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plywood choices

Discussion in 'Serious Boat Building Questions' started by 1fast68, Sep 9, 2008.

  1. 1fast68

    1fast68 Member

    I am finishing up my second boat. This one I built a little smaller with different needs. I have a question as I am starting to think about my 3rd boat. I had to build this boat out of 1/4" Birch. It was the best wood I could find that was thin. It ended up being 3/16" and weighed 23lbs a sheet. I only have well known department lumber stores close and can't find 1/8" plywood but like the look of Birch. Is the 1/8" Luan or Okame (sp) that much lighter than the Birch I used?
  2. oldsparkey

    oldsparkey Well-Known Member

    I just made the Sasquatch 14 x 30 from the kit Matt offers and the 3mm wood for the boat ( three sheets) when all the panels were together the whole boat weighed 17 pounds. When all the rest , epoxy , fiberglass , rails , spacers , seat and the rest was added the completed boat weighs 30 pounds.

    I made a Uncle John Pirogue from 1/4 inch wood (two sheets) and it weighed 50 pounds when done , made another from 1/8th inch wood , it weighs 32 pounds .... both boats are identical except for the wood they are made from.

    I will not get into the inexpensive wood over the expensive wood , that is the builders choice but yes, the thinner wood does make a lighter boat.

  3. Jimmy W

    Jimmy W Well-Known Member

  4. Lee Schneidermann

    Lee Schneidermann Well-Known Member

    I completed a Freedom 15-4 build from JEM and used 1/4" birch ply from the local box store. While I "cheated" a bit on the deck, the final wieght was 46 1/2 #.
    That's a "first build" and it probably has at least 1/2 gallon too much epoxy, and full 6oz. cloth sheathing her.
    In short, it's too heavy for my taste.
    Don't get me wrong, it's a fine boat and it looks great, paddles great, and performs great. I was just hoping to be a little more "professional" with my build.
    My next attempt will be an even longer version of my first, and I'm betting it will wiegh less than the first when complete.
    The reason? Experience. We all learn volumes from our first builds. I know so much more now than I did even half way through my first build, it's almost a miracale that I finished the first boat.
    If all you can find is 1/4" ply from a box store, use it. But if you can get to the "old" name suppliers and ask them to drum up thier supplier cataloge, chances are they'll find you some suitable 3mm to make your next boat.

  5. JEM

    JEM Well-Known Member

    Ok I think I have a solution.

    The main problem with getting marine plywood if not available locally is the shipping cost. Mailing 4 x 8 sheets is expensive.

    However, mailing 2 x 8 sheets isn't that bad. I'm working with a CNC kit vendor who is willing to see and ship plywood in 2 x 8 sheets.

    So a person could take a set of plans, draw out the panels on some cheap ply, then use them as patterns on the 2 x 8 sheets. I'll even try to adjust the nesting of the panels so a builder wouldn't have to buy extra.

    I'm working out the details but if anyone is interested, I can work up a quote on shipping Okoume as 2 x 8 sheets.
  6. 1fast68

    1fast68 Member

    I really jealus now. I don't even have the cleats on yet or the glass and I'm weighing 107lbs. Granted this is a 12' x 48" Jon boat. I could have saved 48lbs using 1/8" Okome.
  7. JEM

    JEM Well-Known Member

    might have been a weeeeee bit thin. :p
  8. seedtick

    seedtick Well-Known Member

    I hesitate to jump in on this 'cause I don't really worry that much about the weight of the final boat..............but,

    Based on JimmyW's post that 3/16"plywood weighs 16 pounds then 1/8" should weigh about 10lb and 1/4" should weigh about 20lb.

    A 12' pirogue, e.g. has less than two sheets of plywood in it so the weight contributed by the plywood would be less than 20 lb difference

    You can build a pretty stout pirogue out of 1/4" and not have to use epoxy and glass. However 1/8" would require epoxy and glass or polyester and glass and probably additional bracing i.e. ribs.

    Anyway my question is "what is the difference in weight of a 1/4" pirogue with no epoxy/glass vs the same boat in 1/8" with epoxy/glass?"

