Darryl Keil Last Activity 2025-02-12 2:48 PM
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Tom Fama

Posts: 2

Joined: 2007-04-04

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Subject : Veneer Thickness - is 1/8" too much?
Posted : 2007-04-04 8:54 AM
Post #33730
I want to veneer bloodwood on 1" birch plywood (A-2). The panel size is 22" x 69". The bloodwood is cut from 4/4 planks into 1/8" thick veneers. The grain direction of the veneer will be parallel to the long dimension of the panel. Both sides of the panel will have bloodwood veneer. I am concerned about using 1/8" thick veneer. Specifically, will 1/8" be stable and what glue is should I use?




 
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Jeff Patrick


Joined: 2004-04-15
Location: Bainbridge Island, WA

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-04 12:53 PM
Post #33732 - In reply to #33730
I've had two bad experiences using 1/8" shop made veneer. One was mahogany and the other ash. Both were laid over mdf not plywood. And both failed. The edges of the veneer pieces curled up and broke the mdf substrate. The glue did not fail. Since you will be using plywood as a substrate this will probably be OK. I reckon the surface of a good quality ply has a higher tensile strength than does mdf. Nevertheless, my experience tells me that there is a considerable desire for the veneer to seperate itself from its substrate and the thicker the veneer the greater is this desire. (Can wood have "desire?" If it were me, I'd get my veneer surfaced to 3/32" which is the number that I've seen as being the magic upper thickness limit.

(Bloodwood...... hmmm, this sounds sexy..... it may have extra desire.)


 
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Tom Fama

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Joined: 2007-04-04

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-04 4:54 PM
Post #33733 - In reply to #33732
Thanks. There seem to be too many unknowns, i.e. thickness, glue, substrate. Further thinking leads me to consider using solid bloodwood planks, avoiding the complexities of veneering. Using planks is actually less expensive and requires less labor. However, issues with wood expansion need to be resolved.


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-04 6:54 PM
Post #33734 - In reply to #33733
Jeff...can you pinpoint why your 1/8" thick veneer failed? Just curious.

Not to be the voice of opposition of here, but I see no physical reason that the thickness alone would have any kind of contribution to failure or success...even if you are laminating 1/4" or thicker.

One could argue that wood that is pretty thick...1/2" or more, could have some spring or cupping when humidity changes, but something as thin as 1/8" just wouldn't have any spring power to cause any problems that I can think of.

Now with a stacked lamination, I understand some spring, simply because you have many different laminations working together (and no center substrate), but when you are talking about a single lamination, such as veneer, you've got me stumped.

I see no reason to hesitate on this one. I say go for it. I've done plenty of resawing of my own veneer, and have never experienced any failure that I can attribute to the thickness.






 
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Jeff Patrick


Joined: 2004-04-15
Location: Bainbridge Island, WA

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-04 8:42 PM
Post #33735 - In reply to #33734
Well Brian, I have to admit that I was surprised also. But, yes, the 1/8" veneer did cup. In both instances, the edges came up from the substrate. When this occurred, the glue bond held but the mdf did not. I made a cross cut section through one of the tables and you can see how the mdf failed. Interestingly, it did not fail on the edges of the table where there was only one veneer edge. Apparently it takes two edges pulling to create enough uplift to make the mdf fail. I believe that a good plywood substrate would resist this, but I'm not willing to take the chance. Having to remake two tables at my expense in enough of woodworking on the wild side for me.


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-05 8:53 AM
Post #33736 - In reply to #33735
Thanks for the response, Jeff.

I'm stumped.

I'm basing my comments on the fact that sure, 1/8" veneer can cup (and quite often does), but you can simply flatten it easily with very little hand pressure. In other words, it just doesn't have any springy power. The glue should hold it flat, and the substrate should not give under the very insignifacant cupping. Not quite the same as a 3/4" board that has cupped, and then try to press it flat with your hand.

Oh well...good discussion in any case.

Thanks. I'll reconsider things.


 
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Gregory Paolini

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Joined: 2005-02-22
Location: Western North Carolina

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-04-08 5:00 PM
Post #33755 - In reply to #33730
In Book two of Tage Frid teaches woodworking, Tage gives the advice to never use a veneer that's thicker than 1/28th of an inch. The drawings that accompany his statment are what really makes sense.

The area of the veneer that is attached to the substrate will not move (assuming that the substrate is unbreakable). but the top of the veneer will continue to try to expand and contract. If you're lucky, you'll end up with somthing that looks like a crazed finish, or cracks in the face of the veneer. More than likley though, you'll end up with the veneer applying too much force/tension on the substrate, and pulling away from it. And while MDF is VERY stable, it doesn't have the highest tinsle strength in the world.


 
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John Van Brussel

Posts: 3

Joined: 2007-07-06
Location: Buffalo, NY

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-07-06 9:40 AM
Post #33930 - In reply to #33730
Moisture content may be to blame. Also how was the veneer cut and did you thickness sand it?


 
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Bruce Berman

Posts: 20

Joined: 2005-06-01
Location: Pittsburgh, Pa., USA

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-07-06 12:22 PM
Post #33932 - In reply to #33730
I think the question here is "At what thickness does a wood board stop being a board and start being veneer." At an 1/8" thickness a glued up 1/8" layer will want to cup and try to expand (or cotract) cross grain on a rigid core. This is not to say that proper gluing and pressing with the right core will not solve the movement but that there are now additional stresses added to the package which will complicate the stability of the final panel. For a door this could be a problem
. Crossgrain stresses are almost nil when using normal thickness veneer. We only have to balance the resistance to movement paralel to the grain of the veneer. I can't find my copy of Frid's book but this might be what he was thinking of.
We have often resawn beautful boards to repeat a pattern but we think of the 1/8' layers as solid wood that we laminate parallel grain to a core solid wood. When we have laminated 1/8" wood on a plywood core we have had about 1/4 of them twist or bend.
Tom, I think you can successfully build the panel you are planing with the plywood core and good laminating adhesive but it may not remain flat. Try a test on something short but full width. Remember that a lot of exotic woods are not as dry as we might like.
.
Bruce Berman
The Miracle Veneer Trimmer


 
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rlpurdom

Posts: 1

Joined: 2007-07-20
Location: Wenatchee, WA

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Subject : RE: Veneer Thickness - is 1/8" too much?
Posted : 2007-07-20 1:29 AM
Post #33961 - In reply to #33932
Interesting discussion. I have been doing quite a bit of 1/8" veneering in furniture making and also in the cabinet work for our house. I have also built a number of exterior and interior doors using 1/8" over laminated substrate (stiles and rails) and plywood (panels). So far, I have not had any performance problems. The exterior doors have remained stable and flat. My 1/8" veneers are usually cherry - the selection in store-bought 1/8" is pretty limited. Oh yes, I do use the Uni-Bond 800 and love it!
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