What is involved in attaching a sheet of teak veneer to a plywood board.
Can one simply glue and weigh down the veneer, or are clamps necessary
to
achieve a good bond? The application here is actually refinishing the
teak benches in the outside cockpit of a sailboat. The top layer of
teak
from the original teak plywood benches has detached and broken up. I
would rather not remove the benches to do the job, hence my requests
about
doing the job, in place. Any recommendations for a good marine type
glue
to do the attachment?
On Thu, 15 Jan 2004 05:46:08 GMT, Sherwin Dubren
<[email protected]> wrote:
>What is involved in attaching a sheet of teak veneer to a plywood board.
Applying adequate pressure over the whole area of the bond, for a
period appropriate for the adhesive being used.
I like to use hot hide glue for veneering, because it allows me to use
"hammer veneering". I apply the veneer and press it down by working it
with a squegee-like "hammer". As hot hide glue has very high tack as
soon as it cools, this traditional process gives a good result from
very short working or clamping times. I'd not good for long-term water
resistance though.
For other adhesives; waterproof boat-building resorcinols, everyday
PVAs, or even instant-use tube hide glue, then you need to clamp it.
The ease of doing this depends on the shape - a flat board is easier
than a curve.
For flat boards, and for some simple curves, then you can use a
clamped "caul". This is a sheet of plywood, MDF or even heavy fabric
which is clamped down or pulled tight. A flat board needs to be stiff
enough not to raise a bubble, a convex curve needs a flexible caul
with adequate tension (sewing a sleeve on one edge, insertign a
wooden batten and pulling it tight with clamps can be workable.
For complex shapes, use a vacuum bag. Vac bagging is pretty easy, but
you need a vacuum pump. You also need a vacuum pump that is happy to
run for some hours, pumping out a closed bag. "Blower" pumps and
vacuum cleaners won't do this. A fridge compressor may overheat or
arc. Best thing is a lab rotary pump, easily found S/H via eBay. You
only need a minimal vacuum - just a few psi below atmospheric.
The bag itself is made from heavy polyethylene and duct tape. It's
really pretty easy to make your own. Clever bits like fabric
reinforcement, elastic panels for compound curves, or quick-loading
zipper fasteners are nice, if you happen to need them.
If you're vacuum bagging, then check the strength of your buck
beforehand. There's a lot of force involved with a vacuum bag and the
time to find that your buck collapses under load isn't when you've got
a fresh glue-up in there !
>Any recommendations for a good marine type glue
>to do the attachment?
Whatever you use for general woodworking on a boat. Powdered phenolic
or resorcinol resins like Cascophen (or your local brands) ought to do
it.
I'd expect you could make a 3/4" plywood caul to clamp this veneer
down. Make two, make them oversize, and drill a lot of bolt holes
around the edge. You can clamp them up with coach bolts and wing nuts,
at about 4" spacing. Then you turn it over to do the mirror-image
side.
--
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