I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

TIA.

Dick Snyder

Dick Snyder wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

You should get some bending plywood which has all the plys running in
the same direction allowing it to bend easily,

In article , "Dick Snyder" wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

Use bending plywood, and cover it with birch veneer.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Dick Snyder wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

TIA.

Dick Snyder

What about kerfing the interior sides of the 1/4" plywood? The center
piece could be kerfed on one or both sides.

I tried cutting the interior side of one of the pieces of plywood with a
utility knife. When I tried to bend the plywood it just cracked at one of
the cuts. Maybe I will kerf it to see if that works any better.
"RayV" wrote in message
ups.com...

Dick Snyder wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one
side
as both the top and bottom with be visible so I decided to laminate 3
pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but
I
need to conquer this splitting problem. I would appreciate any help you
can
offer.

TIA.

Dick Snyder

What about kerfing the interior sides of the 1/4" plywood? The center
piece could be kerfed on one or both sides.

"Dick Snyder" wrote in message
. ..
I tried cutting the interior side of one of the pieces of plywood with a
utility knife. When I tried to bend the plywood it just cracked at one of
the cuts. Maybe I will kerf it to see if that works any better.

May be kind of dumb, but what about wetting it? Like sheetrock for an arch.

On Wed, 25 Oct 2006 09:26:46 -0400, Dick Snyder wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one
side as both the top and bottom with be visible so I decided to laminate 3
pieces of 1/4" plywood. I plan to use polyurethane glue to do the
lamination but I need to conquer this splitting problem. I would appreciate
any help you can offer.

Watch the grain direction of the top sheet. You want to orient the grain so
it is perpendicular to the direction of the bend.

Also, try bending plywood for at least the middle of the three layers. You may
not like it for exposed surfaces. Doug suggested using three layers of this,
and veneer for the exposed surfaces, which IMO is the way to go if you have a
way to apply the veneer.

--
Art Greenberg
artg at eclipse dot net

I can't totally wet it as I have to apply polyurethane glue to some of the
surfaces.
"Tim Taylor" wrote in message
m...

"Dick Snyder" wrote in message
. ..
I tried cutting the interior side of one of the pieces of plywood with a
utility knife. When I tried to bend the plywood it just cracked at one of
the cuts. Maybe I will kerf it to see if that works any better.

May be kind of dumb, but what about wetting it? Like sheetrock for an
arch.

"Dick Snyder" wrote in
:

I can't totally wet it as I have to apply polyurethane glue to some of
the surfaces.

So, why do you _need_ to use the poly glue?

Patriarch

Maybe I don't _need_ to do it but I have been advised by others to use it to
minimize the tendency of the wood to lose some of the bend so I am going in
that direction unless I hear some reason to go another way.
"Patriarch" wrote in message
. 136...
"Dick Snyder" wrote in
:

I can't totally wet it as I have to apply polyurethane glue to some of
the surfaces.

So, why do you _need_ to use the poly glue?

Patriarch

Dick Snyder wrote:
I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate
3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the
lamination but I
need to conquer this splitting problem.

Bending plywood and epoxy.

Poly isn't going to cut it.

Lew

Get some plywood that can do that:

http://www.vandykes.com/product/02007822/
or
http://www.bd-international.com/
or
http://www.boulterplywood.com/FlexiblePlywood_4.htm

Dick Snyder wrote:

I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

TIA.

Dick Snyder

Dick,
I'm with Lew about the Epoxy. If not that, I'd go with Titebond II or III
before the poly.

Steam, soak, or 'local hot towel' if you want to use the stuff you already
have.

Cut your pieces 'over length' by a good bit. Re-make the form with a tighter
curve then the finished lamination {to allow for 'springback'}. Soak the
pieces - in the bathtub if necessary. {If still not long enough . . . lay
out a piece of plastic, put hot-water soaked bath towels on it, lay the
strips of ply on the towels and roll them up, wrapping the plastic around
all.}

Take out the ply strips, and clamp to form, piece by piece. Either 'square'
at one end and let the other 'stairstep', or let both ends 'stairstep'. DO
NOT glue and use LOTS of clamps. Let completely dry . . . I'd go at least a
week.

When dry, unclamp, apply glue, and re-clamp. After another week, unclamp,
sand sides, and trim to square off ends. Do whatever edge treatment you want
and trim to final size just before assembly.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

"Dick Snyder" wrote in message
...
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one
side
as both the top and bottom with be visible so I decided to laminate 3
pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but
I
need to conquer this splitting problem. I would appreciate any help you
can
offer.

TIA.

Dick Snyder

The problem I think will be that the book case has to be stained to match
other furniture in the room that is birch. I'm worried that if I buy bending
plywood, it will not match. Thoughts?


