Gluing and finishing veneer

[Eric Schmitt]

I have 2 questions dealing with the same material but different stages in the process. Right now I'm testing on smaller scrap pieces to hone my technique.

Question 1:
I'm gluing up a veneer top using the titebond and iron on method... Spread titebond on the base and back of the veneer, let it dry to the touch, then iron it on for adhesion. That part worked well in my testing as far as adhesion goes but the heat from the iron seemed to make the veneer shrink. The joint of the veneer was nice and tight when I started but after setting it with the iron I now have about a 1mm uniform gap down the joint (see picture). Is this something that just happens using this method, did I have the iron too hot, should I dampen the veneer a little before ironing, should I not put glue on the back of the veneer? What's the best way to overcome this so I have a nice tight joint line?

Question 2:
When I get to this part I'll be doing a hand rubbed stained burst finish. I want to make the figure pop. I know the best way for regular sized wood is stain black and sand back then stain the color. My concern doing this on veneer is that that black would absorb too much where I couldn't sand it back far enough or even worse sanding through the veneer. What are some pointers with hand rubbing stain on veneer so I can avoid these potential issues?

[David King]

Eric,
Did you first secure the back of the joint with veneer tape?
I would go further and pre-iron both halves to preshrink them and then straighten out the joint.
The titebond will moisten and probably make a mess of everything so tack down the center first so that any shrinkage will pull in from the sides and not pull the center joint apart again.
I have very limited veneer experience so let's hope someone who knows more comes in on this.

[Eric Schmitt]

I did not use actual veneer tape on the joint. The video I watched the guy used regular blue painters tape so I went with that. The veneer did get preshrunk as I had to iron out a couple of waves in it. I did that first, then used strait edges with the veneer clamped in between and sanded the edges of the veneer to make the joint. Dry fitted up, that gave me a nice tight joint. I used blue painters tape to tape everything in place then spread the titebond on it. Spread titebond on the board also and let everthing dry to the touch (about 30min or so). I double checked the joint before bonding it to the board and everything was still lined up and nice and tight. After ironing the veneer down and removing my tape is when the gap appeared.

[David King]

Eric, I'd dump the blue tape in favor of the brown freezer tape aka binding tape. The traditional method of veneering uses perforated paper tape under the joint and then "hammered" hide glue. The perforated veneer tape is very thin almost like parchment paper and very strong. I imagine it could come unstuck if you heat it up though.
When ironing keep pushing the veneer towards the center seam. You shouldn't need the long tape strip down the seam which will completely hide what's happening underneath.

[Eric Schmitt]

So I've been researching my problem of the gap in the seam. Apparently it's a common problem with using the iron on method even with using veneer tape and specialty veneer glues. On the bit I found the fix seems to be to purposely create a small air bubble line in the veneer close to the seam and then use that to push the seams together. I think this is outside of my skill set for working with veneer.

Brainstorming on another solution, the veneers are a bit bigger than my boards which are not glued up yet. I was thinking maybe I could glue/set the veneers on the boards before I join them together, flush cut everything then join my boards with the veneers already on them together. Maybe that would give me a tight seam. What do y'all think?

[David King]

Eric,
I'd think that would be a whole lot easier provided you can get the veneered surfaces glued up perfectly level. Do you have access to a biscuit jointer?

[Eric Schmitt]

Yeah I have a biscuit jointer so I shouldn't have a problem getting everything level. I'll do some more tests over the weekend and see what works best. THanks for your help on this David.

As for my other question about staining, I was playing around with scrap pieces and I think I've gotten it figured out. The figure in the wood shows up pretty well when just using the color stain and no black stain being sanded back. I think I'll go with that.

[Barry Daniels]

I went down this path before. I tried the iron-on technique and could never get it to work satisfactorily due to the issues you are having. So I got a vacuum bag and used urea-formaldehyde glue (Uni-bond 800). This works so much better. No veneer shrinking at all. Very strong panel after glue-up.

