Type of wood and suppliers of timber for supports in Australia?

Discussion in 'Materials' started by tontoOx, Feb 25, 2021.

  1. tontoOx
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    tontoOx Junior Member

    I am going to build a folding pram dinghy out of Okoume marine ply and epoxy (glued at least, probably fillets too, and seams likely to be epoxy fibre glassed – undecided about coating approach at the moment though).

    I am aware of encapsulating timbers but I don't know what wood to use for the 25mm x 50mm and 25mm x 25mm (or thereabouts) section support timbers that has good rot characteristics but doesn't have oils in them which will make epoxy difficult to adhere. So that rules out spotted gum, cypress etc. Hoop pine rots like crazy evidently.

    Would appreciate input, also for info on any online suppliers who deliver in Australia by courier (other than Bunnies), thanks.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Boatcraft Pacific specialize in boat timbers and plywood, can't speak to what they are like to deal with, I haven't built much in the way of wooden boats. They are in Queensland. It is strange that Hoop Pine is not regarded as high on the list for durability, yet most local marine plywood is made from it.
     
  3. gonzo
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    gonzo Senior Member

    If you are encapsulating with epoxy, rot resistance is not an issue. Structural characteristics, like bending, and density of the wood are important. Any pine will coat nicely and won't make the boat too heavy.
     
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  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Not all marine ply will be encapsulated, of course, but this Hoop Pine is the standard choice for locally made marine ply, I guess a case of using the best that can be sourced locally. Is Okoume durable ? I guess the prize would be light+ rot resistance, and that no doubt = $$$.
     
  5. Rumars
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    Rumars Senior Member

    Golden cypress (cupressus macrocarpa) or oregon pine would be best.
     
  6. bajansailor
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    bajansailor Marine Surveyor

    I am intrigued by the 'folding' aspect of your dinghy - can you tell us a bit more about it please?
    Is she your own design?
    How are you arranging the 'hinges' re the folding - I assume that they are a sort of waterproof canvas type material?
     
  7. tontoOx
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    tontoOx Junior Member

    Boatcraft Pacific also sell a lot of Hoop Pine regular timber for boatbuilding as well. While a boat is sealed and intact all is well (I guess). The problem is if there is a leak somewhere e.g. in the chines. Okoume (Gaboon) seems to be the gold standard for durable marine ply (I don't know why). Yes, you are right, it is possible to buy marine plywood in Australia made from hoop pine but it is also possible to buy marine plywood made from Okoume and maple as well. Boatcraft Pacific sell marine plywood made from Okoume as well. I recall that on the Boatcraft Pacific they had to send some of the plywood they imported back to the importers.

    I know what I want to use for the marine plywood (Gaboon/Okoume), the quandery I am in is over the solid timber type to use for the supports etc.

    Thank you. I will look into the Oregan pine. I suspect the Cypress would be too oily for the epoxy though.

    I am making it from plans I got on duckworks. It will be a Ken Simpson simple 8' foot pram. It folds in the middle using stainless steel hinges and also uses Tee-nuts and bolts. I don't want to bother with a trailer. The pram will fit in the back of my hatchback and can be used with a trolling motor. It will be used on lakes, rivers etc but not the open sea as such unless close to shore on a calm day. But I won't be using the tape and glue method suggested in the plans. Instead I will use silicon bronze screws, ring tail shank nails, epoxy glue and fibre glass all seams. I saw an 18 footer on YouTube done that way, he pre-drilled pilot holes first, applied epoxy glue (which I assume is just a 1:1 mix of resin and hardener perhaps thickened with flour), put the screws/nails in, then covered the screw/nail heads with epoxy glue, sealed the plywood edges and then fibreglassed all seams. I haven't worked out whether I will coat the boat with marine paint and not bother with coating all the marine ply in epoxy or not. Another note on the hinges. I will drill oversize screw holes, fill the hole with epoxy, then coat a machine screw in thin coat on thread of candle wax or vaseline, put a nut on the end of the machine screw, hang the machine screw in the epoxy by toothpicks under the machine screw head. After the epoxy has set unscrew the machine screws and then screw the hinge in place. Rinse and repeat for other fittings such as cleats etc.
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

    Light weight would appear to be called for, have you considered Paulownia ?
     
