For veneering, I'd do a couple tests on scraps of the plywood to see if contact cement will stick to it. There are water based versions and more toxic classic versions out there. The classic version in my experience is better, but my experience doesn't include any recent contact cement offerings

 

Thanks 4DThinker. Can you suggest a specific adhesive produce you've used in the past for this sort of thing?

 

In the past is the key word. I taught furniture design to college kids for 4+ decades and have now retired. There was an era in the middle of that when we benefitted from free donations of paper backed veneer for our students projects. Flexwood was the brand name. Not once that I recall did the projects require veneering over pre-finish plywood. A google search for "contact cement" finds far more brands selling it than were available those days. I suspect any would work over unfinish plywood or other sheet goods. Weldwood is a good brand to start with. Even Elmers makes some. I've only used contact cement on two of my personal projects. Both with laminate rather than veneer.

 

Welcome to the forum Phillip.

 

Hi Phillip and welcome to the fun. The key thing to me about attaching anything with contact glue is that you have to be very careful not to trap air in it. That, however, applies to pretty flexile laminate. For something thicker, contact cement is still a good choice, however the instant the glued edge of the multi layer (stiff) veneer touches the side wall, there will be no positioning it after, so in that case CA glue may be a better choice because you can position it for a few minutes after gluing. But then you really have to make sure you have some sort of pressure against the veneer's face to have it stay flat.

 

Welcome to the router forum.

 

Hello all,

Many thanks for your replies. I'll post back pictures if I remember to do so!

Phillip (at work)

 

Great, we always like to see pictures of projects.

 

I've use Unibond 800. It is a two part adhesive. Stuff works great, gives excellent bonding and time to adjust if needed. I don't like contact cement, except for laminates.

 

Check the technical data sheet at the plywood manufacturer’s website (or contact them) concerning the finish as adhesives may fail over time depending on the formulation in the finish that is on the prefinished plywood.

I did a set of kitchen cabinets using prefinished maple plywood except for where the cabinet boxes would be exposed. I used unfinished maple plywood for those cabinet sides. I cut those components oversized and clear coated the interior surfaces. Then cut to final size and milled dados, etc. and assembled.

For the plywood product I used (I don’t recall the manufacturer’s name) they recommended the entire finish be sanded off before using any adhesive on it so it was just easier to use unfinished ply in those locations.

 

What product should I use to adhere veneerrs? I suppose some form of contact cement is the way to go. Of course I want the bond to be permanent. I don't have access to a vacuum press.

I have about 30 years of experience in a cabinet shop doing this.
1) Sand off the finish, or at least rough it up thoroughly with something like a 60 grit sanding disk.
2) Without a vacuum press, contact cement is the usual method used. Ideally, you'd want to be able to spray it on, as spraying gives a thicker buildup of adhesive, for a better bond.
If you have to roll it on, I'd recommend at least 2 or 3 coats. Apply each coat, and allow to dry to the touch before re-coating, at least 20-30 minutes.
After the final coat, again, allow to dry to the touch. The drier it feels, the better the bond will be.
3) After applying the veneer, press it thoroughly with a small block of wood, approx. 12-15" long, and 3/4" x 1-1/2". Round all the corners of one end with a 1/8" radius. Use two hand to apply a lot of pressure with the end of the wood, making sure to cover every square inch.

Dry contact cement, and extreme pressure with the wood block are the keys to a permanent bond.