"Pat Barber" wrote in message
...
Get some plywood that can do that:

http://www.vandykes.com/product/02007822/
or
http://www.bd-international.com/
or
http://www.boulterplywood.com/FlexiblePlywood_4.htm

Dick Snyder wrote:

I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the 1/4" plywood splitting. I can not use 3/4" plywood and make cuts in
one side as both the top and bottom with be visible so I decided to
laminate 3 pieces of 1/4" plywood. I plan to use polyurethane glue to do
the lamination but I need to conquer this splitting problem. I would
appreciate any help you can offer.

TIA.

Dick Snyder

Hi Ron,

This seems like it can work. Any particular Epoxy you would recommend? I can
get the pieces in a bathtub. I will do as you suggest.

Thanks.

Dick


"Ron Magen" wrote in message
news:EsO%g.4179$PA3.3426@trndny04...
Dick,
I'm with Lew about the Epoxy. If not that, I'd go with Titebond II or III
before the poly.

Steam, soak, or 'local hot towel' if you want to use the stuff you already
have.

Cut your pieces 'over length' by a good bit. Re-make the form with a
tighter
curve then the finished lamination {to allow for 'springback'}. Soak the
pieces - in the bathtub if necessary. {If still not long enough . . . lay
out a piece of plastic, put hot-water soaked bath towels on it, lay the
strips of ply on the towels and roll them up, wrapping the plastic around
all.}

Take out the ply strips, and clamp to form, piece by piece. Either
'square'
at one end and let the other 'stairstep', or let both ends 'stairstep'. DO
NOT glue and use LOTS of clamps. Let completely dry . . . I'd go at least
a
week.

When dry, unclamp, apply glue, and re-clamp. After another week, unclamp,
sand sides, and trim to square off ends. Do whatever edge treatment you
want
and trim to final size just before assembly.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

"Dick Snyder" wrote in message
...
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one
side
as both the top and bottom with be visible so I decided to laminate 3
pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but
I
need to conquer this splitting problem. I would appreciate any help you
can
offer.

TIA.

Dick Snyder

I didn't read carefully enough before replying a few minutes ago. I see that
Boulterplywood has a flexible birch!

"Pat Barber" wrote in message
...
Get some plywood that can do that:

http://www.vandykes.com/product/02007822/
or
http://www.bd-international.com/
or
http://www.boulterplywood.com/FlexiblePlywood_4.htm

Dick Snyder wrote:

I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the 1/4" plywood splitting. I can not use 3/4" plywood and make cuts in
one side as both the top and bottom with be visible so I decided to
laminate 3 pieces of 1/4" plywood. I plan to use polyurethane glue to do
the lamination but I need to conquer this splitting problem. I would
appreciate any help you can offer.

TIA.

Dick Snyder

In article ,
Dick Snyder wrote:
I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with the
1/4" plywood splitting. I can not use 3/4" plywood and make cuts in one side
as both the top and bottom with be visible so I decided to laminate 3 pieces
of 1/4" plywood. I plan to use polyurethane glue to do the lamination but I
need to conquer this splitting problem. I would appreciate any help you can
offer.

TIA.

Dick Snyder



How are the splits happpening? Is the plywwod actually cracking or is
it delamination? Splitting is a little vague here.

What is the radius of the curve? Perhaps instead of 3 piesces of 1/4"
you could try 6 pieces of 1/8" Baltic birch.

--
No dumb questions, just dumb answers.

Larry Wasserman - Baltimore, Maryland -

"Dick Snyder" wrote in message
. ..
Hi Ron,

This seems like it can work. Any particular Epoxy you would recommend? I
can get the pieces in a bathtub. I will do as you suggest.

Thanks.

Dick

I'd follow Ron's advice. I had a question or two on my first bent lamination
and his thoughts were right on. As for the wetting I suggested, I know what
a piece of ply left out accidentally in the rain looks like!

The wood was splitting in a line parallel to the grain. I am bending with
the grain and it was splitting along the grain and not at the lamination. I
have gotten lots of great advice from this group (as usual!) and I am going
to get some bending birch (it is made using a radial cut so it has a natural
bend to it) from Boulter Plywood here in Boston and I am going to use epoxy
to do the lamination rather than the polyurethane glue I had planned on
using.


How are the splits happpening? Is the plywwod actually cracking or is
it delamination? Splitting is a little vague here.

What is the radius of the curve? Perhaps instead of 3 piesces of 1/4"
you could try 6 pieces of 1/8" Baltic birch.

--
No dumb questions, just dumb answers.

Larry Wasserman - Baltimore, Maryland -

Another way to do this is to buy the flexible mdf
and cover that with birch veneer.

That, of course will require a veneering vacum
bag and pump.....

I would stick with the flexible birch from Boulter.

Glad I could help you...

Dick Snyder wrote:

I didn't read carefully enough before replying a few minutes ago. I see that
Boulterplywood has a flexible birch!

