Thread: Veneer bubbled in finished piece 😢

I had the same problem 3 weeks ago.
I think I did not let the contact glue dry long enough before sanding, and then I think I got a bit vigorous with the sanding and the veneer was left so thin it lost most of it strength and integrity.
I fixed it my using a small syringe from the chemist filled with PVA glue and squirted a bit into the air pockets then greaseproof paper and wood blocks and clamped in place for a day. Can not even see the tiny hole of the needle.
So far it is still nice and flat, I did however have to re sand it a bit then re apply the top coat.
Good luck.

I’m no expert with Titebond Liquid Hide glue but it might be possible to remelt it using a warm iron, then put a heavy weight on top to press the veneer back down and leaving it overnight. For this to work though whatever finish you applied would have to be able to manage with the heat.

Anybody tried melting LHG with an iron before?

Re heating is the way to first try as Chief Tiff said . Id try a hot block first though .
Heat a flat block of hard wood the right size for a bubble + 15mm all round clearance in a microwave for between 1 and 1.5 minutes. Place a sheet of paper then the block and clamp . leave 30 seconds to 1 minute and remove then quickly replace with a cold block . Take it off after a few minutes and check .
To much pressure and you can get a block impression when its hot. Be careful .

Trying it this way gives a good flat result if it works . Good for finished items .

Using an iron is the way if the thing will need other work like re finishing by sanding and polishing . An iron and the back side of a Brad Hammer. A Brad Hammer is like a miniature veneer hammer. It can leave it a bit lumpy though .

If hide glue bubbles like that are not going down for you then an angled slit with a knife and glue placed in and under then blocked down with paper in between works . You can use plastic bag cut up as the paper for easy clean up later too . Glue and normal paper stick and take some getting off.

That veneer looks thin as well . Another good reason for using blocks . What is the veneer in question ? Is it Red Gum ?

For some reason some timbers reglue down in this situation better than others . I used to get a lot of this sort of work . Always either Walnut veneer or Mahogany Veneer . English Victorian furniture. And the Walnut always went back down much easier than the Mahogany . Usually the Mahogany always needed slitting and the Walnut just went back down with an iron with a dab of water on first .

Rob

Edit .
Of course you have to have a microwave in the workshop for the above method . Before I tried a microwave with timber for this I used to heat steel blocks on my electric hot plate . That was OK but the amount of suitable steel blocks I had was limited . Once I started using the Microwave in the kitchen for timber blocks I stuck with it . I now use it for fast curing titebond repairs when its close to the surface like cracks or splits . As well as veneer repairs. I wrap the hot block repair in rags to hold the heat in too.
When I came across a spare microwave I installed it in my work area .

Originally Posted by genericuid

Is there anything I should do differently next time?


Veneer bubble.jpeg

Depends on how your laying veneer . If your laying the red timber veneer first then after its flat and dry your cutting in and pressing the leaves then Hide glue is a good choice as heating and removing the cut area for the leaves is easy. Liquid HG is not as good a glue as Hot HG though . But HHG has to be pressed on with a heated caul or Hammer veneered on. Heating as you go . LHG can probably be spread and pressed . Ive never used it . Ive used plenty of HHG . And Ive read some average reviews about LHG by the Luthier guitar builders who love HG but only go for the very best in materials and techniques. They steer clear of it I think .

If your cutting the leaves in and taping them into the red sheet before its pressed then pressing down as one I wouldn't use HG . No benefit .
Id use either two pack glue or poly glue . You have to have a good press system set and ready to go and know how to spread glue perfectly . To much is as bad as not enough . It doesn't take much practice to get if right . The benefit is a tough glue job that's water resistant and can handle a lot more heat than HG . It wouldn't lift like that in your picture.

If your cousin " He had it in the kitchen near the coffee machine, so I'm guessing moisture?"

Yeah heat and moisture does it fast . Its the way to remove veneer glued with HG fast if that's what your trying to do.

