Veneer seam help please

[Leigh Betsch]

I made some shop cut curly cheery veneers. I’ve matched the edges by using my shooting plane and I am ready to glue them to the substrate. I have tested my techniques when I glued the veneers to the back side. I didn’t fit the backside seams perfect, as they are on the back side and will never be seen and there is some glue bleed through at the seam as expected. But I want to make sure the show side is as good as possible. When I did the back side I experimented with veneer tape and blue painters tape to keep the glue line tight. I didn’t see any difference between the two.
I’m wondering if I could use a bit of thin CA glue in the seams to assure they stay tight? Would the ca glue just screw up the finish? Or have some weird interaction with the veneer glue? I’m using Vak bond 2000 from Quality VAKumm Products.
Any suggestions on assuring a tight seam?

[Steve Demuth]

Since these are shop sawn veneers and you planed the edge, I assume they are relatively thick for veneer - 1/16" or more. Since it's not particularly porous or splintery wood, you should be able to get truly flat and square edges, and if you're using the tape properly, you should get a tight joint. I would, however glue the joint separately, and let it fully set, before the veneer application glue up, to make sure it's tight. I wouldn't use CA glue though - if you use the thin, instant CA glue, it will definitely soak through to the surface of your veneer, and could give you problems in finishing. A little less so if you use a thick gel CA, but still a risk.

It is important to get real pressure from the tape for this to work "perfectly." I do this by applying the tape to one piece of veener first, then carefully attaching to the second piece with the veneer raised a modest angle from flat, so that flattening it squeezes the joint tight. I use regular wood glue (Titebond III usually). There is rarely any squeeze out behind the tape, but if there is, with a thick veneer, a pass or two with a card scraper will remove the glue surface down to bare wood.

[Richard Coers]

CA is a horrible idea. It will wick into the wood and will leave a stain as it soaks into the pores. Traditionally, the seam is glued up before placing on the substrate, but we have no idea of the thickness you are talking about. This link gives you some help. https://sawmillcreek.org/archive/ind.../t-152189.html

[Leigh Betsch]

The veneer is slightly over 1/8” at .140”
I fit the edges a couple of weeks ago but I didn’t get them glued up because I found my glue was too old so I had to wait for more new glue. I got impatient and tried the ca glue this morning. It actually worked pretty well and disappeared with a couple of trips thru the drum sander. But, Either I didn’t fit the glue as well as I thought, or the wood moved. So I think saw them apart and re-fit the glue line.
Thanks for the help.

[Kevin Jenness]

If you use epoxy it will wick up into and bond the joints (assuming they have a sawn or sanded surface). To pre-glue the edges with yellow glue pull them together with blue tape strips and run one long strip along each joint, then flip the assembled sheet over, open up the joint at the bench edge, insert glue with a syringe and fold the joint back together. Take care to get the surfaces flush or run the assembled sheet through a thickness sander before laying up.

Thin veneer can be held together with veneer tape, which shrinks and pulls the joints together as it dries. Thicker veneer is harder to keep together, so I usually pre-glue as above or tape the leaves together with clear packing tape as I do the layup with epoxy.

The glue lines should be tight together when laid up. A little bleedthrough can be expected, especially with epoxy, but there should be no gaps. Bad joints can't be pulled together or filled without showing.

[Richard Coers]

More info on CA staining. https://sawmillcreek.org/showthread.php?147327-CA-glue
Notice a trend? Lots of information passed on here for years!

[Leigh Betsch]

I put a new WW2 in my slider saw and straight line ripped down the seam. Then I taped the leaves together and shot the edge with my Lie Nielsen 51. Edge glued them with titebond II. Then I taped the seam with blue painters tape and sandwiched the veneers between two platens and put them the vac bag. The seam looked pretty good. Then I put vakbond 2000 on the MDF substrate, sandwiched between platens and all is back in the vac bag for a few more hours.

[johnny means]

I straight my edges on the slider or on a table saw sled. I don't touch them with a hand plane, it's not necessary. Any saw marks won't show if the seams nice and straight. Any deviation from straight will show. I use reinforce packing tape to hold my seams tight. It can be pulled really tight and will hold well while being handled. I use blue tape to keep the glue under the veneer and of of the outside face. I glue the seams at the same time I lay the veneer. Run a bead of glue into the seams, roll the glue out and press. I happen to use a vacuum press but, clamps and cauls will work too. Personally, I'll never touch veneer tape again. It's too delicate and the shrinking thing just isn't true.

[Leigh Betsch]

It looks like your process works pretty well.
In the end I ripped it apart on the slider and re-glued the joint after the veneer was glued to the substrate. I had one gap near the end that was bugging me. When I ripped the seam on the slider I put a dial indicator on the cut edge to see if my slider was cutting a true straight line. .002" deviation on a 54"rip cut. I'd say that's good enough. I domino'd the edge and glued the panel back together. I'm calling it done.