Veneer over solid wood

[Steve Demuth]

This falls into the category of "damn, was that dumb." I glued up some panels, 1/42" inch walnut veneer on one side and 1/42" backer veneer on the other of a solid 1/5" (corrected from 1/20") Red Oak core, using TiteBond III. They are 15" X 26" panels, veneer grain running the long direction, core grain the short. Normally I veneer over a composite substrate, but I was trying to make this piece using wood from the home place for one of the brood, and somehow managed to get all the way through making the cores and gluing them up before thinking about the consequences of wood movement. I blame age and the very good history book on tape (The Crusades: The Authoritative History of the War for the Holy Land, by Thomas Asbridge), read nicely to me by Alexa**.

Anyway, the oak in the core is very dry (originally kiln dried, now at 6% moisture (http://www.sawmillcreek.org/showthread.php?252885-Wood-(drying)-in-the-shop)), and I'm wondering what's going to happen if I use these panels. I can imagine 3/8" or more expansion in the direction of the veneer's long grain if the piece goes in an un-airconditioned house. Is that going to cause separation of core and veneer?

** I highly recommend the Amazon Echo / Alexa for the shop. I don't generally like talking to computers, but being able to start and stop your music or other audio with a simple voice command when you need to concentrate and/or are going to use a power tool is great.

[John TenEyck]

1/20" thick core? Really? If that's the case, you made plywood, and it will be fine.

John

[Steve Demuth]

Good catch. Meant 1/5". Total thickness is 1/4" with the two plies of veneer.

[Jeff Duncan]

So a bit tricky to answer easily. In the old days veneer was always applied to a solid wood core....and to some extent still done so today. Ideally one would use quarter sawn wood known for stability, back then many woods could have been used....these days, not so much. For instance old growth poplar was a wood veneered over pretty regularly, but new growth poplar is not the most stable wood and I wouldn't recommend it. These days if I glue up my own panels it's either over something like quarter sawn mahogany, which is expensive so only used on something worthy, or mdf, which is cheap but flat. Now for a 1/4" panel I'm guessing these could be for door panels? If that's the case and the oak was properly dry and reasonably flat you should be fine. At 26" wide for the core your probably not going to move more than 1/8" unless you submerge them in the ocean. And that size shouldn't warp too much even using what I'm guessing was plain old flat sawn? If they are not for door panels, (i.e. held in place), then it's a different story and left to their own have a lot of potential to want to move, (warp), with humidity changes.

good luck,
JeffD

[Steve Demuth]

Jeff,

Thanks for the insight. They are not actually going in a door, but for practical purposes you could think of them that way - they're going into 3/4" rail and style frames. I selected the oak to lean toward quarter sawn, but wasn't too fussy - it's more radial than flat grain, but not true quarter sawn.

[Ken Combs]

I'll bet they will be fine. The reason I say that is this: In my house are several cabinets made from what was called 'lumber core plywood' back in the 50-70s. Haven't seen any recently but the core is about 9/16" solid wood with a cross band layer of junk veneer followed by a finish veneer oriented in the same direction as the core lumber. So that cross band is in the same direction as your veneer, and hasn't failed.

These were installed about 1966. still here, no problem.