ply for a tender

[halyardmonkey.]

Hiya All,

I want to make myself a ply wood tender as a bit of a project using a stitch and glue method. My question is about ply wood in general. using the plans specify Marine Ply and wondered about the difference between marine and normal builders ply. Also, if you are going to cover the whole thing with epoxy and glass surely the wood is protected any way?

Thanks for any info you can offer

H.M

 

[prv]

Personally I'd not have a problem with using decent WBP for a dinghy. As you say, it's covered in epoxy, and even if it does end up rotting in ten years' time you'll have got a good innings from it. I would use the best marine ply I could find if I was building a bigger boat though (or a cabin top or whatever, since nobody builds ply yachts any more) where you need it to last so your effort's not wasted.

Pete

 

[VicS]

+ 1 for decent exterior ( wbp ) ply. The glue is the same as for marine ply by the spec for the latter restricts voids and surface defects

Sheathing will add to the weight and cost. Epoxy will be expensive compared with polyester but sticks better to wood.

Edges of ply are the vulnerable areas.

The one below was made 35 years ago. Although the photos are few years old now the dinghy is still in fine condition.
I'd have been very disappointed if it had only lasted 10 years. I am hoping it will see me out.

Made from 2 sheets of ply + a few bits of hardwood.

Panels stitched at strategic points with copper wires and laced with nylon monofilament fishing line between. All joints taped with glass tape and polyester resin. It is not sheathed

 

[alahol2]

All of the 4 or 5mm ply in our local 'sheds' seems to have a thick central ply sheathed with very thin outer plies. Is this the normal construction or should there be 3 (or more?) equal plies?

 

[prv]

All of the 4 or 5mm ply in our local 'sheds' seems to have a thick central ply sheathed with very thin outer plies. Is this the normal construction or should there be 3 (or more?) equal plies?

I've seen that stuff too. Barely call it plywood, it's more "some cheap wood, with a veneer each side to make it look better".

Pete

 

[AntarcticPilot]

I am using marine ply (marked BS1088), but I was prepared to use WBP if there had been a significant differential in price. I got mine from http://www.ridgeons.co.uk/wp-content/uploads/2012/07/ridgeonstimberpanel.pdf; the stuff I got is on page 70. The price was very similar to WBP. The company is fairly well-regarded locally, but it's a builder's mercaht more than anything!