Message Thread:
Need advice Crotch Mahogany Conference table
5/23/19
Im finally in over my head. Ive landed a nice contract for a 64" x 144" conference table. Crotch mahogany veneer book matched and running shortway. MDF substrate with tube steel frame beneath and an apron to hide it ( its a Victorian inspired design). I could not source a two ply sheet pre made at that size (any good contacts for future reference would be appreciated). My plan is/was to flatten the veneers, bookmatch / trim, stitch together and finally vacuum veneer press botch sides using ppr resin glue. Ive done ALOT of reading about flattening veneers, crotch mahogany in particular which has opened my eyes to the fact that this is a very difficult veneer especially prone to issues down the road. Hot presses and the like are not an option for me. Here's questions I'm currently contemplating; 1) is a cross band necessary 2) Does MDF alleviate the need for crossbanding ( To me it seems that veneering directly to mdf would be less susceptible to problems than introducing another crossband of wood that wants to expand and contract) 3) if the crossband is necessary can I apply the crossband to both sides of the MDF then proceed with the crotch mahogany and backer? I ask this because I get the impression that the big shops are pressing the two veneers together then pressing to the substrate. I cant tell if there are any negative effects doing it " my way".
Optional info- I have several larger veneer projects under my belt using PPR and pre made paper backed veneers. Ive done some small projects with raw veneers. Past projects have been successful though I have had finishes bite me in the ass on occasion. Im handing the finish over to a true pro on this table but any input on the best material would be appreciated. My finisher typically uses a few coats of sanding sealer and then a cat lacquer or cat varnish. Im sure there are some incredible products out there that can help insure a long lasting product. He and I both felt that this project would warrant 6 coats then be rubbed out by hand .
Thanks in advance for any advice.
5/23/19 #2: Need advice Crotch Mahogany Confere ...
I think you are flirting with disaster by only doing a single ply veneer face. We did a few test panels with crotch mahogany single ply several years ago. It didn’t take long for the faces to check. I’m not sure where you are located, but being in the SE, there are still quite a few facemakers in the area.
5/23/19 #3: Need advice Crotch Mahogany Confere ...
That seems to be the consensus and that is what I will do but Im not sure what the science is behind this approach. Anybody have any thoughts on applying the crossbanding to the substrate then then the face veneer to the crossbanding. To me it seems like six of one half dozen of another. But there's a lot I don't understand here.
5/23/19 #4: Need advice Crotch Mahogany Confere ...
In having a two ply face, the face is stabilized eliminating some of the problems with movement.
5/23/19 #5: Need advice Crotch Mahogany Confere ...
In my simple mind, using a rock hard resin to glue the veneer to a substrate like mdf stabilizes the veneer. If the crotch mahogany cracks in such cases I have to assume the mahogany is shrinking which makes sense to me as the glues moisture leaves. Im still not understanding how the crossband stabilizes better than the mdf. I understand tangential expansion/contraction etc and how crossbanding negates that but it seems with the crotch the tangential direction changes direction like crazy ( maybe my observation is incorrect) and hence the crossband isn't 90 degrees especially in the wilder portions of the grain. At any rate I am going to proceed with the crossband because it sounds like it works. However Im still not sure about the order Im going in and if it has an effect.
5/23/19 #6: Need advice Crotch Mahogany Confere ...
I used urea formaldehyde resin glue on the testing, and it still checked. It sounds like a profitable project if done correctly. With the two ply face, the veneer is softened, pressed and flattened, then then two plied to “lock it down”. I’m playing devil’s advocate to save you problems down the road.
5/24/19 #7: Need advice Crotch Mahogany Confere ...
So, its going to be way easier for me to apply the crossbanding to the substrate than the face veneer. Does that have the same effect or is it somehow different if the two veneers are bonded first? I cant see it being feasible for me to join these veneers full size. That begs the question (if it is necessary) can I crossband each individual veneer then trim trim them to size and bokmatch them?
5/24/19 #8: Need advice Crotch Mahogany Confere ...
It won’t have the same effect as the face being two plied.
5/24/19 #10: Need advice Crotch Mahogany Confere ...
"....can I crossband each individual veneer then trim trim them to size and bokmatch them?"
