How to flatten plywood (or does it matter)?
 

I am making a 9" by 12" box. Top is hardwood raised panel, box is
hardwood, base is hardwood ... but I was planning to use a piece of
1/4" plywood (walnut) for the bottom of the box.

This plywood bottom will be glued into grooves rabbitted into the
inside top edge of the base. The box then glued on top of the base /
plywood. The box's stock thickness is a hair under 1/2 " ... so about
half of that sits on the plywood with the other half overlapping the
base.

Here's my question: the plywood sheet from which I cut my bottom
piece was a bit curled ... when I cut out the roughly 9*12 bottom
piece it curled even moret. The edges now curl up about 1" when it's
just lying on my workbench. I am ready to glue/clamp this plywood
down on my base ... but now I'm worried that this curling will cause
trouble for my box on down the road. Do you think the glue will hold
up over time? Or will the constant pull of the curling eventually
cause something to give?

Rather than just glueing it "as is" I'm wondering about "plywood
bending" (never tried it, but keep hearing about it). I wonder if I
could use the same steam techniques used to bend plywood to just
flatten out this little piece? If so, wonder exactly how I should go
about it? Just steam it for a while or will the piece still require
soaking (even though I'm not bending it much).

Thanks,
Adam

(sitting here scratching my head ... the whole POINT of using plywood
in the first place is to avoid this kind of problem!)

Cut your plywood to size. Now lay the piece on a flat table. How much
weight does it take to bring it to flat?

I suspect the answer would be less than a pound. if the edges are
constrained in the dado, it will hold the panel flat, not to worry.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.


"Adam White" wrote in message
...

I am making a 9" by 12" box. Top is hardwood raised panel, box is
hardwood, base is hardwood ... but I was planning to use a piece of
1/4" plywood (walnut) for the bottom of the box.

This plywood bottom will be glued into grooves rabbitted into the
inside top edge of the base. The box then glued on top of the base /
plywood. The box's stock thickness is a hair under 1/2 " ... so about
half of that sits on the plywood with the other half overlapping the
base.

Here's my question: the plywood sheet from which I cut my bottom
piece was a bit curled ... when I cut out the roughly 9*12 bottom
piece it curled even moret. The edges now curl up about 1" when it's
just lying on my workbench. I am ready to glue/clamp this plywood
down on my base ... but now I'm worried that this curling will cause
trouble for my box on down the road. Do you think the glue will hold
up over time? Or will the constant pull of the curling eventually
cause something to give?

Rather than just glueing it "as is" I'm wondering about "plywood
bending" (never tried it, but keep hearing about it). I wonder if I
could use the same steam techniques used to bend plywood to just
flatten out this little piece? If so, wonder exactly how I should go
about it? Just steam it for a while or will the piece still require
soaking (even though I'm not bending it much).

Thanks,
Adam

(sitting here scratching my head ... the whole POINT of using plywood
in the first place is to avoid this kind of problem!)

If the edges of a 9 inch by 12 inch piece of plywood are curling up 1 INCH
at the edges, you need to get another sheet of plywood.


"Adam White" wrote in message
...

I am making a 9" by 12" box. Top is hardwood raised panel, box is
hardwood, base is hardwood ... but I was planning to use a piece of
1/4" plywood (walnut) for the bottom of the box.

This plywood bottom will be glued into grooves rabbitted into the
inside top edge of the base. The box then glued on top of the base /
plywood. The box's stock thickness is a hair under 1/2 " ... so about
half of that sits on the plywood with the other half overlapping the
base.

Here's my question: the plywood sheet from which I cut my bottom
piece was a bit curled ... when I cut out the roughly 9*12 bottom
piece it curled even moret. The edges now curl up about 1" when it's
just lying on my workbench. I am ready to glue/clamp this plywood
down on my base ... but now I'm worried that this curling will cause
trouble for my box on down the road. Do you think the glue will hold
up over time? Or will the constant pull of the curling eventually
cause something to give?

Rather than just glueing it "as is" I'm wondering about "plywood
bending" (never tried it, but keep hearing about it). I wonder if I
could use the same steam techniques used to bend plywood to just
flatten out this little piece? If so, wonder exactly how I should go
about it? Just steam it for a while or will the piece still require
soaking (even though I'm not bending it much).

Thanks,
Adam

(sitting here scratching my head ... the whole POINT of using plywood
in the first place is to avoid this kind of problem!)