How do i flatten a piece of plywood? should i soak it first?

Answer 1

If you're going to use the plywood to cover a studded wall, or a box frame, etc, anything with any support at all, then the plywood will assume the shape of the material it's being attached to. If the wall is flat, the plywood will be flat once attached, if there's a slight bow to the wall, or box or whatever, the plywood will most likely assume that shape, (unless it's very thick plywood). If you just want your plywood to be flat, then you'll need to find a couple 2 x 4's, position them either on the length sides or the width ends, depending on how the plywood is warped and put a weight in the center, sufficient to bow the plywood the other way.
Check it after a day or two and see if it's straight enough for you. If not, repeat the process. Whatever you do, don't wet it. Water isn't good for plywood.

Answer 2

It mignt straighten out when you get it cut down to size and incorperated in what you are build that is if it is not warped to bad other wise I would just get a new sheet Cabinet grade birch and oak are like $54 dollars a sheet. I would not get it wet Because when they make the stuff they glue a buch of layers together and then use a large amount of pressure to push them together. If you get it wet the Crapy inside layers will swell with the water and the plys will delaminate. when I worked in a cabinet shop we always stored our plywood standing up and it never got warped good dry conditions would help also.

Answer 3

I agree entirely with nicnic. I would have thought that the plywood will take the required shape when fixed to whatever you are making. Even laid flat with the bowed area upward a weight will keep it flat.

Answer 4

If it is dampened and weight set on it it should straighten out.