need Marine grade Plywood...

Discussion in 'LOCAL OHIO TALK' started by dinkbuster1, Nov 17, 2009.

  1. dinkbuster1

    dinkbuster1 New Member

    cant seem to find small sheets of marine grade plywood in the Dayton area, only thing i can find is 4x8 sheets at $100 a sheet!

    need a couple small pieces for a 12ft jon. willing to drive within 50 miles if anyone has a couple small pieces to spare or sell cheap!
  2. fishmonster13

    fishmonster13 Member

    you can order marine grade plywood from, i think either home depot or lowes. if you can't find some use regular plywood sealed with epoxy you can order epoxy from us composites i used their epoxy and its pretty good and inexpensive as far as epoxy goes. the 16oz 3 to 1 kit is $14.25 and should be plenty just mix it up and roll it on the wood like paint make sure to get all sides

  3. MRR

    MRR New Member

    I treated my reg 1/2 plywood with that Kiltz then painted it the color i wanted.Long as u keep it in good shape should n't have any problems.
  4. playin4funami

    playin4funami New Member

    Saronville Ne.
    just use regular pressure treated ply but buy a bottle of that treatment crap and paint it on the cuts edges you make,lasts for many years. Or even treat whatever you use with thompsons water seal. Or, go with the plastic wood stuff,never rots! Really when you ask for marine grade all your getting is pressure treated at a higher price anyway.
    Last edited: Nov 17, 2009
  5. Catfishboy1995

    Catfishboy1995 New Member

    Council Bluffs
    i dont know if it is any thing close to what you looking into because it is pretty pricey but im not sure the price..but i would look for a sheet of like composite might be expensivei dont think it will be a 100 bucks a sheet though!!
  6. smokey869

    smokey869 New Member

    when i re decked my pontoon i priced the marine plywood, then talked to a guy at the marina and he showed me that it was only required for saltwater, he said they only used treated, which is what i went with then sealed it no problems so far and saved me about $300.00
  7. Catfish_Commando

    Catfish_Commando TF Staff Member

    Mark J did a good piece on Marine Grade Plywood, it was some good info.

    See if we cant get him here to recap on it.
  8. Mark J

    Mark J New Member

    Four Oaks, NC
    I'll give the short version because you can write a book on marine plywood.

    First question is what do you think marine plywood is? If you think it is some awesome wood that doesn't rot very easy you would be wrong.
    Second, I don't have a clue what your need for marine plywood is in a jon boat but at 100 bucks a sheet it sounds mighty thick and heavy.
    You can get 1/4" marine ply for 40 bucks a sheet plus shipping.
    There are all kinds of marine plywood.
    You got a couple of grades of Meranti like the 6566 or the 1088.
    You got fir.
    And you got Okoume to name a few.

    Okoume is about as expensive as it gets typically without going to some of the Sapele's

    What makes marine plywood marine plywood?
    It's strength.
    It's weight.
    It's lack of voids in the inner plies.
    The glue that holds the plies together.

    Your marine plywoods are for the most part manufactured overseas with the exception of fir.
    I know of only one brand that is treated against rot and it's a minimal treatment that still requires encapsulation.
    In fact the species of trees used in these offshore manufactured marine plywoods are rain forest trees. Those trees typically aren't as rot resistant as southern yellow pine or white oak.

    Why do we use marine plywood building boats then?
    Refer back 2 paragraphs to what makes marine plywood marine plywood.
    It's a strong lightweight panel.

    The biggest misunderstanding about marine plywood is that it doesn't rot.
    It does without encapsulation using epoxy. YOU HAVE TO ENCAPSULATE marine plywood.

    Not sure if the plywood you have is marine plywood or not?
    The reason I throw this in here is because you are looking for a small piece of it. Marine plywood is stamped with a BS (British Standard or Lloyd's) stamp.
    It's a proof stamp. Your small piece may not be the piece with the stamp.

    One way to find out. Take a piece and cycle freeze it. Freeze/ thaw cycles.
    Throw it in a pot of water and boil the piss out of it and freeze it again.
    If it doesn't delaminate chances are high you got marine plywood or atleast plywood with the same type of glue.

    Working with marine plywood is a joy. Once you ever work with a piece of Okoume EVERYTHING else in the world of plywood is inferior. It bends, cuts, and shapes well.

    If you ever get a piece of marine plywood in one hand and some pine plywood in the other hand you'll readily see and feel the difference.
    The domestic plywood is full of voids in the laminations and the inner plies are junk wood.
    Not so in the marine plywood.

    Weight differences?
    1/4" southern yellow pine is about 24 pounds a sheet.
    1/4" Okoume has twice the plies and is completely solid with no voids and weighs in about 16-17 pounds a sheet.

    3/4 treated plywood weighs average of 86 pounds a sheet.
    3/4" Okoume hovers around 50 pounds sheet.
    Doesn't sound like alot of difference until you build a boat that takes 25 sheets of plywood.
    It can make the difference of powering it with a 150 or 90 real quick.

    As an example of it's strength to weight ratio. My next boat is a 20 foot center console that will weigh 1400-1600 pounds when it hits the water.
    It's construction is 2 layers of 3/16" plywood glassed inside and out.
    It's powered with a 90 horse 4 stroke which is plenty adequate.
    A 70 would plane it. We're talking GPS'd at 42 MPH with 5 adults onboard.
    It's not your typical 20 footer. It's a big honking 20 footer. Capable of running offshore. Huge carolina flared bow.
    That is where marine plywood shines above all others.

    That is pretty much the short version boss.
    Last edited: Nov 18, 2009
  9. dinkbuster1

    dinkbuster1 New Member

    WOW! that was a great piece Mark! think i may have found someone here locally that has a few spare pieces to give me. i dont know if there was "marine grade" wood on there before or not, i am sure it was original and was totally rotten. on my bigger boat i did use "treated wood" when replacing the transom wood. it worked out but was unsure if it was the right thing to do. thanks a bunch, i just got schooled :wink:
  10. Mark J

    Mark J New Member

    Four Oaks, NC
    For a transom board for smaller engines I don't see anything wrong with treated plywood.

    Building a transom on a boat it would be a real poor choice because of the quality of plywood. It's not nearly as as strong as marine plywood.
    In the Virgin Islands the roof on a house will almost always be 2 layers of 3/4" marine plywood because of the strength.

    After hurricanes blow through Florida it's nothing to see pine plywood surpass the price of marine plywood. You got alot of homes down there with marine plywood in them.

    The thing about marine plywood is the price is stable. You don't get the wild up and downs. Even if there is going to be a price increase it won't be much and it's announced usually well before it happens. Atleast in boat building circles it is.
    For what you are getting, I don't think marine plywood is overly priced or too high priced.

    American plywood is really an inferior product for boat building. Our plywood is manufactured for housing.