Warped wood - need advice

[Dave Haughs]

I did some searching and it seems I'm not alone in my battle but my problem today is a bit odd, to me at least.

I'm making a scrapbook/photo album cover set for my wife. I've made them out of zebra wood framed in walnut. The zerbra wood was resawn and bookmatched. Due to the good old midwest and the crazy weather we get here the covers bowed during construction. I could flip the boards and let them set and they would bow the other way. I was able to wet the bowed side and let them flatten then hold them flat with weights when I wasn't working on them. All was well and they held up fine bringing them inside (shop is only heated when I am in it). Then today I thought I was in the clear and I went ahead and slapped some poly on them. I put it on both sides and layed them on a make shift bed of nails to dry flat and took them in the house. I came home tonight and one is still pretty flat but the other warped bad. Its not the typical bow I got before, this time it pulled up at two of the corners.

So I am assuming now there is nothing I can do to this piece that is finished short of sanding it down. These pieces are about 1/8" thick.

1) What cased this, I thought the poly would seal it and I would be in the clear?

2) How could I prevent this in the future?

3) Can I fix it? I was wondering if I could maybe sand down the side that the corners bowed out to and get it flat again then try it again? I am not sure how to force it flat while the poly is drying to keep it flat....

Any input is much appreciated.

[Steve Rozmiarek]

Was it water based poly? I wonder if you wait a day or two, if some of the problem will go away?

[Chris Padilla]

Wood: a fickle medium!!

Some times you just can't fight it. I'd suggest making another piece as these sound very prone to keep moving for whatever reason.

[Dave Haughs]

Its oil based Polly. I wonder if another piece is going to do the same thing? Thing is now both sides came out of the same piece so they have very similar grain and sort of "match" and look real nice together. THey just aren't playing well with me! I am weighting it down over night to see if it makes any difference at all, I doubt it will. It's the back cover so sitting on a shelf it would look fine, until someone pics it up and sees how bad it is warped. I guess I'll see how it is in the AM and maybe sand it down and try again?:confused:

Or go back to the drawing board and make it thicker maybe? I could redesign it, I guess and salvage the bookmatched zebra wood and back it with walnut to match the "frame" of it, only put the walnut grain going the other way and double the thickness? That sentence makes sense in my head but it may be hard to follow.... I hate to scrap these pieces, they do look nice.

[Chris Padilla]

Dave,

I think it is just the internal stresses of the wood doing funny things on you. Odds are another piece would be just fine but you never know.

If you plan to reuse the zebrawood as a veneer, slice it/sand it very thin: to no greater than 1/16". The thinner, the better is usually the name of the game with keeping veneers from moving. Also, use a glue that dries very hard like plastic resin: stay away from PVAs ("yellow" and white glues like Titebond I-III).

[Dave Haughs]

Dave,

I think it is just the internal stresses of the wood doing funny things on you. Odds are another piece would be just fine but you never know.

If you plan to reuse the zebrawood as a veneer, slice it/sand it very thin: to no greater than 1/16". The thinner, the better is usually the name of the game with keeping veneers from moving. Also, use a glue that dries very hard like plastic resin: stay away from PVAs ("yellow" and white glues like Titebond I-III).


That's interesting, maybe another piece is the way to go. Thanks for the advice.

The other piece did bow as night went on. The weight helped but I don't think it will solve it. I might go the veneer route since they both bowed a bit.

I've never worked with wood this thin, so this whole project has been a learning experience. I wonder if they just weren't even flat to begin with and I've just been fighting a loosing battle since then :confused:

[Joe Chritz]

You won't ever stop wood from moving. Sometimes you can control how it moves (by construction or how it is joined) but it will always gain/lose moisture and move around. It is possible it is internal stress but that usually (at least to me) shows up pretty early in the process. I have found that if the wood is gnarly (which causes all kinds of internal stresses) it will behave weird when it gains or loses moisture.

Resawing the wood to 1/16 or less, laminating up a piece of MDF then banding it would keep it flat. With solid wood it is always going to be hit or miss. Veneer's don't behave under the same rules as solid wood.

It is also possible it may straighten out once the entire piece acclimates to the new surroundings.

Joe

[Dave Haughs]

Well at the very least I am learning a lot from this project that I thought was a simple weekend project :D

I went out and went ahead and started making the backing (which is still visible) out of walnut and its so far so good. My bandsaw is kinda crappy and its operator is not that skilled so I used the planer to take these panels to 1/16" to make a veneer out of them. I'm going to go pick up some glue in a bit (all I have is titebond). Hopefully I can finish this project up this weekend since it's back to work on Monday. So far so good though, the walnut backer is flat as can be and has been sitting on a shelf out there in it's current state so I am not too worried about it warping, but I am not out of the woods yet. I'll keep you posted on this one.

Thanks for the tips and advice and mainly the encouragement, I was ready to throw this in the fireplace and give up last night:p

[Dave Haughs]

So an update. Even with the backing when I put the poly on they warped again. So I changed the design big time and it worked great on one but the other after my gluing and sanding battle ended up thinner and it warped so I am using the good one as the front cover and I am making a new rear cover and keeping them both about 1/4" thick to avoid this problem. Looks like I have a lot to learn when working with thinner wood.

[Steve Schoene]

One thing hasn't been mentioned and that is the necessity of NOT laying the wood down on the workbench for overnight. It should be stickered so the air can flow around it on all sides.

It also seems that the wood hasn't had a chance to equilibrate to the workspace humidity, and/or the humidity in the shop fluctuates widely, as in might in a shop where there is no heat overnight.

[Chris Padilla]

Dave,

Can you post some pictures? It would be interesting to see what you're working on...might help a few more synapses fire off to help you out.

[Dave Haughs]

One thing hasn't been mentioned and that is the necessity of NOT laying the wood down on the workbench for overnight. It should be stickered so the air can flow around it on all sides.

It also seems that the wood hasn't had a chance to equilibrate to the workspace humidity, and/or the humidity in the shop fluctuates widely, as in might in a shop where there is no heat overnight.

The shop is a huge problem as we just moved into this house this summer and I've been spending the time setting it up and haven't run power out there yet to be able to put in a heater. The previous owner had ONE 20 amp circuit that I use for the power tools but no 220 yet for running a decent heater around the clock. In addition to that if I work on things out there then take them inside the humidity changes....


Dave,

Can you post some pictures? It would be interesting to see what you're working on...might help a few more synapses fire off to help you out.

Yeah I'll post up some pictures tonight. I haven't been working on it much as until the other night I was busy finishing up a rocking horse. The good news is I do like the style of the new one better but it has its fair share of mistakes, but ya gotta learn somehow I suppose. years ago I made a box that was this thin and never had a problem with it but it was always inside even when I worked on it so the humidity never really fluctuated.

I'm not at all disappointed in this other than it took longer than I expected because of all the problems but like anything else you do for a first time I learned loads from it.