Veneering Over Pre-Finished Plywood

A discussion about how to go about preparing prefinished plywood for an application of paper-backed veneer to one side. September 29, 2014

I need to build some cabinets with prefinished maple on the inside and quarter cut walnut exterior. Can I run one side of the pre-finish through the wide belt and sand off the finish and veneer and then veneer that side with 10 mil paperbacked walnut? I'd be using a frame press with plastic resin glue. Would this create too much of an unbalanced panel? The parts will be typical cabinet sides about 24w x 30t and 12w x 34t.

Forum Responses
(Veneer Forum)
From contributor W:
I'm not sure about the balanced panel aspect but pre-finished ply isn't the flattest substrate available and that waviness would telegraph through walnut veneer. I usually use a piece of unfinished maple on classic core or MDF and veneer one side with the exterior veneer then finish the whole piece.

From the original questioner:
So waviness aside have you found veneering one side of a panel that has both sides veneered already caused any problems?

From contributor W:
I have never had a problem. I probably would not do it on a door but a cabinet part that is fastened to other parts is alright by me.

From the original questioner:
Thanks Contributor W. That's kind of what I thought as well. The doors will be laid up both sides on MDF.

From Contributor K:
Generally speaking, I really do not see a problem with what you are trying to do. Plywood is notoriously not flat but you will be sanding it down and that will help with evening it out. Also, you are using a vacuum bag, so if there is a little wave to the sanded face it will conform your 10 mil veneer to the substrate. The one thing that I probably would rethink is sanding the plywood down to the core. Exposing the core layer might really make the plywood unstable and make it cup or warp. Depending on how long you leave the core exposed before you layup and finish the new face will influence what types of problems you might have. Also, exposing the core could potentially reveal voids or grain that might not be conducive to putting on a new face. If you can just sand off the finish and leave the maple face that might prove to be better. The maple face without the finish should be a much better surface for veneering.

From contributor M:
We do this often without problems. We simply sand one side with 80 grit to scuff the finish and then veneer in a vacuum press. Do not sand through to the core, as stated above.

From contributor J:
You can buy pre-finished maple one side. Another option is to lay up your walnut exterior on 1/4 MDF and then press it to 1/2" pre-finished.