Having problems first time veneering

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bradleyheathhays

bradleyheathhays

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Mar 26, 2021
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Lexington, Ky
I've got this unusual project going on where I'm trying to produce what I'll call veneer wafers. I'm getting raw veneer from mbveneer.com and the goal is to back it with something very thin for support and to have it come out of the clamps perfectly flat, and as thin as possible. Instead of using the pricey stuff I'm first practicing with maple veneer from Woodcraft and using backer from Flagg that I've been told is phenolic, if anyone is familiar with that company; Wilsonart just bought them.

So last night I mate up some .025" backer (pictured below, about 1/3 the thickness of the quarter) with some .020" maple veneer using Unibond800 modified urea resin glue in my newly arrived (!) vacuum bag press. The glue was spread with a 1/16th notched glue spreader, so not too thick but it definitely could've been thinner. After pressing overnight it comes out this morning and immediately curls, and gets more curled with time. The obvious first change in this process to see if I can get the veneer flattened would be to veneer both sides of the backer, which I'll be doing tonight. I got 4" glue roller along with the vacuum bag press so I'll try that out tonight instead of the glue spreader and see what happens. I'd say the glue will go on quite a bit thinner using the roller.

So my question is...what other methods and materials should I look into to produce this ever-elusive veneer wafer I'm after? I don't have any experience using rubber cement but if a form of that could be evenly applied with maybe a spray gun or something I think that might be a process to explore.

I'm all ears.

backer 99.JPG
 
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i think the only solution is to veneer both sides. the type of glue wont matter. When veneering panels they are alway done treated the same on both sides, to avoid this problem.
 
Yes you need to veneer both sides with the grain going in the same direction. I use a 4" foam roller, and apply to both substrate and veneer. There is a general rule you know you have enough glue when after pressing you get a small amount of bleed through like 10-20% more than that and you just have to be a lot more thorough and careful with surface sanding. No bleed though could imply insufficient glue. Also, Unibond is usually plastic for a few days before it gets brittle. What temperature did you use? Unibond 800 has had different recommendations over the years. I just finished a bunch of pressings in a hot garage and I still used an electric blanket to keep everything over 80. This will kick the glue and make it brittle sooner. Keep a small amount of leftover glue in a Ziploc bag laying on the pressing. A small amount, not a lot. I spread it thin in the bag. The leftover tells me when the glue is set and then brittle. Perhaps leave the piece under weight for 2 or 3 days.
 
bradleyheathhays said:
Thanks for the advice everybody. I'm veneering both sides now and I'll leave in the press, heated for 3 days like you suggest Carl.
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You don't need to leave the press heated for 3 days. If you are at 80 degrees, 2 hours max. The telltale sample in the ziploc helps. Then for the next 3 days, you could just leave it flat with a board on top and maybe some weight
 
Here's another thought. Every glue line adds rigidity, when using Unibond. If you made a 3 or 5 ply out of veneer, you would have 2 or 4 glue layers. A few years ago, I made a cover to hide my doorbell. I think I used 10 layers of veneer to make about 1/8" thick. It was curved and I still had some springback, but that is from being curved.
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