New to veneering. Neccessary to apply to both sides?

[dirk martin]

I carve signs as a hobby, when I have time.
I've also got some stunning burl veneer, that looks stunning when bookmatched.

So, I think I want to apply some bookmatched veneer to some baltic birch plywood, and then carve a sign (CNC).
Do I HAVE to veneer the back side of the board to prevent warping?
Is contact cement fine?

[Jim Tobias]

Not familiar with carving, but yes, veneer both sides and I use either Unibond 800 or Better Bond Cold Press glue. I have never tried it, but have read a lot of posts saying that you shoul dnot veneer wiht contact cement.

Jim

[mike holden]

Yes, you have to veneer both sides.
Usually you use an inexpensive plain veneer on the back side.

Mike

[johnny means]

No, the fact that you will be carving out one face means that any bowing would then happen in the direction of the uncarved face . Think of your veneer as the string on a bow , once you cut that string all tension is gone and your bow straightens out.

T

[Montgomery Scott]

backer is not necessary when the substrate is ply; there will be no warping unless you have some thin ply. You can use contact cement if you have paper backed veneer, but not raw veneer.

[Chris Fournier]

I certainly would glue a backer to your proposed set up. Plywood is stable because it has plys that are balanced from front to back. You need to continue this theme, gluing up 90 degrees to the face veneers of the plywood. Certainly you won't glue a nice burl to the back and even this is an imbalance in the finished veneered piece.

Don't believe me because others say don't bother? Take a spray bottle and mist water on one face of your proposed ply core. Let it sit and then check out the movement of the plywood. You will do just this if you apply glue to one face and then veneer. Sure you could glue on the burl and hit the back face with water and then press but this is no fail safe. Veneer both faces and keep the glue up in the press overnight. Once out of the press stand the glue up on edge away from air currents and direct light. This process will yield the best results. You could use PVA glue but I would consider plastic resin glue if I was doing the work. You can bank on this free advice.