Making at 48″ X 72″, honduran mahogany table top with a 1 1/8″ thick, solid rim around it. Table will also have two, 24″ X 48″ leaves. Because of the glued on rim, I won’t be using solid wood for the top. Also don’t want to use mahogany plywood due to the very thin veneer. Had planned on using 3/4″ MDF, with 1/8″ thick, shop sawn veneer glued to both sides. Now, however, I’m not to enthusiastic about all the weight of the MDF. I want the to to be 1″ thick, so I’ll be using a 3/4″ substrate.
Will resaw mahogany planks on the bandsaw, then sand them to uniform thickness on the drum sander.
Two questions…..
1. Would baltic birch plywood stay nice and flat if I glued on my shop made veneer to both sides? I would imagine it would, but have never used it before.
2. Don’t own a veneer press, and would rarely ever use one again if I bought one, so I’m considering using contact cement to adhere the veneer. Have used cement many times in the past with great sucess. Would this work well in this application?
Any advice would be appreciated.
Regards,
John
Replies
My shopmate makes lovely mahogany furniture using MDF with mahogany veneer on both sides. He uses MDF because plywood isn't as uniform in thickness. With careful joinery at the edges he gets great results.
I've never put 1/8th inch shop sawn veneer on top of a substrate, but the concern I'd have is wood movement. Even though it's thin, wouldn't this veneer have expansion properties that were identical to solid lumber? This is one for the experts here. I simply have no clue as to this one.
What my shopmate does for the edges of his work is to glue on solid edging, using biscuits. He's very precise and gets great edges, requiring no additional sanding (which would be a problem for the thin veneer on the top of the MDF). He uses PVA glue for this and it works great.
If you do decide to glue shop sawn veneer to MDF or birch plywood I'd think you could use PVA glue and weigh down the veneer with bags of sand or some such so that you get enough even pressure. But this implies to me that you've already edge glued the 1/8th inch veneer so that you are logically gluing a large, thin sheet to the substrate. That task sounds more daunting to me than simply gluing the thin sheet to the substrate.
John
Expansion of 1/8" veneer isn't a concern, and is done all the time. You can go up to 3/16" without much of a problem, depending on the wood. A recent FWW article recommends exactly this method to create a solid workbench. The author used layers of MDF, then laminated 3/16" maple to the top and bottom.
Regards,
John
Thanks. I've learned something. Do you remember which issue this was in? I'm a subscriber and must have missed this article.
John
Geez, I knew you'd ask that. :) Don't remember which issue, but it wasn't but 5-9 issues ago. The author used about 3/16" shop made maple veneer with a contrasting wood inlaid over the glue joints. Cherry, I think. He probably used a vaccum press to adhere the veneer, which is obviously the best choice for me too. I just don't want to spend $500 on a tool I'd rarely use in the future.
Since it only takes one 4/4 board of mahogany resawed up to laminate one half the table, I may just try it with PVA glue and a couple heavey sheets of MDF on top of it to weight it down while the glue dries. If it doesn't turn out well, I'll spring for the vac press and won't be out much time or money on my attempt.
Regards,
John
Gotta ask ... is your name John Hardy as well? with a handle like "JHARD..." I'm curious.
The question going through my mind is how you'd make sure the various strips of veneer were tight at the glue joints if you simply used a veneer press.
How about this? take two strips and glue them side by side, with the veneer about 3/16ths thick. If you get the two strips to be 12 inches wide you could run them through the planer to get them to 1/8th of an inch with a good, flat glueline. Let's assume your top is 36 inches wide. Make three of these glueups. Then put one of the glueups on the substrate and weigh it down with some MDF with sandbags on top, for weight. Before the glue dries, make sure that the glue squeezeout at the edge where the next piece will be glued is totally cleaned up.
Once this piece has dried sufficiently (say two hours), put the next piece in and use some bar clamps with a caul to ensure that the glue edge is closed completely, and use some MDF pieces and sandbags to get that piece glued down tight. Repeat the process for the third piece. When all have been glued down tight, a little cleanup on the two glued edges, with a scraper and such, should give you a nice result.
I just don't see how the 3 (or 6, or whatever) pieces will be tightly abutted in a veneer press. But I've never used a veneer press so maybe I'm apprehensive for nothing.
John
Name is John Harden, but that was a good guess... :)
My plan is to joint and make parallel, the edges of the 4/4 mahogany before I reseaw it. This will ensure I don't have a problem with edge joining the veneer. I then run them through the drum sander till they are smooth and the same thickness. After that, I edge glue the 8" wide pieces together to make up the 36" X 48" sheet of veneer, then glue it down to the MDF substrate.
PVA is the best choice here, but not having a vac press, I was just going to use a couple pieces of MDF weighted down with stuff to clamp everything together. Masking tape will ensure the veneer doesn't slide around and come off one edge of the substrate.
I may take your advice and make up three pieces of 12" X 48" pieces of veneer, rather than on 36" X 48". My concern is that I don't want the substrate to warp due to the moisture from the glue. I had intended to veneer both sides at the same time to equalize the hydraulic pressure. That's a big glue up though, so I may chicken out and go another way.
