Birch Slab Doors

[Jeff Bednar]

Hello,



Hello,


Last week, my dad and I built this cabinet for my garage. It is built from sanded birch plywood with 1x2 maple for the face frame.

I intended to use 3/4 in. sanded birch plywood for the doors (I already have the material) - each door will be approx 69x23" but I became a little concerned about the material warping. I want to find a way to make these slab doors work, rather than build them out of rails... I am wondering if three 1x2's turned on edge, spaced top, middle, bottom and screwed from the inside into the door would suffice to keep these doors flat?


Thank you

350298

[Jim Becker]

You could use wood for this, but you can also use inexpensive steel bars that you drill and screw to the back of the doors to help keep them true. And that takes up less space than the 1x2 you propose. I had an issue with this on a recent buffet/hutch project with the larger upper unit doors and the steel made things dead flat again.

[Jim Dwight]

Steel also doesn't warp.

Seems like a waste of what I assume is 3/4 plywood to use it for doors, however. I can make flat panel doors pretty quickly out of a bit of softwood for the frame and 5mm luan for the panel. You could also use Masonite for the panel. They would be cheaper and more likely to stay flat. If you are determined to use 3/4 sheet goods, nasty old MDF takes paint well and is a lot less likely to warp than plywood.

I make flat panel doors using a cope and stick bit in the router table. The little stub tenons don't look like much but have always worked for me. But on a flat panel door, you can glue the panel making the strength obviously at least adequate.

[Jeff Bednar]

Thank you both. I bought a sheet of 3/4" factory finished birch. I wanted to use that for the doors because the cost was identical to the raw birch. Rail/stile doors will be a future project.
Would you suggest just basic angle iron? Any particular way I should screw it to still allow for movement of the wood on the doors?

[lowell holmes]

I've never had doors made of 3/4" plywood warp. That doesn't mean it will not. I have 3/4" doors with lip mold on my kitchen. They are over 20 years old and no warping has taken place.

[John Lankers]

I agree with steel or aluminum bars as support, a full length piano hinge on each door would add further support.

[Ole Anderson]

I would think prefinished ply might be of a better quality than what is found (unfinished) at the big box store? Use and if it starts to warp, then try the angle iron fix.

[Mark Wooden]

I'm with Ole-
Before going to the trouble of screwing metal angles to the doors- while plywood ain't what it used to be(especially the chinese stuff) if you start with reasonably flat stock, prefinished two sides and use euro style cup hinges- I'd recommend five on a door that size- you should be able to keep the doors servicable and good looking. I've adjusted warp out of doors more than a few times.
Most important will be to seal the cut edges with a varnish of some sort, even if you're going to edgeband them, seal first.

[George Bokros]

Most important will be to seal the cut edges with a varnish of some sort, even if you're going to edgeband them, seal first.

Will edge banding adhere to the sealed surface? What would you use to seal them, most glues even the iron on edge banding will likely not adhere IMO.

[Jim Becker]

Would you suggest just basic angle iron? Any particular way I should screw it to still allow for movement of the wood on the doors?
I used flat steel...about 3/16" thick...from Home Depot for this. Not the angle material. The flat steel of that thickness is more than stiff enough to keep a slab of 3/4" plywood flat and it doesn't stick out much. ;)

[Robin Frierson]

I think your plan to use 1 x 2 cleats will work fine and save you a trip to have to buy metal and drill it.. Tops like blanket chest also usually need cleats so its not just plywood that warps.

[rudy de haas]

I have an old, 1970s, cabinet that has 1/2" plywood doors, about 48" x 22" (I have not measured it, guessing here; too lazy to go look). It's painted (green!) but otherwise ordinary early 1970s plywood. No warping..

Humidity changes should not cause birch ply to warp much, if at all - but weight could have negative effects if you have heavy doors, frequent use, and only euro-style hinges inset in the wood. Why not save your nice 3/4" ply for something else, and see if the local box store has some 1/2" birch cut-offs you could get for cheap and put on using piano hinges?

[lowell holmes]

I re-iterate, my 3/4" birch plywood doors have not warped.

Go to a lumber supplier like Houston Hardwoods, or Clarke's Hardwood Lumber Co. They are in Houston Texas.

I'm sure you have quality wood suppliers in your area. Do not buy plywood from the shopping mall stores.