What do you do?

[ozarkhillbilly]

I stack cut this piece 3 deep, with 1/4 bb plywood and its 11x14, after working on it a few hours, I put it up for the night, when I came back to work on it today it had warped pretty badly, It became a nightmare at times cutting it, pushing it firmly to the table made it hard to manuver the piece, and at times it wanted to vibrate severly. I found if I let it bow the way it wanted and just gently and slowly fed it into the blade, the vibration was reduced and it cut pretty much as it normally does. This is pretty much the first time I have encountered this before, and was wondering what you all do when this happens?

Anyway I got thru it with no mishaps, and pretty happy with the way it turned out.....

[lucky788scroller]

try dampening the woodon the cupped side just a smidge. BBply doesnt usually warp like that for me though. I recently did a piece of ash that did all sorts of funny stuff as I cut it, and I almost gave up. The only thing that saved it was probably a little extra effort, and a few carefully chosen words. Dale

[SharonW0111]

Billy this is what I did when that happened to me-- Lay something heavy on top of your piece- be sure not to use anything directly against it that will scar it-the more weight you . lay it like this for a day --then add more weighteach day until it is straight- this will fix the problem ..In future lay something heavy on a unfinished piece when you put it up for the night--this will prevent it from warping .
Before I stopped sawing I had a few patterns I was going to do ( sorry Bob but my piece of the quilt isn't going to make it ) anyway-- I had the main board all pretty and sandeded and so I tacked the corners to the backer board -since these were for the quilt I had them fixed just right- and I taped the pattern to the piticular board I wanted to use -they are still that way and havent warped a bit.I hope someday I can finish them cause they were very special- one was a portraite of Christ head looking down another was his hand outstretched to a childs hand .. maybe God will see me fit to be able to cut them out before the deadline.. I sure hope so.
anyway sorry for the rambling -- hope this helps..
Sharon

[ozarkhillbilly]

This is the 1st time bb plywood has done this to me, I bought it at Lowe's, so I know it's not the best grade, I was thinking perhaps it was due to the amount of wood I had removed in the center.....? It's been raining here the past few days also so perhaps the humidity....?

Well at least it didn't turn into designer firewood

[sheltiecarver]

Bill,
I certainly don't know your Lowes, but the one closest to me has BIRCH plywood, but not Baltic Birch plywood. The cheaper birch ply - or make that a bit less expensive - has a lot fewer plies, and the wood just isn't as clear.
The pieces of real BB ply that I have worked with don't warp much at all, but I cut some practice boards for a pyrography class from the birch ply, and they warped like crazy. Looking back, it was during a rainy spell after a long dry spell. Some of them I saved using Sharon's method, and some did become firewood.
I'd say from the high quality of your finished project, that you did just the right thing.
Sandy

[Marcel in Longueuil]

Moisture

Billy,

Here are my thoughts on this:

The warping is usually caused by uneven gain or loss of moisture. I am guessing that you let the piece lie flat on a metal or wood surface for the night. The exposed face aborbed the humidity from the air, but not the face lying down, causing the moisture unbalance and warping.

Turning the piece over for a night might have fixed the problem, so might have first putting a damp cloth on the unexposed surface for a few moments followed by weight on top.

What you want to do is balance the moisture content on both sides (actually throughout the piece) so that it will not warp while drying, and using some form of retraint to straighten the warping.

To prevent this, you may want to use the same method used to store solid wood: stickering. When you put your project away for the night, make sure it is not fully lying on a surface, that there is something allowing air circulation on both sides of your piece.

If you feel your piece needs the support all over, how about getting a piece of pegboard (or windowscreen) on blocks and laying the piece on it.

OR

I'm full of it and it was internal stress that got released when you took some of the material away, and there is no solution to that

Regards,
Marcel

[ozarkhillbilly]

Sandy, sorry about my post, your correct it is just birch ply....

[minowevie]

Billy,

Here are my thoughts on this:

The warping is usually caused by uneven gain or loss of moisture. I am guessing that you let the piece lie flat on a metal or wood surface for the night. The exposed face aborbed the humidity from the air, but not the face lying down, causing the moisture unbalance and warping.

Turning the piece over for a night might have fixed the problem, so might have first putting a damp cloth on the unexposed surface for a few moments followed by weight on top.

What you want to do is balance the moisture content on both sides (actually throughout the piece) so that it will not warp while drying, and using some form of retraint to straighten the warping.

To prevent this, you may want to use the same method used to store solid wood: stickering. When you put your project away for the night, make sure it is not fully lying on a surface, that there is something allowing air circulation on both sides of your piece.

If you feel your piece needs the support all over, how about getting a piece of pegboard (or windowscreen) on blocks and laying the piece on it.

OR

I'm full of it and it was internal stress that got released when you took some of the material away, and there is no solution to that

Regards,
Marcel

Marcel. you are not full of it. that is right on. it is the absence of moisture.(on one side) and on plywood. that you have already cut. can be a probleam. yes you do need to add moistuer. and then brace it some how.
I add some wood lock . or some minerale spirats. then clamp it down. eather with some spacers. flat. or standing up.(with some spring clamps) with something to , space or brace it. If you put some wood inbetween it. it can hold the moister in. so be sure to make it a spacer, that can let the air flow. might mean putting alot of spacers. to let air flow.(just some little pieces of wood scraps. like 1/8 or 1/4. scraps) (1/8 or 1/16th)but you don't wont it to mold on you. so plan what you are willing to do. your right, it will bounce around on you big time. the other thing . is something i hate doing, is use your , hold, down bar that wil give you some controle. hope this helps. your friend Evie

[ozarkhillbilly]

Thanks guys for all the input, Sharon if your reading this and haven't noticed by now I've sent you a PM.

Bill