[Rodger Knox]

My guess is that the veneer is absorbing water from the glue and expanding some, then shrinking back as it dries.
Have you tried it with HHG? I suspect that would have the same problem, but maybe to a lesser degree.

As for popping the figure, I've never really liked what I got starting with black and sanding back. That seems to darken the light areas more and doesn't really enhance the natural contrast as much as adding an artificial contrast. Vinegar with a little steel wool disolved in it seems to darken the already dark areas more than the lighter, and enhances the natural contrast. It's a very subtle difference, you may or may not like it.

[David King]

I'm thinking HHG will work since that's the way it's been done for the last 500 years.
Edit: Egyptians started using wood veneers 4000 years ago.

[Patrick Hanna]

Eric, I'm glad you launched this topic, because I have been pondering a veneer job myself. I don't have advice, but I do have a related question: Is fish glue a good veneer glue--assuming the veneer could be clamped for the required time? No hijack of the thread intended--just looking for additional feedback myself.
Thanks,
Patrick

[Barry Daniels]

Fish glue would probably work, but in my experience, any water based glue is risking cracks or open seams down the road. Uni-Bond or epoxy do not have this problem.

On my very first guitar, I glued a burl walnut veneer pick guard to the spruce and the veneer cracked before I got to the finish stage. Lesson learned.

[Eric Schmitt]

I went ahead and decided to go with the iron on method, attaching the veneer before joining my boards. I worked on that today so no going back now. The veneer went on pretty well. A few cracks did develop as the veneer shrank when I put the iron to it. Luckily the cracks were on the ends of the boards outside the body shape so no worries there. I did a quick dry fit and the joints look pretty decent. If I get a chance I'll glue everything up tomorrow. Hopefully everything will come out alright. If not I have a few ideas for fixes. One thought was if the joints don't look quite right is to inlay a strip of maple binding or something like that. If worse comes to worse I'll just strip the veneer and start over with a different method, or just not use it at all. I'll keep y'all updated on how things are turning out and try to post some pictures.

[Eric Schmitt]

Unfortunately doing the veneer didn't work out and I removed it. After everything settled out for a few days I noticed some small bubbles in the veneer. They weren't that big but from my test pieces I know that once I dyed it those small bubbles would swell and stick out like a sore thumb. I tried to flatten and push them out but I ended up cracking the veneer. Even though the bonding of the veneer didn't work out too well the joint did line up really well. I don't think I will try working with veneer again until I invest in a vacuum press. I ended up coming across a really nice 1/4" figured maple top so I'm going to go with that.

[Barry Daniels]

Your results are quite normal for that technique. Just so you know, getting started with vacuum veneering does not have to be expensive or difficult. Check out Joe Woodworker dot com.

[Eric Schmitt]

I knew doing things this way I ran the risk air pockets and cracking the veneer so I'm not too upset that it didn't work out right. I haven't done much work with veneer before so to me this was more of a good learning experience. I learned a few things so to me that's what really counts

[Chuck Tweedy]

Great attitude!
But that was some nice veneer. Was it satinwood??

[David King]

My question is why one couldn't "lance" the bubbles and iron them down again?

[Barry Daniels]

I tried that on my headboard project years ago. The reheating did allow some re-adhesion but the second application of heat caused additional shrinkage of the veneer which resulted in additional cracks.

[Eric Schmitt]

That was my experience with reheating the veneer on the test pieces and the actual pieces. The cracking was very minimal with the first adhesion but putting additional heat cracked it a lot more even in places where it was stuck on good. My guess is it has something to do with the veneer expanding with the moisture from the glue, shrinking with the heat, re-expanding when things cool, then shrinking again with more heat. I'm guessing all that expansion and contraction puts too much stress on such a thin piece of wood.

I still have about 5 or 6 full pieces of that veneer to use the next time I attempt working with it. I've been having it for a long time, if I remember correctly it's quilted anigre.