eterior AC ply

Discussion in 'Wooden Boat Building and Restoration' started by soggy, Jan 7, 2010.

  1. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    The only caveat to that plywood is that it is made of Baltic Birch. Anyone around here will tell you that it will rot away as you look at it but I know that there are plenty of boats built of it in russia, scandinavia and the like. Maybe the fact that it doesn't get all that warm up there helps to prevent rot...I don't know. I personally am building a small 13 ft sailboat for my son out of it (nothing done yet because of sub-zero weather recently...planning on cutting wood next week though). I will certainly be sealing the surface plies and edge grain and the boat will be dry sailed...probably only a few times a year so I don't anticipate any issues with rot for a while.

    my $.02

    PS: Menards is a mid-west thing...he probably thinks you are swearing at him ;)
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Sorry about the localisms
     
  3. tkk
    Joined: Jul 2009
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    Location: Finland

    tkk Junior Member

    Experience shows that birch plywood is a lot more rot resistant than birch timber. Nobody seems to know why, but different theories have been presented. Traditional know-how in Finland said that birch should be kept off boats and used for furniture, but plywood has been used succesfully for planking boats.

    One example:


    I have started to build PAR's schooner using birch plywood. I will come back in ten years with some first hand info :D

    [​IMG]
     
  4. soggy
    Joined: Jan 2010
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    Location: comunist republic of massachuessettes

    soggy New Member

    Thank for all the information I was pretty sure it would work out ok but felt it would be better to ask before I spent money on a disaster. I never thought about underlay though and as far as getting the stuff I have sort of a running account with Fairhaven Lumber seeing as i'm there getting something or other 2-3 times a week. Pic will be coming as soon as the weather breaks so that i can start.
     
  5. souljour2000
    Joined: Aug 2009
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    Location: SW Florida

    souljour2000 Senior Member

    TKK,

    Good luck with that little schooner..I don't think you could have chosen many better ones to build than that gaff-rigger...the rudder looks very,very robust in its design.That boat looks like it could go just about anywhere in my IMHO...keep us posted please..
     
  6. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    Yes...the weather...projections for the next 10 days are for highs a bit above freezing and lows a bit more below freezing so I should be able to start cutting wood soon. I'll rip the sheets then bring them inside to lay out the panels then back out to cut. I could probably stitch the boat together but then I'll have to get different epoxy and/or wait until I have decent temps to do anything more on the hull. I can start on other stuff though. I should have already made the rudder and daggerboard but I work too much and I am lazy most times when I get home in the morning.
     
  7. switters
    Joined: Feb 2009
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    Location: Fort Collins, Co

    switters skiff


    Just looked at this same stuff at Lowes, agree with the above post. Would like to find some of the 5equal ply that was talked about locally.
     
  8. tkk
    Joined: Jul 2009
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    Location: Finland

    tkk Junior Member

    Souljour, I was just setting masonite boards on my concrete floor to start lofting. It is still really early phases.

    I had a go on casting the ballast earlier () because I spotted a cheap lot of scrap lead and I wanted to do it before winter. Need to redo it when the ground is thawn.

    Concerning weather, we had -28C last week:eek: , now only -4C. But my workshop has a steady +21C :D
     
  9. JLIMA
    Joined: Oct 2009
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    Location: New Bedford Ma.

    JLIMA crazed throttleman

    Ahh the wonders of heat, I have a nice little pot belly stove that keeps things nice and toasty when I'm working on something or other not to mention it's a nice way do dispose of that inevitable build up of scrap. Concerning the underlayment in MA I've never seen that 5 ply talked about earlier although if you do find some let me know where I may want to look into it.
     
  10. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    The stuff I have is called PlyFloor and has little green x's printed on it...to show folks who don't know how to nail...where to nail. Ruins the chance for a bright finish but it isn't the most attractive wood to start with (just plain white) so paint it is. You might try actual lumber yards for contractors rather than the big box stores like Home Depot or Lowes. Lots of times you can only find it in 5'x4' sheets. My local store (Menard's) only started carrying it within the last year or so.
     
  11. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    Please do not use any plywood made in China. You will have no idea who, what, where, and why what is in it.
     
  12. apex1

    apex1 Guest

    tkk

    the heat load when glueing the veneers to become ply, neutralizes the sugar content in birch wood, thats it.

    Regards
    Richard
     
  13. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    In protecting the ply from the elements, it sounds like the only portions of the wood that are epoxied are the edges and voids. Is this correct or do you try to encapsulate the plywood at all.

    I ask because most everything I've built, I go the full course with glass sheathing and encapsulation. There are times when I'd like to try an idea without the expense of a full bore glass and epoxy scheme. Upping the ply thickness and foregoing most of the glass makes for a great reduction in prototyping a design.
     
  14. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The idea that a void is enough to make plywood unacceptable is not really valid. Wood is more air than solid. It is made of a bunch of little tubes glued together to different extent depending on the species. That means that all wood is open at the ends, not just plywood with voids.
     

  15. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Gonzo,

    Maybe I was unclear. You mention glass taping the seams, but do you also epoxy coat the plywood or only epoxy the taped joints? Do you rely on the paint to seal the plywood?
     
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