"Pat Barber" wrote in message
...

Get some plywood that can do that:

http://www.vandykes.com/product/02007822/
or
http://www.bd-international.com/
or
http://www.boulterplywood.com/FlexiblePlywood_4.htm

Dick Snyder wrote:


I'm making a book case for my daughter and she wants a curved top. I have
made a form over which to do the bending but I am having a problem with
the 1/4" plywood splitting. I can not use 3/4" plywood and make cuts in
one side as both the top and bottom with be visible so I decided to
laminate 3 pieces of 1/4" plywood. I plan to use polyurethane glue to do
the lamination but I need to conquer this splitting problem. I would
appreciate any help you can offer.

TIA.

Dick Snyder

Dick Snyder wrote:
I tried cutting the interior side of one of the pieces of plywood with a
utility knife. When I tried to bend the plywood it just cracked at one of
the cuts. Maybe I will kerf it to see if that works any better.

It should work bettter as a kerf removes material so that there
is less tension on the convex side.

--

FF

Still cracked. I am going to go with bending birch plywood and epoxy.

wrote in message
oups.com...

Dick Snyder wrote:
I tried cutting the interior side of one of the pieces of plywood with a
utility knife. When I tried to bend the plywood it just cracked at one of
the cuts. Maybe I will kerf it to see if that works any better.

It should work bettter as a kerf removes material so that there
is less tension on the convex side.

--

FF

I visited Boulter today to buy bending birch as they are near the daughter
for whom I am making the book case. I note that the bend puts the finish
side on the inside of the curve. I need to have a finish side on both sides
of the curved top of the bookcase. Can I bend the bending birch the other
way without it cracking? I can of course just try it out but I'd like to get
some advance knowledge before I waste some material.

TIA.

Dick Snyder
"Pat Barber" wrote in message
...
Another way to do this is to buy the flexible mdf
and cover that with birch veneer.

That, of course will require a veneering vacum
bag and pump.....

I would stick with the flexible birch from Boulter.

Glad I could help you...

Dick Snyder wrote:

I didn't read carefully enough before replying a few minutes ago. I see
that Boulterplywood has a flexible birch!

"Pat Barber" wrote in message
...

Get some plywood that can do that:

http://www.vandykes.com/product/02007822/
or
http://www.bd-international.com/
or
http://www.boulterplywood.com/FlexiblePlywood_4.htm

Dick Snyder wrote:


I'm making a book case for my daughter and she wants a curved top. I
have made a form over which to do the bending but I am having a problem
with the 1/4" plywood splitting. I can not use 3/4" plywood and make
cuts in one side as both the top and bottom with be visible so I decided
to laminate 3 pieces of 1/4" plywood. I plan to use polyurethane glue to
do the lamination but I need to conquer this splitting problem. I would
appreciate any help you can offer.

TIA.

Dick Snyder

Dick Snyder wrote:
I didn't read carefully enough before replying a few minutes ago. I see that
Boulterplywood has a flexible birch!


Or do as Mr Miller suggested and cover it with Birch veneer.
Probably the birch bending plywood is cheaper, but keep
the veneer in mind in case the grain is not to your liking.

--

FF

On Wed, 25 Oct 2006 13:29:43 -0400, "Dick Snyder"
wrote:

I can't totally wet it as I have to apply polyurethane glue to some of the
surfaces.

You can't???!?!?!

Read the directions on the polyurethane glue.

Might be an eye-opener.

I just re-read the directions on the glue. I am using Gorilla Glue by the
way. It says dampen one wood surface and apply the glue to the second
surface. The moisture activates the glue.


"Prometheus" wrote in message
...
On Wed, 25 Oct 2006 13:29:43 -0400, "Dick Snyder"
wrote:

I can't totally wet it as I have to apply polyurethane glue to some of the
surfaces.

You can't???!?!?!

Read the directions on the polyurethane glue.

Might be an eye-opener.

Dick Snyder wrote:
I visited Boulter today to buy bending birch as they are near the daughter
for whom I am making the book case. I note that the bend puts the finish
side on the inside of the curve. I need to have a finish side on both sides
of the curved top of the bookcase. Can I bend the bending birch the other
way without it cracking? I can of course just try it out but I'd like to get
some advance knowledge before I waste some material.

TIA.

Dick Snyder
"Pat Barber" wrote in message
...
Another way to do this is to buy the flexible mdf
and cover that with birch veneer.

That, of course will require a veneering vacum
bag and pump.....

Nope.


I would stick with the flexible birch from Boulter.



Or again you could take Mr Miller's suggestion
and use Birch veneer. If you look around you can
find it backed with hot-melt glue. Otherwise you
can use hide-glue just like they did before vaccuum
methods were developed.

Possibly you could use shellac as a hot-melt glue
too. I've been meaning to try that.

--

FF