Which plywood for the plyak

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gbgb
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Which plywood for the plyak

Post by gbgb »

Many years ago (20+) I built the CV16. At that time good quality marine plywood was available in Israel, as there were two manufacturers which manufactured for export.
Since then they both shut down, imported marine plywood supply is very limited and is mainly on the thicker side (10mm and up).
I plan on building the Plyak and began thinking of the options:
1. Birch - strong and waterproof glue, however heavier than mahogany by 25-30%. It can be acquired at 4mm so it will weigh almost like the 6mm version. Question is will sheathing on the outside only be enough for this thickness (if I understand correctly the 6mm version is FG sheathed outside only and the 3-4mm version is sheathed inside as well)
2. Poplar - can get it at 4mm (maybe even 3). light. waterproof glue? Not sure, but maybe the epoxy protection is enough. But is it strong enough?
3. Cheap interior plywood. The faces are Okume. inside layers - no clue. Glue is probably not waterproof.

I guess my main concern here is weight vs. strength as the boat will never be in the water more then several hours at a time.

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cape man
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Re: Which plywood for the plyak

Post by cape man »

I'd go for the 4mm birch and glass inside and out with 4oz cloth.
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OrangeQuest
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Re: Which plywood for the plyak

Post by OrangeQuest »

Welcome to the forum gbgb!

I have used a lot of birch plywood over the years to build radio controlled boats and it holds up to the high moisture environment of boating/modeling with very little waterproofing. Because the stuff I get is thin multi-plies it is easy to flex, sand, cut and fairly strong. Never heard or used the over drill, fill and then tap hole for holding screws. A few of the planning hulls I built would take on water and the wood on the inside was not sealed but they were not built to last generations either. :)

Here is an article on the different woods you mentioned. Birch seems to be the best choice.

https://www.dummies.com/crafts/types-of ... odworking/
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
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gbgb
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Re: Which plywood for the plyak

Post by gbgb »

Thanks for the replies.
I am in luck - found a vendor that holds 4mm Okume marine plywood from Italy.
Does not have 6mm. I assume this is required only for the frames. So for this I will use birch (They have 8mm, but then the weight will be the same as 6mm birch - better stick to the plans recommended thickness).

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OrangeQuest
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Re: Which plywood for the plyak

Post by OrangeQuest »

That is good news!! When you start the build you could start a thread and post lots of pictures!! Good luck and happy building!
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
A. A. Milne

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Re: Which plywood for the plyak

Post by Fuzz »

Yes please start a build thread! We have builders from all over the world but you would be the first from your country as far as I know.

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