[DeanK]

Hey all. I was digging through my pile of plywood scraps yesterday looking for a nice straight and flat piece to use for a router jig. It was more of a challenge than I anticipated unfortunately. Most of my plywood scrap stock is big box construction grade stuff, not expensive cabinet grade, but my question applies for any plywood really. How do you guys store this stuff and keep it from bowing or otherwise becoming non-flat?

My work area is in the basement, which is dry and temperature controlled. I don't have space to store large sheets flat, so they're standing on end leaning against one wall. My stuff isn't terribly bowed, but just enough to make me think twice about using it for anything that needs to be square or flat. I imagine over time gravity is kinder to sheets that are stored flat. Any suggestions for how to keep it flat for longer than a few months? Keep them clamped together? Any creative ways to flatten out 4'x4' or 2'x4' pieces. I've been wanting to make some drawers for my workbench for sandpaper and router bits and such and I'd like to use some of the stuff I have and not have to buy new...

 

[Dave Paine]

My personal experience is that some plywood will warp independent of the method of storage. I have some 2ft x 4ft pieces of birch plywood, many thin layers, which has some bow as purchased.

The only sheet good I can rely on being flat seems to be MDF.

I made a rolling lumber cart, pictures in this thread. It allows me to store the sheet goods on the long edge and close to vertical. Some of the sheets have a good bow, especially the construction grade plywood.

http://www.woodworkingtalk.com/f27/rolling-lumber-rack-43282/

 

[cabinetman]

No matter how its stored, if the floor is damp, wet, concrete, etc., use wood strips under it to keep it up and allow airflow under. Plywood is best stored flat. If that isn't possible, the next best way would be on the long edge, and as vertical as possible. If you have many pieces, stack them together and clamp them tight. I use handscrew clamps, and the bundle will stand by itself vertically.

.

 

[Brian T.]

In the back of the local Windsor Plywood franchise, there must be 40 bins of plywood sorts of things.
All flat & horizontal, lowest 6" off the concrete floor. Out front is 100+ species of woods from board-room
table slabs ($8K) to 12" x 16" x 60" yellow cedar, bowl blanks, ebony, you name it.

My suggestion is to trim all scrap(?) so it can rest flat.
Don't buy any until the day you know that you will cut it into a project
or it's an application where you don't much care.
I am well-stocked with those bananas.

 

[Fred Hargis]

I've been storing it on end for the last several years. Before that, I had stored it on edge. In both cases I made sure the sheet was standing vertically as much as possible, and it was tightly ganged with other sheets. I never had only one or two sheets to store, but if I had I would have used some lumber to stiffen it....and it would have still been on edge. I know flat is better, but most of don't have that kind of space.

 

[DeanK]

Well, there may be no hope for the pieces I already have, but I will do a better job of keeping them more vertical and try clamping together like sized pieces. I have a couple 4'x4' pieces, a few 2'x4' pieces and other random cutoff sizes. I realize that those smaller pieces always find their way in-between the larger sheets, giving them room to lean and sag. A real lumber rack (or at least a better system of organizing stock) may be in my future. Dave, I really like your mobile cart. Something of that magnitude would have to wait until I get my new garage, hopefully this summer.

 

[Hammer1]

Construction plywood is a different animal than cabinet grade. It's not likely to stay flat regardless of the storage procedure.

 

[Manuka Jock]

yeah its' a bugga the way ply adopts shape of the corner that it is placed in .
For long term storage , a press made from two sheets of MDF might work

 

[aaronhl]

I use a lot of plywood 1/16" thick through 3/4" all types good and bad...my basement is damp and somewhat cool so I put all the wood upstairs under my bed.