Veneering Question

Re: Veneering Question

Bill Tindall, E.Tn.

I urge you to consider Baltic Birch, or its equivalent, plywood for the substrate.

You can use any glue for this application. I use white glue because that is what was used in the Headley shop where I learned to veneer stuff. But I would use yellow if I didn't have white. Or what you are using is fine.

What is critical is to get a layer of glue everywhere, but not puddles. I keep a short stiff bristled paint brush for spreading but one of the 4" fine nap paint rollers is a good choice too. If you coat the veneer with glue it will curl. You will need to tape it down to the substrate so it does not skid as the clamps are applied. What makes the most sense is to coat the substrate, but it is not uncommon to coat both for insurance there is tacky glue everywhere.

Work quick to get the glue spread and the veneer applied. If the glue surface begins to dry before assembly it will not bond well.

Upon applying the veneer wrap the less tacky painter tape around all the edges to hold the veneer in place. I precut these short tape lengths and temporarily stick the ends on something where they are quickly available for wraping the edges. About 3 pieces per edge would be about right for your job.

When it comes time to remove tape pull it off perpendicular to the grain. If you pull it off parallel it may tear the grain.

Couple things...

Ellis Walentine

Particle board is fine for veneered tops, though a bit heavy and more susceptible to moisture damage than plywood.

I have not used cold press glue, but it sounds like just slightly thickened PVA, and I'm sure it will work fine.

Cauls are important, and you need to be sure they are well waxed or that you use wax paper between the cauls and veneers to keep any bleed-through from sticking your cauls to the workpiece.

The important thing is uniform clamping pressure. For a project like this, that will probably mean using crowned beams, and enough of them to spread the clamping pressure evenly. I'd suggest using a double thickness of cauls, too.

Don't forget to balance the construction with a backing veneer on the other side of your panel.

Ellis

Re: Veneering Question

Dick Coers

I'm not a fan of paper backed veneer nor particleboard substrate. Paper backed has a layer of adhesive between the veneer and paper that can be susceptible to hot solvents used in some clear finishes. If you insist on using the paper backed, dust on the first coats of clear to build a barrier limiting the amount of solvent that can soak through. Professional and commercial veneer layups never use paper backed because of this problem. 2 ply veneer is a far superior product if you don't want to work with raw veneer. I don't like particleboard as it makes a good glue seam for the edge banding quite difficult. Particleboard is very course on the edges and you are basically getting a glue bond with tiny chips of wood and gaps. Not much glue area. Depends on particleboard quality and brand of course. I learned to veneer from watching videos and attending seminars, as well as visiting with Darryl Keil of Vacuuming Pressing Systems. In his seminars he demonstrates the heat flexibility of PVA glue. He brings out a dried strip of PVA and places it inside a heating pad. Minutes latter he brings it out and it droops like a noodle over his hand. He never recommends a flexible adhesive on a table surface, as any accent table can be placed under a south facing window. The sun can produce enough heat to soften PVA and allow veneer joint creep. That is with raw veneer, I have no experience with paper backed with that situation. Sorry to reply with negativity, but it's always better to ask for advice before starting.

Re: Couple things...

Bill Tindall, E.Tn.

I have not found it necessary to use a backing veneer with using 3/4 " Baltic Birch on a table top. It already has a multitude of layers and adding one more is not a source of significant cupping.

Re: Veneering Question

Don Stephan

In the past I have used a lot of raw veneer with good results, but have no experience with paper backed. In terms of adhesives, my strong preference is a rigid adhesive as recommended by Darryl Keil, plastic resin glue. If strong screw holding capability is not needed, I most often used good quality MDF for the core; when screw holding capability was needed I used baltic birch plywood, And again following the recommendation of Darryl Keil I always would veneer both sides of the core, if not simultaneously then within a few hours. When clamping, try to insure that the core will remain perfectly flat and straight while the adhesive cures.

Re: Veneering Question

Jesse Cloud

Lots of good advice above. I have gone through a couple of bottles of cold press but wasn't impressed, seems to have a slightly longer working time, but not much.

Only reason I can think of to use particle board is to save money. But you are probably spending a lot more money on the veneer, so its a false economy. Go for some good MDF or Baltic. Beware ply that has those football shaped fillers for voids, they can show through veneer.

If you haven't done much veneering, I highly recommend a trial run with some scrap, just to get the feel for the process and maybe raise some more questions for us.

