Hi,
Not sure I posted this in the right place earlier so please let me know if anyone here has any ideas.
Please help. I have a cupped roughly 13″ x 13″ veneered 1/4 inch plywood panel I would like to flatten. On one side I have put together a pattern made much the way you might build inlay by cross cutting several different shapes, gluing it into blocks then eventually bandsawed thin (about 1/16 – 1/32) pieces. This “veneer” is made of cherry and maple. I’m not sure of the plywood but it is a good quality plywood and was near perfectly flat when I started. The gluing process is where I may have went wrong. I first glued my home made veneer on one side with white Elmer’s glue, let it dry overnight, unclamped and let it sit out for a day or two before I finally was able to glue the other side. This time with a commercial burl veneer much thinner than mine. After that was out of the clamps for a couple of days it started to warp. I guess this could be due to climate changes instead of poor technique. 😉
My first thought was to try something like a wet towel and an iron on the convex home made side but am afraid it would loosen the glue. I have enough time into this that I would really like to get it as flat as possible. Sanding it down at this point would be difficult to keep it even. The cup is not real bad but just noticeable. It’s meant to be the front cover of a scrap booking album for my wife.
Any advice would be appreciated.
Thank you.
Replies
the problem arose when you glued up one side with veneer, let it dry for a coupla days, and then did the other side.
it needs to be veneered both sides at the same time to ensure flatness.
you could mist it with water, and weight it with heavy weights, making it slightly concave for a day. this might work.
Expert since 10 am.
Your other problem is that you used a thinner veneer on the other side. The veneer that you place on the back side is called a balance veneer. Balance is the key word as it is intended to balance the stress that the other veneer is causing. You should always use a veneer of the same thickness and run the grain in the same direction. If you can, use the same species on both sides. This isn't as critical as other factors, but you should at least try to use a wood with similar properties.
I had much the same thing happen to me, when making the prospect door for a butler's desk, but since I had very little time invested in it, I just made a new one.
I use hide glue for my veneer work, which dries very rigid, but I'm guessing a panel made with white glue would be more flexible. If with fairly light pressure, you can take the cupping out, I'd clamp the panel between sheets of 3/4 plywood or particle board, and put the whole thing in the oven on low ( my oven will hold 170 degrees very accurately, and I use it all the time for veneer work; I leave the door open a crack, if I think 170 is too high). After it has"baked" for a while, take it out and let it cool while still in the clamps. I'm thinking, since white glue is a thermoplastic, the glue line will be softened, and will re-harden when cool. I must say I have not tried this, and it may not work, but it is what I'd do if the panel were mine.
Rob Millard
http://www.americanfederalperiod.com
These are all good tips I'll keep in mind for next time.I haven't heard of the oven idea. I'll give that a try. I can always go back to trying water if that doesn't work.Curious if you would recommend any of the ready mixed liquid hide glue for veneer. This was my first attempt at using veneer but I like what it can add to a piece of furniture and hope to get into it more, maybe try a little marquetry.Thanks everyone for your responses.
You might also try building a frame for the panel--3/4" stock with a groove should be thick enough to pull the panel back to flat--It may not be an ideal solution, but could do the trick.
BTW I have a shop in Annandale and do a lot of veneeed panels for furniture and tables that I make. I typically use titebond 2 and press in both vacuum bags or traditional veneer press clamps.
If you really want to learn about veneer work and marquetry, you should consider taking a class or two from Thomas Schrunk. He teaches at a gallery in Mpls., and is one of the best at what he does--I have learned a lot from him over the years. blueskygalleries.com should get you to a class listing...
Good luckPeter
www.jpswoodworking.com
Before I discovered the virtues of hot hide glue, I used Franklin liquid hide glue, for some veneer work, with great results. I have also used Old Brown Glue.
Rob Millard
http://www.americanfederalperiod.com
The oven idea is worth a try. I think the problem is more the moisture than diferential thickness. All can be avoided, still clamping only one side at a time, by using polyurethane glue, which has no water. You might also have done OK if you did the second side immediately after taking the first side out.
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