Regards,
John
I thought about gluing up the shop-made veneer first, but couldn't figure out how to get the gluelines absolutely flat. If they weren't flat, the veneer wouldn't be laying absolutely flat on the substrate. That's why I suggested the method I did. But it was just thinking out loud, if you know what I mean.
Let us know how all of this turns out. I'm curious but will remember the result and use it when I do this type of work in the future. As I'm sure I will ... :)
John
Aug2002 FWW has an article on using plywood to make laminated top for fine furniure. I used technique to make a 24/96 buffet top -worked well.
Thanks for the tip. I saw that article, but am afraid that the ultra thin veneer of commercial plywood isn't durable enough for a table that (I hope) will be around for generations. By using shop made 1/8" or 3/16" veneer, there should be enough material there to allow future sandings to remove the inevitable gouges or scratches that will occur.
Regards,
John
There's always ultra-lite MDF if the weight is a concern. I haven't used it for a table top, perhaps others may care to comment.
John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Haven't used it either. How light weight is it compared to baltic birch? I was hoping that BB would also hold the table top fasteners better, but having never used it, I don't know how it would react to the moisture from the glue. I don't want the panel to warp on me.
Love that tag line by the way.
Regards,
John
I can't say for sure how it compares to 3/4 BB Ply, but it's a lot lighter than regular MDF. I can handle a full sheet on the saw w/o risking another hernia. I can also handle a 5x5 BB ply sheet by myself. Therfore I'd say on "gut level" they're pretty close. The ULMDF takes confirmat screws in the face well if you drill a pilot hole.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
>>Also don't want to use mahogany plywood due to the very thin veneer.
Have you talked to a hardwood plywood supplier? I believe you can special order thicker veneer. You pay for it but it is better than learning how to veneer on a complicated piece.
Hadn't thought of that. Might give it a try.
Thanks!
John
John,
I've been following this thread to see what others said, and thought I might weigh in. I veneered some drawer fronts (8" x 46") and used veneer clamps, and PVA. How tough can this be, I thought. Well . . .
What happened to me was that there were places where there was no adhesion, just here and there, with the result that at places it sounded hollow. Then I went and got a vacuum system; worked great!
Good luck, but if you do end up with a new tool, how bad can that really be?
Alan
Another way to adhere veneer is a method my shopmate uses. He spreads thinned down PVA glue on both parts, and lets it dry. Then he places the veneer on the substrate and warms it with a hot iron. It works great.
The issue for this one is that the veneer will be very thick, about 1/8th of an inch. I'm not sure the heat will work with veneer that thick. A test could be made to see how well it works.
John
The really funny thing is my wife keeps saying, "just go buy the vac press". I'm the one who worries it'll be a $500 tool I'll never use again.
Maybe I'll just break down and buy the press.
Regards,
John
Maybe if its not too much trouble, you could ask your wife to talk to mine? She could (read, I could) sure use that sort of good training.
I recommend against PVA and mahogany. The tension in mahogany can overpower the glue line resulting in creep at the joint lines and within the field. I suggest you use a precatalyzed PVA and even better, a Urea adhesive.
Vacuum presses for the home pro (serious hobbyist) cost 298.00. As far as additional use, you can also use the pump for a vacuum hold down fixture which would allow you four side clear routing, sanding.
SWMBO is offering more than you need for a tool???? Now that's unusual :-)John Ersing
Veneer Systems
Veneer Process Consultant
Long time lurker
I'd like to back up the last post by John Ersing.
First issue: 1/8" thick veneer can certainly be a problem, depending
on many things. I cut most of my own veneer and in my personal
experience, I would not go with anything thicker than 1/16". You
can put it on at 1/8", but I'd then get it wide-belt sanded down
to 1/16" thickness. I've had 1/8" veneer pop up despite being well
stuck down with titebond, and epoxy (twas wenge glued cross grain
on hard maple).
Second issue: I strongly recommend a balanced top (same thickness and
type of veneer on both sides. I've seen a 1/8" veneer (maple) on a
1" solid birch table top turn the darn thing into a potato chip
(despite being fastened to a table base). And this was with the
maple and birch having parallel grain.
Third issue: I prefer urea-formaldehyde glues because they bond well
to mahogany, and cure very stiff (reduces chance of creep).
Fourth issue: Cutting your own veneer and getting "invisible" glue
lines is a no-brainer. Setup your jointer carefully and use it
to clean up the veneer edges. Use veneer tape when laying it all
up and you'll be fine.
Finally, I don't recommend contact cement for woodworking veneering.
It can soften up when high solvent finishes are applied. It is very
prone to creep. Some applications demand it, but most table tops would
be better served with a different type of adhesive (in my opinion).
John Feng
All your points are dead nuts on. In the shop I was involved with, we had a real veneering wizard. He too would frequently cut his own veneer and never would it be more than 1/16". While he didn't always use the same species on the underside, he always applied an underside veneer.
He built a headboard for a customer who wanted a copy of a Louis XIV bed. It had probably 100 wedges of two different veneers glued onto a slightly curved or convex substrate in a sunburst pattern. The diameter was over 4 feet as I recall. We measured the elevator in the building probably 20 times before quoting, during construction and when it was completed. We charged the designer $75,000 and the customer paid much more. We figured we could do it for $20 -25,000, tripled the price and made it for less than the $20,000. This was back in the mid 1970's.
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