I do so all the time - especially when I have a burl or something wacky to work with. Even with regular grain face veneers, two-ply pieces are much easier to work with - edging together, matching, taping and pressing.
I think it essential when laying up small parts into larger panels.
5/24/19 #11: Need advice Crotch Mahogany Confere ...
ok! This gives me hope. The veneers are currently 26" x 72" and will be trimmed to 18"x 64. Im hoping I can cross band each piece before trimming then stitch them all into one big sheet.
Anybody out there with conference table/ or larger surface area experience have any wisdom to share? Thanks to both Davids.
5/25/19 #12: Need advice Crotch Mahogany Confere ...
Website: http://cherrybrookwoodworks.com
I have done what david S has done with the two ply. One word of caution though- If you do make a 2 ply they may not always stay flat after the press to make them 2 ply. It makes difficult, thin pieces easier to handle. What I would do is strongly consider subbing the job out.
5/25/19 #13: Need advice Crotch Mahogany Confere ...
Im going to crossband the individual veneers and probably use sizing to give me some extra working time and help keep them flat and manageable. I feel pretty confident in this approach but now I will be pondering the seams. Obviously having the crossband bridging all seams would be best but if it doesn't am I really building in a weak link? I live in Washington state, is anyone aware of a shop that could handle this in the pacific northwest? Im sure there are a couple but regardless I will most likely forge ahead being this far down the road. I will do some test panels and run them through some high and low humidity torture tests to see how they do. The table is going to a very stable climate controlled environment ( what conference table doesn't).
Ive done alot of research/reading on this topic and the internet often leads me to woodweb. Often times the forums are very technical and full of information from multiple contributors. This post seems rather quiet, not sure what I can do to round up more input.
5/25/19 #14: Need advice Crotch Mahogany Confere ...
Website: http://sunvalleywoodworks.com
I can recommend a very good shop in Idaho if you're considering subbing this out. Wood River Veneer in Gooding ID has done many crotch and burl panels for me over the years for dining tables, desks, armoires, doors, ect. The photos show a walnut crotch armoire and an african mahogany crotch vanity I did using their panels.
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5/27/19 #15: Need advice Crotch Mahogany Confere ...
If you have reservations about your results, don't experiment on the final project. See if your veneer supplier can send you some damaged crotch veneer to experiment with. Play with the layup, let it sit around if you have a couple of weeks extra. It's not different than the request for how to darken or lighten a stain/dye on here all the time. Just poor business to experiment on the final project. I had reservations about doing my first big conference table in mahogany veneer with a diamond layout in the center. I didn't think twice about ordering the panels. I used Indiana Architectural Plywood back in the day. Never regretted the decision. Also had them do a 4 way crotch match for a big armoire a year latter. You sure make good time on a project when you do it that way.
5/27/19 #16: Need advice Crotch Mahogany Confere ...
Duster, that's a great looking Armoire. Did you do the legs ? I wouldn't hesitate to lay panels that size up myself. Ric, when you had your table panel laid up was it bigger than 4x10'? that's the problem I ran into . At 64" x 144" it was too big for the companies that responded ( though 60+% didn't even respond to me). As I stated earlier I will be doing several test panels ( I have plenty of veneer) and running various tests on them. Im glad to hear of outfits that do custom layups and hope to find one closer to my neck of the woods. I haven't completely ruled out sub contracting that part.
Cheers
5/27/19 #17: Need advice Crotch Mahogany Confere ...
Don - thanks for the compliment, I've alway thought that armoire was a pretty cool piece. I did not turn those legs. Even though I have a lathe and have done hundreds of table legs, bedposts, ect, the barley twist was out of my wheelhouse. I had those done by Turntech, a shop in Pennsylvania equipped with CNC lathes.
Although I'm usually up for a challenge, I made a business decision and let more experienced and better equipped shops fabricate components for me. That lets me and my crew focus on the things we're good at, which ultimately makes projects like this more profitable.
7/10/19 #18: Need advice Crotch Mahogany Confere ...
Website: http://www.formwood.com
Don,
I know this is probably too late, but you would be better off to have the crotch on a two ply at least in sections if not in the entire size before laminating to a board, or buy it already laminated to mdf. This would simplify your life. I dont think you will be happy with the result if you try and laminate unbacked crotch veneer to a tabletop.
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