Rob

Thank you guys! I'll start by trying the hot-block method; hopefully without requiring slits. It's scary trying to patch up a finished piece! To tell you the truth I can't remember if the finish was shellac or an oil-based one.

To answer questions: This is red-gum veneer, 0.67mm I believe. The marquetry was done before anything was stuck down; it was all put down at once.

Next time I do this, would simple PVA glue give me a better result? It was my first proper attempt at marquetry and there are so many conflicting articles; some said PVA is a bad idea because it dries rubbery.

Originally Posted by genericuid

Next time I do this, would simple PVA glue give me a better result? It was my first proper attempt at marquetry and there are so many conflicting articles; some said PVA is a bad idea because it dries rubbery.

Rubbery isn't really a problem with veneer laying . Contact glue is extremely rubbery and people like to use it .
Plain old White PVA is good . Less likely to bubble from heat and moisture after its dry but it still happens . Its just that HG comes loose much easier with heat and moisture.
Ive layed with PVA and the only thing I found a problem was getting all the glue on and in the press in time before it started to dry. On a hot day that can be worse . Its the size of the job that plays a part in that . One panel 1M x 2M would be ok if your press and glue technique is good . I did a cabinet and had about 5 shelves to do both sides at once , all stacked up in one pressing . I was going like mad to get it all in and down and almost lost the battle . It worked out great though and came out very good .

PVA is much harder to remove by heating . HG is perfect if that has to be done . If its a job where after the main sheet is pressed you want to go around and cut 1 inch around all sides with a cutting gauge , warm up the 1' with a iron and slide it off to then replace with a cross banded edge of same or some other timber or prepared strips of cross banding and string inlays then HG and HHG is the way to go . The ability to heat and remover gets harder with the passing of time but its always there . Its just real easy over the next few days .

With applying the PVA good and fast . The best way I found , and I don't own a glue applicator roller that has a pot holding glue above a roller. Was spreading glue out with a notched trowel , then using a scrubbing brush , the type with a handle and stiff plastic bristles like you see people on hands and knees scrubbing a floor with . I brushed out the glue even with that . Ive used the same with two pack glue . Techniglue Epoxy.

Another reason to go Epoxy or Poly is they are not water based . Water based like PVA or HG causes other problem like your panel bowing or warping from moisture being used on one side. That's not so bad if your laying sheets both sides at once as I did with my shelves in a stack .

In the old days , Victorian times, The era of sliced veneer laying , 1840 to 1880, you see a lot of good work where they only veneered one side using HG . You do see some things that suffered badly because of this ( Card tables with a top veneered and the under side covered in felt is a common one ) but you also see plenty that didn't suffer . That are still perfect 160 years later. Its not just by chance that a lot lasted well . The guys building back then were so in tune with what they were doing that I think they chose the right side of the ground to lay on and treated it right before pressing or laying . They probably knew the right amount of drying and pre shrinking of one side to compensate for the enlarging that was coming with the wet work they were about to do . Its one of those secrets which that has never been written down, just passed on by word of mouth at the time and stayed in the work places that knew it .

Rob

Personally I think veneer should be applied with a rigid glue line so not titebond or hide glue and not contact cement. Urea resins are good but have risk and are more difficult to get here (Unibond 800 for example).

Polyurethane or epoxy like Techniglue if you have a vacuum/veneer press.

It's a shame because that marquetry looks excellent. I would just remake the panel from scratch personally otherwise you might run it to more troubles down the line once you get it flat again.

You could use it as an opportunity to do some inlay.... Hide the nasty

On gluing veneer, it's epoxy 100% of the time. Zero failures, zero water/moisture hassles and zero movement.

Just wanted to post an update and a thanks: I used the hot-block method and it worked pretty well! Managed to get rid of most of the problem without creating any new problems
Then I put another layer of wax, and things looked not-quite-as-good-as-new-but-sufficient.
Next time, epoxy!