Re: Veneering Question

Ken Krawford

Thanks everyone for your thoughtful responses. The decision to veneer the top was a last minute thing due to some design changes.

Dick, you mentioned the drawbacks of PVA glue but not your preference.

I thought I remembered particle board being a suitable veneer substrate but it's obvious from the comments that it's not. Easy to change.

Thanks again for your feedback.

Re: Veneering Question

Barry Irby

Lots of good advice already and I second most of it.

Bill mentioned using 3/4" BB plywood and I agree, however, I have a couple of panels made with home made veneer on one side of 1/4" BB plywood and they warp and change with the weather. I could probably figure out how to make a Humidistat out of it. I have read that its the glue on the back side that makes the difference, so you could just coat the backside with glue to "balance" the construction. Never tried it. I am about 99% sure Bill is correct about 3/4" but I don't know enough to comment on thinner, say 1/2".

Nix the particle board. It's crap. Built dozens of kitchen counter tops out of it with plastic laminate. Also replaced about as many that failed. And that was the "Good Stuff", built for the purpose. Use BB plywood or MDF. I hear there is a water proof MDF, might try to find that. MDF can be "tender" and very subject to edge damage and is often sold in sheets that are 49 by 97 to allow for ripping clean edges. As you can tell, I am not a fan.

Just built a laminated arch out of ten layers of white oak about a 1/10" thick each. Used Titebond III because I had it. The layers cupped and warped from the water in the glue. Ended up with 37 clamps on it and it still was not enough. Use a glue that has less water or at least less wetting of the veneer before it goes into the press.

PVA glue

Bill Tindall, E.Tn.

The Headley shop in Winchester VA, a shop that is in the 4th generation of building Period Furniture, uses white glue for veneer. Their pieces sell for thousands. They have done furniture for the white House, and a few presidents. If there is a short coming of PVA glue they have failed to see it. Shown is Jeff "violating" two claims, don't put glue on the veneer and veneer must be flattened before application. (If you have the experience you can violate rules that others rely on)



Shown is Jeff applying glue to veneer with his favorite paint brush. The shop does so much veneering that this brush and jug of glue sits at the ready. And the result:

not too shabby!

Re: Veneering Question *LINK*

Dick Coers

Ken, I will use PVA on small box work but won't on large flat table tops. I use Unibond 800. Attached is an excellent video that shows the instructions I was taught 25 years ago.


https://youtu.be/5lFoUAKkYWU

Re: PVA glue

Don Stephan

Perhaps experience is key to the Headley shop using white glue on buckled veneer. And water and glue are two of the three ingredients in a common veneer flattening solution formula. But I will stick (no pun intended) with flattening solution and pressing for buckled veneer plastic resin for glue.

A bit more info

Ellis Walentine

I didn't mean to endorse flakeboard as a first-choice substrate, but it is at least a credible option. In another life when I had a second job as a product manager at a contract furniture company (three factories, 300 employees), we went through *truckloads* of 5 x 12 sheets of flakeboard every week for veneered worksurfaces, drawer fronts, cabinet sides, etc., all stuck down with PVA glue in a giant cold press. Veneer edgebanding was applied with a big Manea tractor-feed edgebander (hot melt adhesives) without failures or incident. Higher-end options included solid hardwood edging instead of veneer. Flakeboard stays flat better than plywood but it weighs a lot more, which may or may not be an issue. It is also unforgiving of water damage, so don't leave it out in the rain. Personally, I use MDF for veneering and I never use veneer edgebanding or hot melt glue.

Regarding paper-backed veneer, I never use it because it is so thin. I'm not even happy with standard veneer thickness nowadays (typically 1/40"), but there aren't as many choices as there once were. Back when I was doing a lot of fancier veneer work back in the 70s and 80s, standard veneers were 1/28" thick, which left you with plenty of wood to (gently) sand. We used 1/16" veneers for some projects and re-sawed our own 1/10" veneers from solid planks for some really top shelf jobs. Badly warped or deformed veneers, especially crotches and many burls, were flattened with a glycerine and water solution and pressed between sheets of newsprint to flatten them prior to glue up.

Ellis

Regarding backing, it may or may not be safe to veneer one side only; personally, I never do. It is an ironclad rule that I don't want to worry about. If you don't want to spend money for a face-quality veneer (who does?), use a secondary wood veneer or a kraft backer sheet instead.