plywood, 1088 vs 6566 for marine use

[frameshop]

can anyone give us a realistic picture of these two standards and how they come into play in the encapsulated plyWOOD boatbuilding process????????

[Tom Lathrop]

There is no doubt that the BS1066 standard is superior to to the 6566 standard. I don't have the particulars of these standards but have used quite a bit of both.

Sometimes it may be difficult to distinguish the difference of two sheets of the two types side-by-side. Either type can be used in boatbuilding but the 6566 will take more care in inspection for faults such as poor surfaces, voids in the inner plys, delamination of plys and quality of wood in inner plys.

Given these problems, it may be safer to pay the extra bucks for the better grade, especially if you are not able to make the judgements necessary to insure that poor material is not used.

Both types are made from the same basic wood and use waterproof glue in their construction.

For construction that will not be visible and will be sheathed with fabric/epoxy, marine fir may be a better choice if money is the determining factor. Fir is more durable and stronger than occoume but a bit heavier.

Very good boats have been built from any of these plywoods. Main thing is to NEVER EVER use non waterproof glued plywood. Forget the advice given by some that incapsulating with epoxy will make bad wood good.



[This message has been edited by Tom Lathrop (edited 10-10-2001).]

[Don Maurer]

The main difference is that BS1088 has plys of very near the same thickness (usually 1 - 1.5 mm). BS6566 has much thinner outer faces. What this means to boatbuilders is that if you need to bend the plywood in the long direction, BS6566 will have less strength and begin to splinter at a greater radius than BS1088. Also, if you need to do any sanding, you are likely to sand right through the outer veneers on BS6566 unless you are very careful. Coating the surfaces with epoxy has very little effect on strength, unless fiberglass, dynel, or other structural fabric sheathing is also used.