  9. tontoOx
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    tontoOx Junior Member

    Thank you! I hadn't heard of Paulownia but that looks very interesting indeed. A google search on it suggested that it is a bit lightweight. Does that mean it can't hold screws I wonder but then again surely not. In the US core sandwich using foam seems to be very popular and fittings go through the FG and core. I will be using epoxy in oversize holes in anycase so that should help there.

    I will see if I can order some Paulownia and do a few tests. Thanks again, greatly appreciated.
     
  10. Rumars
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    Rumars Senior Member

    Your suspicion is wrong. It's a naturalized timber, not a native, and is all you asked for, durable, termite resistant, light, and works well with epoxy.
     
  11. tontoOx
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    tontoOx Junior Member

    Apologies. Various varieties of Cypress are grown in Australia and New Zealand including cupressus macrocarpa. I worked with a cypress (couldn't tell you which variety) and I had trouble painting it because of the resins in it, and it also had a tendency to check (cracks) which is not a desirable trait in a boat. That's why I wondered how it would take to epoxy but it sounds like the cypress you are referring to is different cypress to the one I worked with.
     
  12. bajansailor
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    bajansailor Marine Surveyor

  13. gonzo
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    gonzo Senior Member

    That would not be a good choice. It should get completely encapsulated.
     
  14. tontoOx
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    tontoOx Junior Member

    Apologies. I should have included links and more of an explanation, here goes.

    I am going to build the Simple 8' Pram:
    Simple 8' Pram Plans PDF https://duckworks.com/simple-8-pram-plans/

    I also considered the Fly Fisher:
    Fly Fisher Plans PDF https://duckworks.com/fly-fisher-plans/

    BUT these designs call for using an unusual tape and glue method of construction which involves plasterers tape and Titebond III glue for both adhesion and coating called "Tape and Glue 2". The main issue I have with that approach is to do with repairability and also how waterproof is T3 really? After reading the following assessment and after a lot of Dr Google searching, I came to the conclusion that epoxy is the best solution for both durability and repairability, at least as far as glue and also fiberglassing the seams is concerned.

    Are your glue joints repairable?
    Are Your Glue Joints Repairable? https://www.boatdesign.net/threads/are-your-glue-joints-repairable.8082/

    I also didn't like the idea of using brads mentioned in the plans which can, over time, I have read, either fall out or rust. That's why I will use silicon bronze screws/nails forever embedded.

    I still need to decide what I am going to do to coat the sides and hull. Do I simply coat using varnish and marine enamel paint and recoat every year or two like we used to do to the Enterprise and Firefly during my school days, or do I epoxy fiberglass the inside bottom and outside bottom of the hull and epoxy coat the rest. The latter approach seems to me overkill for a 1/4" hull which has skids for additional reinforcement and would add a lot of weight. Don't know, but I don't have to make that decision until closer to the time.

    I had quite a journey in researching options and how I am going to approach this project. The design I chose may be small and simple, but, it will go on the water so it needs to be safe and durable.

    The most beautiful compact option is a nesting dinghy known as the Eastport nesting pram by Chesapeake where one half sits inside the other half for transportation. You can also fit a sailing rig to it too. The Eastport nesting pram involves more work which wouldn't have put me off, unfortunately it is just a bit too big in its nested state to fit in the back of my car with the rear sits folded down. That's a shame because I did like the design.

    Eastport Nesting Pram https://www.clcboats.com/modules/catalog/boat.php?category_qn=wooden-sailboat-kits&subcat_qn=eastport-pram&code=eastport-nesting-dinghy

    It is possible to get the plans and even a CNC milled kit of parts for the Eastport Nesting Pram dinghy in Australia and they will ship across Australia too:

    Eastport Nesting Pram https://www.denmanmarine.com.au/eastport-nesting-pram-p12/

    Sure, the boat does need to be totally coated/sealed but that does not have to epoxy. Epoxy fiberglassing the internal floor and external floor and coating the rest in epoxy can affect repairability later on if, for example your boat hits a rock. At the moment I have decided to use epoxy for glue, for sealing edges, filling and filets and for for fiberglass tape on all seams. Will I also coat with epoxy too? Don't know, and there is also the toxic aspect of epoxy too.
     

  15. gonzo
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    gonzo Senior Member

    Can you explain how it affects it, particularly as it relates to other coatings? When moisture gets behind the fiberglass/epoxy it will delaminate.
     
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