compound curves in plywood

I would guess that the construction techniques used
were similar to those used in boatbuilding.

http://www.albacore.org/USA/members/...g_albacore.asp
http://www.boats.com/content/default...contentid=1184
http://www.albacore.org/USA/members/...g_albacore.asp
May help.

There is a remarkable wooden flying boat hull in the RAF Museum
at Hendon that was built in the early 1920s. It has a 'moulded'
hull which appears to have been constructed using boatbuilding
techniques of the time.

http://www.rafmuseum.org.uk/supermarine-southampton.htm

With its varnished finish it is simply stunning to
look at.

egroups.com:

I would guess that the construction techniques used
were similar to those used in boatbuilding.

http://www.albacore.org/USA/members/...g_albacore.asp
http://www.boats.com/content/default...contentid=1184
http://www.albacore.org/USA/members/...g_albacore.asp
May help.

There is a remarkable wooden flying boat hull in the RAF Museum
at Hendon that was built in the early 1920s. It has a 'moulded'
hull which appears to have been constructed using boatbuilding
techniques of the time.

http://www.rafmuseum.org.uk/supermarine-southampton.htm

With its varnished finish it is simply stunning to
look at.



All good stuff, but not what I realy need to know. Rummaging around, I
found this, which is a bit enlightening..
http://personal.eunet.fi/pp/gsahv/torture/torture.htm

In article .com,
wrote:

I would guess that the construction techniques used
were similar to those used in boatbuilding.

http://www.albacore.org/USA/members/...g_albacore.asp
http://www.boats.com/content/default...contentid=1184
http://www.albacore.org/USA/members/...g_albacore.asp
May help.

There is a remarkable wooden flying boat hull in the RAF Museum
at Hendon that was built in the early 1920s. It has a 'moulded'
hull which appears to have been constructed using boatbuilding
techniques of the time.

http://www.rafmuseum.org.uk/supermarine-southampton.htm

With its varnished finish it is simply stunning to
look at.

Is everyone forgetting the deHavilland Mosquito? Constructed almost
entirely of cold-moulded plywood.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

"Alan Baker" wrote

Is everyone forgetting the deHavilland Mosquito? Constructed almost
entirely of cold-moulded plywood.

Isn't cold molding done using layers of wood, with glue applied as the wood
is bent in the mold, with the glue setting up in the new shape?
--
Jim in NC

In article ,
"Morgans" wrote:

"Alan Baker" wrote

Is everyone forgetting the deHavilland Mosquito? Constructed almost
entirely of cold-moulded plywood.

Isn't cold molding done using layers of wood, with glue applied as the wood
is bent in the mold, with the glue setting up in the new shape?

Yup. And the original post was talking about just that, ISTM.

"Seems to me even the wettest veneers would split if you
tried to force them into or around a male or female mold. to date,"

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

"Morgans" wrote in message
...

"Alan Baker" wrote

Is everyone forgetting the deHavilland Mosquito? Constructed almost
entirely of cold-moulded plywood.

Isn't cold molding done using layers of wood, with glue applied as the
wood
is bent in the mold, with the glue setting up in the new shape?
--
Jim in NC


Exactly. Plywood is nothing but thin veneers of wood glued together face to
face with the grain running at different angles, generally ninety degrees,
but sometimes other angles for special applications. Plywood is normally
laminated on a flat plate making a flat sheet of wood that is very hard to
bend into anything other than a conical curve because the laminated layers
are glued together so they can't slide.

Cold Moulding is merely a low temperature process using ordinary waterproof
glues, for makeing you own plywood from thin veneers that is formed over
something other than a flat plate, so that it comes out with the shape of
the mould it was laminated in or on, as the case may be.

No reason in the world you can't make compound curved plywood by laminating
it up over a male plug and useing a vacuum bagging process to apply the
requisite clamping pressure. Ideally pick a good waterproof glue that gives
you a rather long working time and bonds well with a fairly low clamping
pressure. Say 5 to 10 pounds per square inch clamping pressure that you can
easily obtain with simple vacuum equipment. Working time of fifteen or
twenty minutes should allow time to build up thin laminations and get
clamping pressure onto them. This can be stretched a lot by using staples
with a pull pad under them to apply temporary clamping pressure as you build
up the lamination.

I have only done this using older glues like resorcinol and aerolite and
urea resin. I would think it would work very well with some of the more
modern epoxy based wood glues like T-88, etc. If it works for canoes, it
oughtta work for a Bowlus. :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )