I am getting ready to build a 60” hexagonal walnut pedestal dining table. The perimeter will be from 5 1/2” walnut. This will require that I laminate a fletch of walnut onto a fairly stable substrate for the center. The fletches will be about 18” wide and 1/8” thick (less than that by the time I have the table sanded flat). I have experimented with laminating but have no real experience with this type of woodworking.
1. What is the most stable substrate for this project? I tried to use what was called cabinet grade hardwood plywood and it warped substantially.
2. What type of glue should I use? I like using the West System epoxy but this may not be the best choice.
3. Is there anyway to cheaply clamp the laminate to the substrate? I know that the best way would be to vacuum bag it but the least expensive vacuum pump costs about $450. I had some air bubbles the way I did it before.
I have not found anything about laminating this large a surface in Fine Woodworking. If you know of an article please let me know.
Replies
If I understand it, you are proposing to laminate 18" wide panels of 1/8" thick walnut. If so, 1/8 thick wood is not going to act like veneer, and you are likely to have trouble when the walnut shrinks or expands, while the substrate does not.
For a substrate, 3/4 cabinet grade plywood should do well, though I like MDF or ULDF. If your past try warped, were you using thinner ply? Did you veneer both sides of the ply?
For glue, it depends on how you are going to apply the veneer. Vacuum presses require a slower set up; hammer veneering is best with hot hide glue. You might try iron-on PVA, but it's tricky to keep large veneers from distorting.
Best to use real veneer. Since you don't have a vacuum press, you might try hammer veneering one 18" wide piece at a time, but an 18x54" piece of veneer is kind of big and unwieldy. It might be difficult to keep adjacent pieces abutted well.
Thank you for your comments. I made a table like this from red oak and commercially available red oak plywood and was not pleased with the match. I have some nicely figured walnut 2”x18” boards that have been air drying for 5 years that I can cut 1/8th” fletches from. I will sand these to a thickness of less than 3/32” next time on a drum sander. Do I really need to laminate both sides? Couldn’t I simply use polyurethane on the second side? By using epoxy, I am not introducing moisture into the plywood. I like the epoxy because of the long open time and spills are easily. I also use it as a filler in any knots or splits. It becomes almost invisible on walnut after applying a finish.
Bolton
3/32" is still too thick. I understand that anything over 1/16" will act more like wood than veneer, but I'm no expert on this, because I always use veneer and avoid thicker laminates.
Epoxy may not introduce moisture into the wood, but it will become a barrier to moisture. It isn't the introduction of moisture, it's the effect on moisture penetration rates that you need to be careful of. Mismatched sides can have differing moisture penetration capabilities, which can lead to warping. Matching the sides (wood + adhesive + finish) will eliminate this risk.
There's nothing "wrong" with using epoxy for your application. You can't use it for hammer veneering because of the long set time, but if you are clamping, it's fine (though more expensive than other choices). I got the impression that you aren't set up for clamping or vacuum pressing, which is why I suggested a try with hammer veneering. But this assume syou are working with veneer, and not laminating thicker flitches.
Recommending the use of "Hide Signatures" option under "My Preferences" since 2005
I believe that 3/32" is OK to use as veneer although it is at the max. limit. I have veneered with this thickness successfully. I use a vacuum press. I would caution you to use a good grade of plywood as your substrate with this thick veneer. MDF will fail under this thickness. You might visit the forum at vacupress.com for some more info. Darryl, the host, has a wealth of knowledge.
What do you mean that MDF will fail at this thickness? I'm curious because I completed a 5-ft diameter table recently. At present, there are no signs of failure.Cadiddlehopper
I veneered using shop sawn mahogany over mdf. This was just shy of 1/8" before dressing the surface, maybe a fat 3/32 after. After about 6 months, both top and bottom veneers shrank thus cupping. There was no "fixing" this condition so before remaking the top I disected some of it. The glue did not fail (as I had expected). The mahogany pulled the mdf apart. I remade the piece using 1/16" comercial veneer.
I am reading this thread and I am hearing things I have never heard before. I guess I better damn well understand what you-all are saying, because I am planning on helping my son make a bar top.
My intention, in order to give an appearance of mass, strength and durability was to resaw some (most likely) oak boards to about 1/8" or better thick and apply it to two sides of MDF. Using resawn oak also allows me to bookmatch the top. I thought that I might glue 2-1/2" MDF panels together to get a 1" thick panel and apply the 1/8" resawn oak to each side. This would give the appearance of a thick counter top without the cost of solid wood and the advantage of bookmatching.
I was open to use a plastic resin glue. If there is concern about stress cracks in the surface of the oak as it dries out, wouldn't yellow glue (which is more flexible and has a tendancy to creep) be a better choice?
First, I haven't used 1/8" wood as a veneer since I've always avoided using wood that thick, given structural risks. You can bookmatch with veneer provided you get successive flitches, which is the way veneer is normally sold. In fact, the book matching will be better because you don't lose wood when resurfacing resawn wood (the veneer knife cuts without waste).
PVA is more prone to creep than some other glues, but glue joints tend to be stronger than wood. I would expect oak would split before the glue bond would break, but since I've never tried what you are proposing, I can't tell you anything from experience.
I still recommend using veneer, or something 1/16" thick or less. You can get thicker veneers from suppliers, but even 1/42" thick veneers, when applied properly, will give as much feeling of mass as thicker veneers.
It's really your choice if you want to resaw wood you have and take some risks, or go the less risky route of thinner veneers. Whichever you choose, good luck and be sure to send pictures!Recommending the use of "Hide Signatures" option under "My Preferences" since 2005
I agree with pondfish; 1/8" thick wood is not veneer in the classic sense. Unless there is something special about the walnut you have chosen, I'd go with factory veneer. 99.9% of my veneer work is done with hammer veneering. Your table is large but hammer veneering would be ideal. The largest piece I've hammer veneered is a sideboard top with is single piece of mahogany veneer 28" x 73". You might have to work on it on the floor for easy access to the entire top. Below is a link on hammer veneering. While the project in the description is very small, the process is the same no matter the size.
For a substrate, I guess I would use baltic birch plywood. Whatever you do to one side of the top you must do to the other. I don't worry about using the same species on both sides, but both sides must be veneered at the same time or it will warp beyond recovery. With hammer veneering, I quickly brush glue on both sides, and roughly hammer both sides down. Go back and work on the face side getting it prefect and then finish with the back side. Working on just the face can quickly introduce a warp that can't be removed.
If you are set on using the 1/8" thick wood, there is an article in March 1985 FWW by Brad Walters and Richard Barsky on using thick veneers. Also, you'll have to make or buy some kind of a press. I've had good luck with cambered cauls made from ash, using threaded rod as the clamping mechanism, but this was for 30" wide material, and it was slow and unwieldily, which is why I switched to hammer veneering. I'm not one to recommend vacuum pressing, but with the size of your project and the thickness of the walnut, it seems the only workable solution.
Rob Millard
http://home.woh.rr.com/federalfurniture/
I will check out the link on hammer veneering. As I said before, this is one of the many aspects of woodworking that I have not had experience with. Not sure that I have that addition of FOO but should be able to get it through their web sight.Thank you for your time.C. Bolton
I've done a bamboo veneer over a cabinte grade plywood. At what width might i experience warpage if I do not veneer the other side?
That is a tough question to answer. It would depend on the thickness of the plywood, the plywood's construction ( number of plys) and the type of glue you are using.
I personally use very little plywood, and I always veneer both sides of a panel if its width is over 8" or so, or if the piece is a top or a similar item that won't be restrained by joinery.
Rob Millard
"Whatever you do to one side of the top you must do to the other."
That is the conventional wisdom Rob, but it wasn't always the case. There was, and still used on rare occasions I believe, a technique where the solid wood groundwork is bent concave by the judicious application of water on one side (wet rags, paper, etc.) and excessive drying on the other until the ebeniste judged the bend just right.
Then the ebeniste would get the veneer onto the convex side and leave it for a while to straighten out. This is a method I've heard of (read) described for creating the veneered leaves of early 19th. century folding card tables and the like.
I've never tried the technique myself, but I've seen a lot of late 18th century and early 19th century furniture veneered on one side only, and quite a few of those panels weren't cabinet parts locked at the corners and other places with joinery, but were table tops many of which weren't well supported by bearers underneath. Some were pretty flat, and some weren't so good.
It must have been difficult for the ebeniste to judge when a purposely bent ground was 'just right,' ha, ha. Slainte.Richard Jones Furniture
I too have read about the method of veneering only one side. For the life of me I can't find the where I read that, but it may have been the book on veneering by Charles H. Hayward. My memory is that the un-veneered side was wetted until the proper curve had been achieved, then the other side was veneered and the panel clamped flat until the glue had cured.
That this was successful is a minor miracle.
I have never seen such a veneered piece in person. I did see a card table that had the tops veneered, but it had bread-board ends, which also flies in the face of conventional wisdom. The card table was in fine shape. I reproduced a small shelf clock that had the door made with bread-board ends. Despite the fact the door was only 1/3 the width of the card table top, the door on the original had nearly torn itself apart. It is odd how some examples with obvious construction problems ( in the modern sense) survive in apparently good condition and others do not.
In the future I'll substitute "must" with should.
Rob Millard
Hayward discusses techniques for veneering solid wood groundwork Rob. One trick he mentions is to use wide panels where, if it's necessary to use narrow planks to make the width up using tangentially sawn timber. All of the strips of wood are arranged with the heart of the tree facing one way-- if the plank is wide enough and flat enough no edge joinery would be needed to make the requisite width of course. Veneer to the heart side and the tendency is for the veneer to pull this side concave. This is resisted by the normal tendency of the growth rings in solid wood groundwork to pull in the opposite direction. The end result should be a fairly flat panel-- well that's the theory.
The other method I've seen discussed is the one I outlined earlier where boards are purposely bent prior to veneering one side only-- the crowned side. Again though it would make sense to utilise the tendency of tangentially cut boards to cup towards the bark side of the tree to resist the cupping effect of a single layer of veneer.
With solid grounds that have to made up to width it makes technical sense to use radially cut (quarter sawn) planks if possible mostly using fairly narrow strips and veneer both sides. Alternatively double veneering can be done with cross veneering on both sides, but this makes a thicker layer of veneer that might be more difficult to disguise at corners. This last technique of course is in effect a way of making what I know as blockboard and what you Americans will know as lumbercore. Slainte.
Richard Jones Furniture
Edited 2/25/2006 6:59 am by SgianDubh
On drawer fronts, where I veneer only one side, I do apply the veneer to the heart side for the reason you noted.
I also make grounds ( substrate) from narrow boards, arranged with their growth rings in a quarter sawn configuration. Until recently I would only crossband wider boards, such as a card table top, or a tall case clock base, but a failure of a clock door will have me cross-banding all veneer work in the future. I had made a somewhat complex inlaid clock door that had its substrate of narrow quarter sawn boards, veneered both sides. I left it leaning against the wall where the base board heat is . One night the heat came on, and my foolishly placed door cracked. While this was an extreme example, and would not happen in a normal setting, it taught me a lesson. I think a cross-banded door would have survived. In the case of the clock door the extra layer of veneer was easy to hide, because of the moldings around its edge.
On the attached card table, I cross-banded the leaves, and then added a narrow strip of mahogany at the back edge and then applied the face veneers; hiding the extra layer.
Rob Millard
http://www.americanfederalperiod.com
You do very nice reproductions Rob. Not my scene as far as the work I want to do, but I like to see other peoples work in that style. Twenty odd years ago I did a lot of veneering by hand as my employer required it-- days and weeks of bloody veneering sometimes with hot sandbags, cauls, tape, veneer hammer and so on. I got pretty fed up of the job.
I don't do much hand veneering nowadays but I do still know my way around a veneer hammer when needed. I like the fact that with hand veneering you can usually go back to it and have another go whereas in a bag press you pretty much get only one shot.
There's another mention of pre-bending grounds by an author in his book on veneering. I'll see if I can locate the author and the book title for you tomorrow. Slainte.Richard Jones Furniture
Richard,
Thanks.
Your furniture is excellent, and I'm envious of your ability to design your own pieces. I'm not drawn to modern furniture, but I too like to see what others make.
I enjoy veneering more than any other aspect of woodworking. In fact someone asked me what my favorite tool was, and I could not decide between the veneer hammer and the LN No. 4 1/2.
Rob Millard
Thanks in return Rob. The book I mentioned is, Veneering, A Foundation Course by Mike Burton, 2000. Sterling Publishing. ISBN, 0-8069-2855-7. He discusses ground or substrate issues in Chapter 4 and has a short paragraph on pre-cupping solid wood grounds to accept a single layer of veneer. He also goes into phenomena such as telegraphing and details good and bad points of using various man-made boards as grounds.
It's a book that introduces the subject of veneers and veneering very well I think. Slainte.Richard Jones Furniture
<All of the strips of wood are arranged with the heart of the tree facing one way-- if the plank is wide enough and flat enough no edge joinery would be needed to make the requisite width of course. Veneer to the heart side and the tendency is for the veneer to pull this side concave. This is resisted by the normal tendency of the growth rings in solid wood groundwork to pull in the opposite direction. The end result should be a fairly flat panel-- well that's the theory.>Richard, my own experience is, like with people, heart to heart works best and that applies to opposite sides of a veneer layup also. The metaphor is for remembering the rule. aloha, mike
bolton, you have a few options other than vaccum but vaccuuming is the best. Hammer veneering will work but be prepared to work hard in that size. A reasonable vacuum pump is available from a refrigerator motor. The copper lines, one blowing and one sucking will do the job albeit slowly. With the right glue you will have enough time for this kind of pump.
As far as adhesives goes, West System works but pay attention to the time it takes as epoxy can go off faster then you may want it to. Plastic resin (Weldwood), the brown powder you mix in water gives plenty of working time but is problematic in wide pieces as the glue can retemper itself as the water is drawn out through the edges causing a weak bond. Unibond 800 is a very good answer for this problem.
I like Finnply for a substrate. 3/4 ply is 13 layers and quite stiff. Make sure you put the same thickness and finish on both sides for stability. Most of all, try out a few samples before you commit to any material or method. aloha, mike
Mike.
Finnply? I have not heard of that one. I will check around locally to see if it is available. It sounds like a good material for this purpose. I had previously checked around for a used refrigerator compressor but was not able to find one. Think I will renew my search. Thought I could remove most of the air with a vacuum sweeper and finish up with such a compressor. Any idea of how much of a vacuum I should try for? I have used the West System as part of a filler for fiberglass aircraft. In thin layers the set time is predictable.Bolton
<Finnply? I have not heard of that one>Finnish birch=Finnply. Dead friges are easy to come by and as long as you have about 10 inches of mercury, which is not lots of pressure, it will work fine. The finnply is stout and usually waterproof glued. The thick veneer will act like wood and the finnply can take it's forces as long as your glue is up to it. I like West System too and use the Extra Slow hardener because the heat of the day in Hawaii can accelerate the set. Use thickeners like Thicksil or Aerosil to make it like mayonaise and then apply an even coat. I also usually put my edges on first and then veneer over the entire piece. That way I can rout a detail in the edge right through the veneer. I love vacuum work but it has a learning curve and I still learn something new every time I do it. Have fun! aloha, mike
Open the drain plug on your compressor, and spend about $10 on plumbing to adapt the intake to a hose barb, and you have a v-pump, unless it is the oilless type.
If you use epoxy, you should thicken it with micro-spheres to consistancy of latex paint.
I use industrial particle-board. It is harder and stiffer than MDF.
I would just buy veneers. Why make it harder than it needs to be?
I would also suggest that you reduce the 5.5" band by about half. That is a long miter joint, and the chances are good that they will crack open when the seasons change except in an atmosphere that perfectly matches that of your shop forever.
I have just completed some experiments to find out just how much balancing is needed for reasonably flat veneer panels. The opening moral is: always run tests and experiments; different veneers, different substrates, and different adhesives react differently. Also, if the substrate is plywood, cut it so the face grain is perpendicular to the veneer grain. You are adding layers to a laminate.
1. Substrate is 1/16" X 8" x 24" Baltic/Finnish/Russian birch plywood from Woodcraft. Face veneer is 1/40" walnut; the pre-packaged stuff from Woodcraft and others. Backer veneer is 1/32" Tineo from Joe Woodworker. Adhesive is Joe Woodworker's Better Bond Cold Press Veneer Adhesive Extra Dark. Out of the vacuum press, it was flat. After two days, the panels (2) had warp and/or twist of at least 1/2" concave towards the Tineo. I think that the thicker Tineo unbalanced the stresses. Good news: less than a pound of weight pushes them flat. Whether I can use them depends on the rest of the structure.
2. Substrate is 3/8" x 10" x 36" Baltic/Finnish/Russian birch plywood from Hogan Hardwoods. Face veneer is 1/32" walnut from Rockler. To start with I veneered only one face with the same adhesive as #1. Out of the vacuum press it was flat. After 24 hours, the single-sided panel had 1/4" warp concave toward the veneer. As I write this, the backer veneer is in the press.
3. On ten other veneer panels made of 1/16" plywood and paper-backed veneer on both sides, I've learned that the number of coats of finish must be the same on both veneer faces.
Moral of the story: As adhesives and finishes cure, they turn from liquid to solid. They shrink as they cure. This shrinkage applies to thickness but also within the plane of the adhesive. This puts tensile stress on that side of the panel. If that stress isn't matched by an equal stress on the opposite side, the panel will likely distort. And the distortion gets worse with time as adhesives and finishes continue to cure (and shrink) long after the time given on the product label.
Let me dispel a few myths I see repeated.
First, 1/8" or so thick solids are fine to veneer with, but the panel must be balanced. Same species, grain direction, thicknessand amount of finish on bottom as on top. Large architectural doors are made by the hundreds everyday with 1/8" solids over corestock, and they have been made this way for well over 100 years.
Second, your solids or veneers - we call them shop veneer around here - will not match in grain when run around the table radially. The beauty of thin veneer is that the grain does not change greatly thru successive sheets, so matching is simplified. Sawn veneer, then sanded will have greater development of grain and will not match.
Third, Urethane glue has a very low moisture content, and is the best for this type of work, with Unibond or similar a close second.
Fourth, You are building what would be a $12,000 commission for my shop. $450.00 is not too much to pay to do it right. This is no time to cheap out. Go all out and spend $1800 on a real pump and bag, and use it the rest of your life.
Fifth, It is possible to do all your laminating on sections of MDF (preferred substrate, period), and then carefully join them together, as opposed to three big flat layers.
Thinking out of the box is fine, but it is hard know which box to go outside of.
Dave S
http://www.acornwoodworks.com
You say that it is OK to use 1/8" veneer over "corestock." Could you please clarify exactly what corestock is? Would you say that the same veneer can be used over other substrates? If not, why not?My experience with the mahogany over mdf certainly has made me leary of doing it again. However if there is a way to safely use 1/8" veneer, I'd like to know it.Thanks.
These have been very interesting discussions. I think most woodworkers would be interested in reading the comments by from all of you. My next question is what is the difference in laminating with wood and laminating with Formica? We never worry about the substrate warping when we laminate Formica on a piece of plywood.Chris Bolton
My experience is that Formica on only one surface will also warp. Perhaps that's why cabinet supply houses sell backer grade laminate as well as surface grade.Countertops ususally well screwed to base cabinets. I left one unscrewed as we were developing our kitchen, and it warped slightly. Years ago I applied formica to one side of a solid core door I was using as a glue-up table, and it has warped slightly in both length and width - perhaps 1/16" in 3'.
Corestock is a general term that applies to the substrate under veneers. Substrate is a synonym. In large doors, some folks use LVL, OSB, MDF, particle board, or solid wood strips or even just a secondary wood, usually of a different species.
If you had pieces of 1/8" Mahogany pulling apart the MDF on both sides of a balanced panel, then either the Mahogany was wet relative to the dry of the MDF when veneered, or the Mahogany was dried after veneering (wet prior to veneering), or the MDF was faulty or sanded below the denser face of the board.
I have long term direct experience in making five ply solids up to 2-1/4" thick (think of hardwood plywood), and using such assemblies in exterior situations in the midwest. At over 36" wide, the face veneers (1/8" thick) will start to crack along grain or joint lines, but only if the panels receive UV radiation for over 3-4 years. One door was 210 degrees on one side, and 68 degrees on the other. Definitely not a balanced situation.
Dave S
I was expecting you to tell me that "corestock" was a term that referred to material that conformed to certain specifications. Instead, it appears that you consider virtually anything to be corestock and thus adequate for 1/8" veneer. Well, that simply does not jive with my experience with the mahogany over mdf. Granted, the mdf may have been faulty (it was not sanded below the surface, nor was the mahogany veneer subjected to any moisture change greater than seasonal variation)..... I did not have it tested. But it's behavior in this case does not seem out of keeping with what others report. It is a commonly held belief that mdf does not hold fasteners well, it tends to pucker up when nails are shot into it, a chisel or plane will shave it sort of like a trowel through wet sand, and the stuff swells like a dead cow in the sun if it gets wet. All these things tell me that it's shear strength is not that of mahogany nor of cured Unibond 800 adhesive. So when the wood veneer wants to move (even a little) it's going to pull the mdf substrate apart. You probably don't agree with all that, but I'm the guy who had to remake the table top for my client. I won't be using mdf under "thick" veneer again unless somebody can give me a compelling reason to the contrary.
I repeated my findings on the various uses of different types of corestock as a sidebar of 35 years working with these types of doors, both contemporary and older - to 100 yrs old or so. My interests are professional, historic and beyond. I myself use solids 99% of the time, and resort to manmade boards in our doors when design demands call for it. We do use MDF as the first choice for large tables, case sides, etc. as a substrate for commercial - thin - veneer and our thicker veneer, and never have had a problem anywhere near what you describe, and we use Unibond 800. MDF has a problem supporting its own weight, but we deal with that by support frames within the work.
Sapwood - I am truly sorry you have had a bad experience with thick veneer and MDF. Remaking a piece is never fun, and does much to undermine one's self confidence. I do not wish to push you in any direction you do not wish to go. I think you should do whatever you want in the future - it's a big ol' world.
I merely described my direct, daily long-term experience as a contrast to one or two pieces of anecdotal evidence. The fact remains that this type of work - thick veneer over MDF or other types of corestock - is done daily, successfully, and has been done that way for many years. I relate this not to specifically compel you to attempt it again, but to add to the larger discussion at hand.
Dave S
Vacume pumps for $450? Check this guy out, he has designed a vacume system that is a fraction of that cost. Course you have to have a compressor...
http://www.joewoodworker.com/
If this equipment isn't suitable, I'd like to know, as I'm planning to put together one of these systems for vacume laminating veneers.
Thanks,
JJ
I love 1/8" veneer and make/use it all the time. Learn to do it right and you will never have a problem with it. aloha, mike
Of course, if you are set on using 1/8" thick veneer, you can veneer to solid wood. Poplar works well and poplar and black walnut have tangential to radial ratios that are close enough that there shouldn't be any problems with differential expansion/contraction rates. What I have done a number of times is veneer to 6" wide poplar boards on both sides. On the side that doesn't show, I usually just use shop made poplar veneer, which seems redundant to veneer poplar to poplar, but it's necessary. The veneers need to be the same thickness. You can use cauls and bar clamps. I then surface one face on the jointer put the other side through the planer, being careful to remove equal amounts of the veneer from both sides. Edge joint the boards and glue up like solid stock. This works very well and for me, seems to be the best way to use thick shop made veneer. I use epoxy for the veneering so as not to have to worry about a water base product warping the veneer, the long open time makes me sweat less, and since epoxy has gap filling abilities, you don't have to clamp the crap out of it.
I agree. One of our pieces of furniture is a very old tall chest with eight drawers. Each drawer has a veneered front about 1/8 inch thick that is sawn from a walnut crotch. All 8 fronts were cut from the same crotch and glued to the drawer fronts in sequential order. All are perfectly still attached after more than 200 years. Obviously the cabinetmaker used hide glue and each piece of crotch is laminated to a solid black walnut board.
Frank
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