I bought some one-quarter inch ply for backing on a job I am working on, stood it upright in my shop, and now it is warped, curling actually. I don’t have the space to store it flat. So how do I get it to go back to flat so that I can work with it? It is white oak on one side, now the concave side.
-Bob
Replies
Artistinwood,
I have yet to see the sheet of 1/4" ply that is even remotely flat, especially when there are different materials on the two faces. This material must be supported in a framework of some kind to achieve flatness, such as when used in a back panel.
Plywood will never be flat, if it happens to be flat right now don't count on it staying flat..
When you say you will use the 1/4" for backing , it sounds like you will be fastening it to the back of a cabinet or something , right ? If so then it really will not matter if it is flat right now when it gets put against the back of whatever it will be flat .
good luck dusty
True, it will be installed in the back of a cabinet, and so I can get it to go to flat at the time of installation.
But my problem is that it is now a 4X8 sheet of very curved ply and I have to cut it down to size first. To do that, it has to be flat.
What if I dampened it a little on the convex side? Would that help to get rid of the warping for a while, just enough so I could work with it?
-Bob
Dampening the concave side will usually cause the sheet to flatten out temporarily so that you can work with it. An unpainted concrete floor will often be damp enough to achieve the same effect, just place the sheet on the floor, convex side down, and place some weight on it to get the plywood against the concrete so it can absorb some moisture. In a few hours, to overnight, the sheet will probably uncurl.
Occasionally you can get a poorly made sheet that develops a very rigid curve, these are best scrapped or returned for a replacement since they will tear themselves loose from the cabinet or exert enough force to twist the entire piece.
John W.
Edited 10/11/2005 10:00 am ET by JohnWW
Should that be "wet" the concave side!!
Dampness, such as from a concrete floor, or placing damp but wrung out towels on the concave side will work as well, though a bit slower. Wetting the wood can cause too much water to be absorbed which can cause the panel to reverse curve and wetting can cause grain raising and staining problems on the veneers.
John W.
It was just that you had written Convex and I think you meant concave!
My mistake, I meant to say that the concave side needs needs to have moisture added. I've edited my first response to correct this. Thanks for catching my error.
John W.
How are you going to cut it? TS or hand saw.. May want to just use a 'skill' saw with a clamped down guide..IF warped in just one plane you should still be able to get a nice cut on your TS if you are careful... Almost all the ply I cut is 3/4 or better.. Some 1/4 for backs which usually warp somehow.. Clod like me can cut it straight so yours should be perfect!
Edited 10/8/2005 11:41 am ET by WillGeorge
Hi Bob ,
As Will said , you should still be able to cut a panel that is not flat , really give it a go , and see what happens , I do it all the time on the TS .
good luck dusty
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