bending thin hardwood

Sonny <[email protected]> wrote:

> Rather than a plywood jig, just prop the ends of the panel on 1" boards
and clamp the middle of the panel to produce the curve. I don't think your
chair's curve deflection is quite 1" and you will have some spring back of
the panel, when you remove it from the jig.

It's actually 2" deflection at the center of the curve. Maybe it still
could be clamped in that way? I thought that pressing on it with a
straight board or clamp might dent the veneer.

> Wet/soak the panel in hot water before bending it. That red oak might warp
a tad, too.
>
> Also, the ends of the panel might split, during drying, depending on your
panel. Cut your panel 1/2" to 1" larger (width X length), bend it, then trim it to fit the chair. The trimming would get rid of any splitting, also, if need be.
>
> If your red oak panel has been kiln dried, it might not bend properly.
Air dried lumber is best for steam/wet bending. Is your panel plywood or is
it a solid cut of red oak?

It's actually some other kind of wood with an oak veneer - I didn't even
notice that till now! It's meant as a cabinet piece, something I got at
Lowe's. I wetted a scrap of it - not soaking, just wetting - and it did
bend fine, although I didn't keep it bent while it dried, so I don't
know to what extent it would keep the curve. It dried without cracking.

Laura

On Thursday, December 27, 2012 5:40:12 PM UTC-6, Graven Water wrote:
> It's actually 2" deflection at the center of the curve. Maybe it still c=
ould be clamped in that way? I thought that pressing on it with a straight =
board or clamp might dent the veneer.=20

At first, I thought it was a child's chair.

> It's actually some other kind of wood with an oak veneer - I didn't even =
notice that till now! It's meant as a cabinet piece, something I got at Low=
e's. I wetted a scrap of it - not soaking, just wetting - and it did bend f=
ine, although I didn't keep it bent while it dried, so I don't know to what=
extent it would keep the curve. It dried without cracking. Laura

It is likely kiln dried wood. Multifold a towel and apply that to the pan=
el, then your clamp or clamping board, to prevent your panel from becoming =
marred. Wet it and clamp it with a little deflection, at first. After an =
hour or 2, wet it some more and clamp down some more... more deflection. A=
fter another hour or 2, wet it and clamp down some more..... Creep up on th=
e amount of deflextion you need, then deflect a little more, to accommodate=
spring back. You'll have to guess at how much spring back there may be.

Rather than repeated wettings, you might wet it and place a wet cloth over =
and under the "whole". When the cloth(s) dries too much, re-wet it/them. =
Your clamping process may require a 8-12 hour time period... go slow. It m=
ay be a hit or miss proposition with that ply panel.... and hope the plies =
don't separate/come apart in places.

Once you get to your max deflection, allow the panel to dry, in the clamped=
position, for another day, at least.

Good luck.
Sonny

>=20
> Should the plywood mold have an exaggerated curve? =20

Yes. =20

Rather than a plywood jig, just prop the ends of the panel on 1" boards and=
clamp the middle of the panel to produce the curve. I don't think your ch=
air's curve deflection is quite 1" and you will have some spring back of th=
e panel, when you remove it from the jig.

Wet/soak the panel in hot water before bending it. That red oak might warp=
a tad, too. =20

Also, the ends of the panel might split, during drying, depending on your p=
anel. Cut your panel 1/2" to 1" larger (width X length), bend it, then tri=
m it to fit the chair. The trimming would get rid of any splitting, also, =
if need be.

If your red oak panel has been kiln dried, it might not bend properly. Air=
dried lumber is best for steam/wet bending. Is your panel plywood or is i=
t a solid cut of red oak?

Sonny

On 12/27/2012 4:35 PM, Graven Water wrote:
> Hi, I'm repairing a curved chair back, pic is at
> http://camoo.freeshell.org/chair.jpg
>
> I have some 1/8" thick red oak, there will be pieces about 15" x 7"
> screwed to the front and back of the frame that you can see in the
> picture. I cut one of those pieces, it bends fine to the curve of the
> frame. The grain of the oak will be horizontal on the chair.
>
> The oak should be bent to the right shape before attaching it to the
> frame, otherwise it'll put a lot of stress on the frame.
>
> I think I know roughly how to do this: I would trace out the curve of the
> chair back on 3/4" plywood and cut it to that curve; then clamp the oak
> between pieces of curved plywood to bend it.
>
> How about wetting the oak before clamping it into the plywood mold? I
> tried this on a scrap piece and that seemed to help it bend. Should it be
> re-wet? I've heard of steaming wood to bend it, but that seems rather a
> pain.

Water is needed when heating wood to avoid scorching the wood. I assume
you are planing on gluing up a bunch of 1/8" oak veneer then clamping it
in a mold until the glue dries. You should not need to wet anything
other than with glue.

> Should the plywood mold have an exaggerated curve?

If steam bending you would, don't think so with gluing up thin strips.
Steam bending you need to heat the wood to at least to 200 degrees to
soften the cells so they can bend. The steam aids in transferring heat
w/o burning/scorching the wood. Oak is pretty flexible in 1/8" strips
so you should have no trouble just gluing/clamping a bunch in a mold .

Try to get straight grain with little or no run out, although I wouldn't
worry about that much with thin strips and just a small bend as you are
doing.

To permanently bend 1/8" strips alone, you could just heat it up with a
heat gun and bend over a curved pipe or something. In that case, you
might want to soak the wood first to prevent scorching.


--
Jack
Add Life to your Days not Days to your Life.
http://jbstein.com

On Thu, 27 Dec 2012 16:35:14 -0500 (EST), [email protected] (Graven Water)
wrote:

>Hi, I'm repairing a curved chair back, pic is at
>http://camoo.freeshell.org/chair.jpg
>
>I have some 1/8" thick red oak, there will be pieces about 15" x 7"
>screwed to the front and back of the frame that you can see in the
>picture. I cut one of those pieces, it bends fine to the curve of the
>frame. The grain of the oak will be horizontal on the chair.
>
>The oak should be bent to the right shape before attaching it to the
>frame, otherwise it'll put a lot of stress on the frame.
>
>I think I know roughly how to do this: I would trace out the curve of the
>chair back on 3/4" plywood and cut it to that curve; then clamp the oak
>between pieces of curved plywood to bend it.
>
>How about wetting the oak before clamping it into the plywood mold? I
>tried this on a scrap piece and that seemed to help it bend. Should it be
>re-wet? I've heard of steaming wood to bend it, but that seems rather a
>pain.
>
>Should the plywood mold have an exaggerated curve?

Yes, overbend since it will spring back. Use trial and error if you
have the time.

Laura, steaming the wood might save you a lot of headaches.

Alternatively, look into laminating the backs yourself if you have a
bunch to do. Build jigs and clamp them to make the proper curve, then
finish cutting to size.



--
You can either hold yourself up to the unrealistic standards of others,
or ignore them and concentrate on being happy with yourself as you are.
-- Jeph Jacques