veneering question

[Mike Henderson]

All we use is contact adhesive for veneers in commercial unless the prints call for something else....

For furniture that's expected to last a century or so, and for non-backed veneer (also called raw veneer), I would not use contact cement. I'd probably use urea formaldehyde glue.

I've talked with quite a few professional furniture makers who use veneer and all of them have recommended against contact cement for raw (non-backed) veneer for furniture pieces.

I can't comment on commercial furniture or built-ins.

Mike

[jack duren]

We use backed or wood on wood veneers. All veneers purchased have tec specs as guide lines. Follow the guide lines. We usually use FORMWOOD veneers.

[Rick Christopherson]

I'm not trying to tell anyone what to do. It's just that I hate to see anyone risk a problem by not doing something as simple as skinning the back of a veneered panel or something as foolish as using contact cement on "raw" wood veneers.

David, When you say it like that, you are in effect telling people like myself and others that we don't know how to veneer. You don't do $50,000 kitchens or $15,000 tables on a mere wing and a prayer, and hope that they will stay together.

There are a lot of woodworking guidelines that get blindly repeated, but without understanding the basis behind the guideline, it is impossible to know when it is applicable and when it is not applicable. There is no such thing as a single steadfast rule that applies to all situations. Knowing when, is what separates the apprentice from the craftsman.

[Frank Drew]

Correct, I should have said specifically that contact cement isn't recommended for "unbacked, plain wood veneers".

[Peter Quinn]

This is the type of post that draws me to the Creek! Craftsman of vast and diverse experience weighing in on a technical issue somewhat central to the modern craft of wood working and not agreeing. Wonderful discussion here. Better than coffee.

I should preface my comments by noting that I am a mere journeyman and do not have vast practical experience with veneer, just a curious nature regarding its application.

It is my understanding that quality veneer is ALWAYS applied in EVEN numbers, the theory being that equal layers applied to opposing sides of a central core will maintain balance on both sides of that core. A quick look at any good plywood will indicate that veneer core material is always constructed of an ODD number of layers, which in effect equals a central, thin core layer balanced with even layers of veneer on each side. The core material is irrelevant, the force of wood movement must be balanced as best as possible to offer any hope of stability. This technology dates to the ancient Egyptians! Violate these rules and you are courting disaster, or worse, warping.

So by this logic the OP made his first mistake when laminating two pieces of veneer core plywood, as he has violated the balancing rule by not including a central core around which to form his new sandwich. Two pieces of veneer core plywood glued together without the inclusion of a single layer between them in effect creates a panel itself prone to warping. Right or wrong? He should have glued the two panels together with something between them.

Continuing this logic, the only chance he now has of rebalancing the tension in his panel is to veneer only one face of his laminated panel, thus creating an odd total number of layers. How he might calculate the thickness of this final veneer so as to reestablish equilibrium is well beyond me.

Another point reiterated by others is exactly what degree of flatness and stability is required of a free standing wall panel display? Sure, a panel which will be held captive in a frame such as a door which must meet other mill work evenly in a second plane and maintain even reveals has certain requirements for stability. But will a slightly warped decorative wall panel covered in figured veneer offend the eye of most observers, and can you even get close enough to the wall where it will be situated to establish a perspective for evaluating its flaws?

MPQ

[Earl Kelly]

David, I'm with you on this. I've glued up quite a bit of veneer, always raw and commercial cut. I've found the balancing veneer can be a different specie with complete success. The glue and grain direction is the most important factor for me.

Those that are trying to save a few pennies, should be looking for better sources of veneer. I have 1,000's of sqft of veneer that I paid less than $.25 sqft for. And when purchasing figured and exotics, can often find them for less than a $1 sqft. All the veneer co's have "backer" grade veneer.

All those using contact adhesive, congratulations with your success. I have seen a piece of furniture veneered with CC and it is still good today, 30yrs later. But, I've seen more, that were utter failures. Especially down here where the humidity gets in the 80-100% range with regularity.

Earl

[Jesse Cloud]

For what its worth, not an opinion, but some real data... I have had 3/4 baltic birch cup when using water based glue to veneer only one side.

[David DeCristoforo]

"David, When you say it like that, you are in effect telling people like myself and others that we don't know how to veneer...There is no such thing as a single steadfast rule..."

I don't mean to imply that you don't know how to veneer. And you are correct in that, in many situations (but not all) there are no hard and fast rules. But there are basic principals. For the most part, the basic principals are not myth. They are the result of many years of "research" by many different people working under many different conditions. All I'm saying is that it is not "good practice" to veneer only one side of a panel regardless of the thickness of that panel. But I am perfectly happy to acknowledge that there are exceptions to every rule, principal or concept. Let me ask you this... How many times have you bought 3/4" thick plywood that was not (with the exception of face quality) "balanced". Do you think that the manufacturers of sheet goods would continue to "waste" time and material veneering the "bad side" of sheet goods if there was no real reason to do so? I can assure you that, with profit margins in mind, they would not.

