. goodwilltoall
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    Location: nation of Ohio

    goodwilltoall Senior Member

    Sd downey, ps30 data sheet says not recommended for areas immersed underwater although, it passes 10 week immersion movement test whatever that means.
     
  9. sdowney717
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    sdowney717 Senior Member

    Of course not approved for the use. But it works anyway for me. I suppose Loctite does not want the liability issues. It has been underwater since fall 2014 and now it is spring 2017 with no problems.

    I did find that if you coat pine with oozing pine sap, it will not stick. Sort of a common sense issue though. I had one area above the water where it was having trouble sticking due to that. I had to scrape it off and clean the wood with a solvent.
     
  10. Windship277

    Windship277 Previous Member

    If you go with fiberglass, you are talking tons of prep work. Sanding to bear wood, applying 2 coats of thinned polyester resin of the laminating type. Then 2 layers of 1.5oz mat and then after all that work, 5 years from now, youll have probs with water ingress under the laminate. It happens every time. I dont know...seems wood is just wood and does what wood does. I never saw a lasting cure from fiberglassing over wood for anything but a small vessel. I didnt really introduce myself. Im a life long salt water sailor/power boater and was in the marine repair and construction for 25 years and owned my own marine repair and mod biz in Mass. Retired now. Largest power boat 36 foot. Largest sailboat 32 feet. Im a sailor at heart but anything just for a boat ride.
     
  11. Westcoaster2
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    Westcoaster2 New Member

    Sdowney, hi I would like to know how long you’re vessel is and how many tubes did you use below water line? How it working out now?
     
  12. goodwilltoall
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    goodwilltoall Senior Member

    Suggest if you are using more than a case of polyureathane tubes to go buy a sausage gun caulk dispenser. Much, much easier to work with plus, the sausages are 20oz. rather than 10oz. like the tubes and you pay about $10 a pc. so the cost savings pay for the gun ($70) right away.

    When buying PU, look for types which have at least 50% movement (forgot what those measurements are called but, there are two corresponding numbers i.e. 50/100%) the high end (still $10 per sausage) 1 part PU's now do what only 2 parts could only do a few years ago, they are available typically in 15-20 color varieties. Around here Sika, Tremco, Euclid, and 3M are the main commercial brands and all rate equally in price and performance.
     
  13. goodwilltoall
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    goodwilltoall Senior Member

    Just remembered Sika has a 2 part with good characteristics that you mix in a 1.5 gal. metal pail, it is the cheapest way to buy PU, prolly 25% of the cost of buying PL from HD and most likely better material or just as good. I think its $55 a pail.
     
  14. goodwilltoall
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    goodwilltoall Senior Member

    Btw, have experimented mixing epoxy with PU as well as with the Zinnser 123 primer.

    When mixed with PU it becomes the tackiest material i ve ever used.

    With primer, mixed 40% epoxy 60% primer and applied it after any glass work while epoxy is still tacky. It takes 2-3 days to dry but is extremly tough and can be sanded once dry. Tried it on a hatch for purposes of finding out if this will give epoxy UV protection.

    Found Zinnsser 123 primer to be excellent for use above water. Always try to apply it wet on wet with epoxy but a few areas had well set epoxy (few weeks at least) and it sticked to it even without sanding. Very pleased with it so far. When a mess is made just shake can, open, and apply.

    Used everywhere in engine room and for low lying /bilge areas will mix with epoxy. Its to work boat standards, many pro's would b horrified with appearance but wood is well sealed and will use saved time at interior living space for the where appearances really matter.

    With all this said, for anything below water i would not trust anything else but epoxy or PU/epoxy mix for perhaps UV resistence as well as for its toughness. Eventhough I despise working with it nothing else compares to epoxy for its waterproofing performance on wood.
     

  15. sdowney717
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    sdowney717 Senior Member

    Its is 37 foot long, it is a 37 Egg harbor.
    It is still doing just great, not a single leak.
    Last summer, I got in the water and scraped the hull clean of growth, was no problem cleaning it off, the Black PL was well adhered all over even going on 5 years now.

    It was also still sticking to the bronze rudders, just like when I went in back in fall 2014.
     
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