Two rules of veneer cladding, which for some reason are silent
My first experience with veneer was in 1997. Then, on occasion, I got a few sheets of oak veneer with a thickness of 0.6 mm.
With this veneer, I pasted over the tabletop for the coffee table. The table top was made of a pine frame on which fiberboard was nailed. It was about 50x40 cm in size.
Then I glued on PVA glue with an iron. There were no problems, everything stuck well, this tabletop served me for several years and during this time no cracks, warping or peeling of the veneer were observed.
Last year I made my own kitchen out of oak and the wall panel I decided to do is also oak.
I used 6 mm plywood as a base. and glued 5 mm thick veneer boards on it.
Speaking of veneer.
Veneer (German. Span - "chips") - wood material, which is thin sheets of wood with a thickness of 0.1 to 10 mm.
According to the method of obtaining, they are distinguished:
- peeled veneer - veneer obtained by peeling on special machines;
- planed veneer - veneer obtained by planing bars;
- sawn veneer - veneer obtained by sawing.
At first everything was fine, but after a few months the veneer began to dry out and the wall panel began to warp and cracks appeared.
I began to figure out why this happened. Plywood is a fairly stable material, and veneer is subject to vibration due to moisture and drying out.
In terms of numbers, on average, for almost any breed, shrinkage will be approximately 0.3 mm. by 100 mm. You can read more about this in the publication below the link.
It would seem that 0.3 mm - three tenths of a millimeter - is very small, but with a width of 600 mm. - this will already be 1.8 mm. That is, cracks of almost 2 mm could appear on my wall panel. What actually happened.
Two rules
The shrinkage of the veneer explained a lot, but apart from that, I thought that there are probably people who have a lot of experience with veneer and it is worth seeing what they advise.
In the videos that I found on YouTube about veneer lining, they paid attention to the type of glue, methods trimming and joining veneer sheets, methods of pressing or rolling veneer, but no one about warpage and cracks said.
I found the answer to the book "Illustrated guide to the production of joinery and furniture products" 1991 edition. Author Shumega S.S.
In the first paragraphs of the chapter on veneering joinery and furniture, I found two rules that explained my mistake to me.
In the first rule it is said that one-sided veneering (as in my case) is possible only for bars, where the width does not exceed double thickness, then the warpage, if any, is very insignificant and imperceptible.
And in the secondrule it is said about double-sided veneering, and that if the parts are pasted on both sides at the same time, this will not cause deformations and warping.
In general, if you look at the amount of shrinkage and these lining rules, then everything becomes clear.
As for the wall panel in my kitchen, I removed all the veneer from the plywood backing and simply glued a 5 mm thick shield from these boards. I screwed it on the wall along one line, which made it possible for this shield to "walk" with a change in humidity. And for more than 8 months, the wall panel has been hanging in the kitchen and no cracks or warpage have been observed.
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Alexander.
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