The plywood monocoque car guy

On Fri, 18 Apr 2008 22:18:56 -0700, "Rich S."
wrote:

"Morgans" wrote in message
...
snip
For those looking for unusual plywood, I suggest you do some looking in
your local yellow pages (hopefully in a relatively large population area)
under plywood, and see if you can find a place that advertises a specialty
of stocking unusual types and grades of plywood. There are more plywood
types under the sun, than you can imagine, and I can imagine a LOT ! g

Jim ..........

The place in Tacoma where I bought most of the Finnish Birch plywood for the
Emeraude also stocks molded plywood. This is intended for use in rolling
over cardboard with knives imbedded in the wood. The cardboard is cut into
the various shapes, such as for folding into boxes or packing. The plywood
half-cylinders are about 3/4" thick and are not bendable - they're
structural. Real pretty stuff, too with birch outer layers.

They advertise in Sport Aviation. Beside almost all thicknesses of Finnish
Birch for aviation (.5 mm, 1.0 mm, 1.5, 2.0, 2.5, 3.0, etc.) they sell
Italian Poplar bending plywood. Ideal for making single curve windshield
molds, for instance. I was lucky to have a supplier like this only a
half-hour drive away. When you add in the fact that the principal wholesaler
of aircraft spruce in the nation is also in Tacoma, this is an ideal place
to build a wooden airplane, boat, or organ.

Rich S.

Isn't aircraft ply made with the plies on a 45 degree bias for
bending?
** Posted from http://www.teranews.com **

In article ,
clare at snyder dot ontario dot canada wrote:

On Fri, 18 Apr 2008 22:18:56 -0700, "Rich S."
wrote:

"Morgans" wrote in message
...
snip
For those looking for unusual plywood, I suggest you do some looking in
your local yellow pages (hopefully in a relatively large population area)
under plywood, and see if you can find a place that advertises a specialty
of stocking unusual types and grades of plywood. There are more plywood
types under the sun, than you can imagine, and I can imagine a LOT ! g

Jim ..........

The place in Tacoma where I bought most of the Finnish Birch plywood for the
Emeraude also stocks molded plywood. This is intended for use in rolling
over cardboard with knives imbedded in the wood. The cardboard is cut into
the various shapes, such as for folding into boxes or packing. The plywood
half-cylinders are about 3/4" thick and are not bendable - they're
structural. Real pretty stuff, too with birch outer layers.

They advertise in Sport Aviation. Beside almost all thicknesses of Finnish
Birch for aviation (.5 mm, 1.0 mm, 1.5, 2.0, 2.5, 3.0, etc.) they sell
Italian Poplar bending plywood. Ideal for making single curve windshield
molds, for instance. I was lucky to have a supplier like this only a
half-hour drive away. When you add in the fact that the principal wholesaler
of aircraft spruce in the nation is also in Tacoma, this is an ideal place
to build a wooden airplane, boat, or organ.

Rich S.

Isn't aircraft ply made with the plies on a 45 degree bias for
bending?
** Posted from http://www.teranews.com **

Some is 45; others are 90 -- you can specify when ordering.

--
Remove _'s from email address to talk to me.

On Apr 19, 8:26 pm, Orval Fairbairn
wrote:

Isn't aircraft ply made with the plies on a 45 degree bias for
bending?
** Posted fromhttp://www.teranews.com**

Some is 45; others are 90 -- you can specify when ordering.

I think it's the face plies that are either 90 or 45 to the cut
edges, and the core plies are at 90 degrees to the face plies. I
haven't seen plywood with the cores at 45 to the faces.
45 degree faces are for places where the design calls for
angled grain across some structure (like a box spar) to closely align
with the stress forces, while avoiding so much waste.

Baltic birch (or Finnish birch, if you prefer) will bend most
readily across the face grain (grain 90 degrees to the bend line) if
it's dampened. I used to spray water on the faces and run a hot
clothes iron across it, turning that water to steam and driving it in.
Doesn't hurt the resorcinol ply glue. I once cut a 3/4" wide strip of
1.5mm ply, face grain running the long way, steamed it, and wrapped it
around a pencil spiral-fashion without it buckling or breaking. Tied
it that way and when it was dry it pretty much held that shape.
Trying to bend it with the grain (grain parallel to the bend
line) will usually fracture the core plies, since it's pretty hard to
get moisture that deep.

Dan

On Apr 19, 8:05 pm, wrote:
Trying to bend it with the grain (grain parallel to the bend
line) will usually fracture the core plies, since it's pretty hard to
get moisture that deep.
-------------------------------------------------------------------------------------------

Try adding two ounces of household ammonia and ONE DROP of liquid
detergent (or a drop of Kodak 'Photo Flow') to each GALLON of water.
Soak over-night then heat the soaked wood to 165 to 185F degrees.
Bend to the desired shape and allow to dry. For extremely deep
curves, do the bend in graduated stages, keeping the plywood moist
until the desired shape has been achieved.

Thinner is better; make the part as two shells if needed to achieve
the desired thickness.

This procedure does not work with all plywoods.

-R.S.Hoover

wrote:
On Apr 19, 8:05 pm, wrote:

Trying to bend it with the grain (grain parallel to the bend
line) will usually fracture the core plies, since it's pretty hard to
get moisture that deep.
-------------------------------------------------------------------------------------------


Try adding two ounces of household ammonia and ONE DROP of liquid
detergent (or a drop of Kodak 'Photo Flow') to each GALLON of water.
Soak over-night then heat the soaked wood to 165 to 185F degrees.
Bend to the desired shape and allow to dry. For extremely deep
curves, do the bend in graduated stages, keeping the plywood moist
until the desired shape has been achieved.

Thinner is better; make the part as two shells if needed to achieve
the desired thickness.

This procedure does not work with all plywoods.

-R.S.Hoover



And - do the ammonia test as a test.

Because the wood may stay quite rubbery afterwards...