[Bob Wingard]

"How many times have you bought 3/4" thick plywood that was not (with the exception of face quality) "balanced". Do you think that the manufacturers of sheet goods would continue to "waste" time and material veneering the "bad side" of sheet goods if there was no real reason to do so? I can assure you that, with profit margins in mind, they would not."


Now c'mon .. let's get real with this. I'm sure a LOT of factors enter into the decision on the part of major manufacturers on how they are going to construct their plywood. One of which may very well be the "balance" you speak of .. BUT .. there is more than one kind of balance. They have the ability to use whatever number and thickness of plies they so choose, why not use an odd number of plies simply for aesthetics ?? Think about it .. how would your cherry or walnut bookcase look if the plywood carcase had grain running lengthwise on the outside, but inside the grain ran sideways ?? Not very appealing, huh ?? Now there's "balance" I could get concerned about.

If you're making a million sheets of plywood per week .. why not use an odd number of plies ?? Can't hurt, and might actually have some benefit .. .. beside, some of those crazy woodworkers might not buy it if they thought it wasn't made "correctly" by their way of thinking.

[Don Inghram]

Ok, here's another thought. How many of you would finish both sides of a project made from plywood. I know I always do. I think the same thing applies to finishing with veneer. Paint just one side of a piece of plywood and set it aside. Will it warp? Bet it does.

[Christof Grohs]

There are a lot of woodworking guidelines that get blindly repeated, but without understanding the basis behind the guideline, it is impossible to know when it is applicable and when it is not applicable. There is no such thing as a single steadfast rule that applies to all situations. Knowing when, is what separates the apprentice from the craftsman.

I suppose there are two ways of looking at this. The OP is, according to your definition, an "apprentice", if not he would not have posted this question. You (Rick) are, according to your definition, a "craftsman". You did not post here asking if you should back your panel. The question was posted by an "apprentice" who does not know "when". We (craftsman) can tell the "apprentice" what we feel is right or what is wrong based on our real life experience but as you said, "there is no such thing as a single steadfast rule..." I think each one of us must come to our own conclusion the hard way as to "when" enough is enough. However, I also think it is our responsibility as "craftsman" to encourage the "apprentice" to error on the safe side and gradually approach that fine line between what works and what does not, such that the "hard way" hurts as little as possible. No one is right or wrong in this thread, just food for thought.

[Rick Christopherson]

The OP is, according to your definition, an "apprentice"......

I wasn't referring to the OP. I was referring to the number of people in this thread that are repeating what they heard or read elsewhere without understanding the concepts behind it.

Always: Finish both sides, Stack and sticker lumber, Alternate grains, cope an inside corner, etc. Never: Make long cross-grain joints, use the rip fence and miter gauge together, climb-cut, etc.

Every single rule mentioned above has a foundation in fact, and every single rule above is no longer applicable in certain situations. Yet every single rule above has been stated and repeated at one time or another as though they were absolutes. The difference between someone that knows the basis for a rule and someone that simply repeats the rule, is that the expert knows when the rule applies and when it doesn't, even if he/she does not point out these facts at the time of the telling of the rule.

[David DeCristoforo]

".... The difference between someone that knows the basis for a rule and someone that simply repeats the rule, is that the expert knows when the rule applies and when it doesn't, even if he/she does not point out these facts at the time of the telling of the rule..."

Well... I guess that let's me out... But, before I go, I would like to ask if that is a rule? And if it is, would there be any exceptions to it?

[Dave Tinley]

Ok, here's another thought. How many of you would finish both sides of a project made from plywood. I know I always do. I think the same thing applies to finishing with veneer. Paint just one side of a piece of plywood and set it aside. Will it warp? Bet it does.

Don-
And how about prefinished plywood?? I use and know of other cabinet makers that like to use prefinished 1/2" plywood for drawers and interiors of cabinets.
Yet every sheet I have gotten has been finished on one side only, and none of them have been warped or cupped. IMHO, the "rule" or statement of fact in regards to applying a finish to both sides applies more so to solid lumber.

[Frank Drew]

j

I was referring to the number of people in this thread that are repeating what they heard or read elsewhere without understanding the concepts behind it.

You're making the same kind of unfounded assumptions about others that bothered you when you thought they were directed at you. And, quite honestly, most of the people I've known who were really expert at something didn't actually refer to themselves as "experts".