Replies

1. 
   jharveyb | Apr 08, 2023 09:53pm | #1

   I have some experience gluing 1/8" tiger stripe maple to plain maple. In theory you don't need a backer veneer, as you are basically gluing solid wood to solid wood of the same species with the same grain orientation. HOWEVER, when we did this with maple, the water in the Titebond glue distorted the wood, swelling the veneered side, with the glue setting with the board cupped. The cupping never completely went away as the water dispersed. I highly recommend that you not use a water based glue. I would use an epoxy suitable for wood.

2. 
   BillieRuben | Apr 08, 2023 10:49pm | #2

   Unless you're backing the veneer to something very very thick you'll need a veneer on the opposite side.

   I have glued plane shavings to a 5mm board and had it cup.

   What happens is that when you add the glue it swells the wood in the direction perpendicular to the grain , and as it dries the moisture escapes and pulls the piece into a curve.

   This even happens when using paper!
   When bookbinding, a cover will become convex after covering it in the bookcloth, then the paste down (colloquially called endpaper) or dubleau (not sure how to spell this?) is pasted to the inside and it pulls the cover back into a flat shape.

   If you want to try it with 2 layers though, I don't see any reason you couldn't give it a go with veneer on just one side, if it does end up warped, you can just add the piece to the opposite side after the fact.

   You'd need the grain lines running in the same direction for 2 pieces to work though, else it will cup for sure. Which might mean your ply isn't as good for a backer.

   I reckon you have the most chance of success by applying glue to both mating surfaces. And letting the glue sink in for a bit before bringing them together (letting the whole veneer get moisture evenly, not just the side with glue on it). The veneer will cup after applying the glue but it start to flatten out as the moisture seeps in through the whole leaf, then it's ready. Obvs you will need a glue with enough working time for this. Else maybe you could lightly dampen the face sides of the two pieces?

   Do a few test strips for sure no matter what you do, running each direction.

   Could you just do three layers, using something cheap in the middle? And save the cherry for the faces.

3. 
   Pali | Apr 08, 2023 11:11pm | #3

   Thanks. I'm going to play it safe and add a same thickness (3/32") backer veneer. It's easier than trying to retro fit a third backer layer if two layers don't work. The secondary wood is 3/4", I bet not thick enough to guarantee not cupping, especially since I was not attentive to grain orientation. My Woodslicer resaw blade will get an extra workout. Thanks again!

1. 
   BillieRuben | Apr 08, 2023 11:12pm | #4

   I hope you show off the results! ☺️☺️