Unwarping 1/8 ply for laser cutting

[Weston Porter]

So once a month I borrow a truck, buy some 1/8 baltic birch sheets and spend an hour cutting them into 12x20 blanks for laser cutting. The boxes I make with these blanks have a lot of cuts which tend to not to penetrate in some areas or char others with warped stock and the assembled pieces are held together with tension and don't fit together properly with warped stock.

I live in Houston and it has the humidity of swamp. If the boards aren't already warped when I buy them, then they warp on the ride home, or while being stored.

I've searched around and posted elsewhere without much luck, I need a method for straightening these blanks. I've envisioned building something like this (http://www.talasonline.com/photos/bookbinding/Quicknip.jpg), where I can individually steam and stack 10+20 sheets under pressure and then bag when dry. Will that do the trick? Is there an easier way?

[Joe Pelonio]

Your contraption would be great to use for storing them when cut, if they are already straight. I have such a thing myself that I use for gluing and have found that even a week will not remove warping. I have managed to straighten in it by adding another piece across the middle to make it bend the opposite way from the warp, but then that leaves a mark so I had to also put a sheet of rubber in it.

It might work if the pieces still have a high water content when put into it. I usually save the warped pieces to do smaller work where it won't matter as much. Might be worth getting a dehumidifier for your shop.

[Kev Williams]

I make business cards out of alder veneer, which is crazy warped because they roll it up like toilet paper. The way I straighten the pieces I'm about to engrave is to run a damp rag over the sheet just before engraving. Lays down nicely. Obviously this stuff isn't 1/4" thick, but I'm just wondering if misting the wood a few minutes before you work it might help?

[Mike Null]

You should call Mike Kowalczywk. He's in Houston and has supplied many of us with BB for a long time. http://www.displayideas.com/About%20Us.htm

[Matt McCoy]

Hey Weston: If the sheets are curling, you can use a brush to wet the back of the material and then put it under flat pressure overnight. For severe warping, it would probably be best to steam them if you can.

If the stock is warped when you purchase it in sheets, it may not be stored properly and I would look for a different supplier. After you cut down your sheets to 20 x 12", I would stack them like veneer and put a heavy piece on top to keep them flat. I use Thick MDF.