    I reckon in the end there isn't that much difference in weight and you could save yourself a whole bunch of epoxying and sanding and exposure to harsh chemicals by just building a wood boat.
  9. tx river rat

    tx river rat Well-Known Member

    We are on the same wave link on this. I have built out of 1/8 3/16 and 1/4 In my feeble little mind 3/16 is the best size for me lighter than the quarter easier to bend ,stiffer than the 1/8 and much easier to work with
    weight wise between the 1/8 and 3/16 is nearlly the same because less glass and resin is used.
  10. JEM

    JEM Well-Known Member

    I found a place that sells 2mm okoume. Who wants a kit from it? :twisted: :p
  11. Lee Schneidermann

    Lee Schneidermann Well-Known Member

    I'd consider it if you could show me a supplier with 10oz fiberglass that will clear out when wetted!! :wink: :wink:

  12. 1fast68

    1fast68 Member

    Off this subject, but....can a boat be made water proof without epoxy or varnish. I would like to make a functional antiqe looking boat and have the grain of the wood be the finish and feel. Or at least a flat sheen varnish?
  13. oldsparkey

    oldsparkey Well-Known Member

    YOU HAVE 2mm wood available :D :D :D

    My dreams have been answered , there is a wood boat building God , the force is smiling on me , Hot Dam !!!!!!! Jumping up and down , spinning in circles , dancing on the top of the computer , Life does not get any better then this. :D Unless it is a cold , frosty , iced , Budweiser. :lol: 2mm wood ... Hot Dam we will be rocking and looking for a wood boat (paddling an camping kind) under 30 pounds.

    Matt ... Ya got this old boy a thinking ........ Give me some time , I'm a slow thinker about which boat to do it with. :roll:

    You need some form of water protection or repellent and the varnish would be it ... Best to check with Keith , seedtick since they make to old fashion boats and Matt might offer an idea also.
    Only other choice would be paint and then no one would see the wood........

  14. hairymick

    hairymick Well-Known Member


    Boats were being built from wood for centuries before the advent of epoxy/poly resin.

    It is still doable today but one need to ask the question "is it worth it?"

    In a purely practical sense, I don't think that it is.

    Epoxy resin mixed with wood flour is a superior bonding agent (glue) to any other that I know of. As it is a superior timber protectant. It is easier to use to build a very good boat that it is to learn the miriad of skills required to even contemplate building building a more "traditional" boat using the old methods. Most of these skills are now lost, or at best, retained by a very few highly talented wood worker masters/shipwrights. AKA Seedtick.

    Good luck with your build, what ever method you finally decide to run with mate.
  15. 1fast68

    1fast68 Member

    I knew it wouln't be to pratical to use, but as long as it could keep the butt dry would be the biggest concern. Is seedtick on the forum much?
  16. oldsparkey

    oldsparkey Well-Known Member

    Only when we put a sandspure in his blanket and he an Keith are not dodging Hurricanes. :lol: :lol: :lol:

    PS.. Member 279 .page six.
  17. Jimmy W

    Jimmy W Well-Known Member

  18. Kayak Jack

    Kayak Jack Well-Known Member

    Weighing in late here. 1fast68, Matt would be a good one to ask on this, but a thinner wood will work better with narrower panels, say no more than 4" wide. A flat bottomed boat normally has large, wide panels, and needs to be either thicker wood, or have some bracing for stiffening function.

    Stiffeners could be longitudinal strips running lengthwise for part of the length of the boat, on panels that seem to oilcan in use. Sometimes, it's wise to build the boat, try it out, and then see where stiffening seems needed, rather than just glue it on without field information at hand.

    It's possible to mix thicknesses in a boat hull, but more difficult if it's a semi-rounded hull rather than a flat bottom.

    Again, were I you, I'd be asking Matt for guidance.
  19. JEM

    JEM Well-Known Member

    Jack is correct. Hulls with multi panels that are narrower in width work better with thinner ply due to the angles between the panels acting as braces.
  20. seedtick

    seedtick Well-Known Member

    neither friend Keith nor I have built a pirogue that was skinned in glass and epoxy

    While I appreciate the comment from Mick, I view myself as more meticulous than highly talented. Building boats can be addictive as most folks here have built more than one. The key is to learn from each build and each one will improve. The not so secret to a dry boat is for it not to leak. Making better cuts and fitting panels together make for better seams. Better seams make for no leaks. If you're building boat number three and the seams don't fit tighter than boat number one, then you haven't learned much.

    No wanting to throw cold water on anyone's building techniques, but I think it's way easier to fit the parts so they're water tight than to fill in gaps with wood flour and epoxy and cover with cloth to stop leaks.

    We use epoxy for glue almost exclusively. Think it's stronger and more waterproof than the Weldwood resin that has been used for years. On the other hand, I've got my Father's old bateau (weldwood glue, marine plywood, brass screws) that's over 50 years old and it doesn't leak. Don't know how long epoxy will last.

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