On Thu, 17 Feb 2005 15:17:50 -0600, Dave Allyn
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

I am building a S&G canoe. I am going to use fiberglass cloth on the
entire outside for extra strength, and to prevent any checking in the
plywood. I'm useing 1/4" BCx plywood.

What weight of cloth would I want to use for this aplication? And the
next question, how would I decide that on future projects? Is there a
general rule of thumb for weight?

A _rough_ rule of thumb is that if you use full thickness of ply as
designed, and only want this to stop checking and help keep the wood
dry, then use a really light cloth, but reinforce all corners, as
that's where most abrasion is. Also two layers on the bottom. If you
use thinner ply, then build up with cloth until the boat weighs the
same as it would have in ply (reasonably well-laid glass cloth will
take up its own weight in resin, roughly), and you will probably have
a stronger boat.

Otherwise, talk to the canoe's designer. Always a good idea.


One last question, I know I need to tape the inside and outside with
fiberglass tape on the seams, but If I cover the whole outside with
cloth, do I still need the tape on the outside of the seams?

Unless you can cover the whole boat with cloth before you move it from
the building jig, then yes. It's literally what holds the whole boat
together.