Currently working on a dining table where I intend to join granite ends onto a shelf cut on either end of a 3″ Bubinga slab. Anyone done this before? What sort of problems would you expect? What sort of adhesive would you recommend? The table will be finished with lacquer before the granite ends will be secured in place. I do not want the adhesive to bother the lacquer at the joint. Any suggestions?
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Replies
Steel dowels, epoxy and a prayer.
Come on. It can't be that difficult. The granite is going to set on a shelf which I have routed out of the slab ends. There will be no stress on the joint what so ever. It will simply butt to the surface end of the wood while setting on the shelf, fully supported. The shelf is 2" thick. I need only bond the granite together to the shelf and at the butt joint to the wood.
If they are relatively small, not attached cross grain and fully supported, I'd go with epoxy. Otherwise I would dowel and try to minimize thermal and humidity swings
If you can get it, "Montage Kit" made by Bison in the Netherlands. (http://www.bison.net) Amazing stuff, not to be confused with your garden variety adhesives at HD.
David Ring
http://www.touchwood.co.il/?id=1&lang=e
If it is sitting on the shelf by gravity .Then I would glue it just in the middle with polyurathane adhesive.I would mask the area of adhesive from finish .Securing the middle will allow the wood to move across the width and urathane is not as rigid as epoxy.
If the wood is coated with lacquer, don't glue it at all. Use some small pieces of carpet tape between the slab and lacquered surface. Don't put anything in the vertical joint. Take into consideration that carpet tape is quite thick.
Cadiddlehopper
If the granite piece is going across the grain you will need to have some way of attaching the end that will allow the slab to move with changes in humidity, just as though it was a conventional breadboard end.
John White, Shop Manager, Fine Woodworking Magazine
You might want to attach a photo or a drawing of this attachment. I cannot visualize it at all from your description. On the other hand, if all you need is an adhesive recommendation, then I would think polyurethane glue would be great. I've found it sticks to anything it comes in contact with. (well..... maybe not air)
Thanks for your suggestions. The granite is going to be across the end grain of the table. Tell me more about the carpet tape. How thick is it? Are there different colors available? If I used this I could simply allow the granite to set on the shelf and be simply stuck (so to speak) to the end of the wood with the tape. The other side of the granite would be held in place by gravity. Only problem occurs when someone tries to lift the table ends! If I use an adhesive I would think that it will not be so rigid as to cause problems with the seasonal movement of the wood. The granite guy wants to use silicone, which I am against.
I looked at the "montage kit" adhesive (from Bison), which was recommended a few posts back; but it only seems to be available in Europe. However, there is a polyurethane construction adhesive that has the same use characteristics and applications, and it is commonly available in most home centers in this country: PL Premium Construction Adhesive:http://tinyurl.com/29648bI have used a lot of it over the past few years, and I wouldn't hesitate to use it for the application you mention; it is a ferocious adhesive, and it will stay flexible enough to accommodate the wood movement in your table.I buy it from Home Depot.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Stone kitchen counters are installed with either silicone or polyurethane caulk. Both would work and the silicone would provide some give for wood movement but fitting a tight joint with either will be difficult due to the viscosity of the adhesive.Using tape is just asking for trouble due to the low strength of the bond; the likeliest outcome will be a broken piece of stone when it gets knocked off the ledger.
I obviously need to secure the granite. Otherwise it is sure to hit the floor or be pulled off the ledge. Polyurathane sounds fine. There will be some wood movement and this should allow that.
porsche911
The granite guy is recommending something he does for other installs. We do many counters with granite or other stone inserts, and they are always glued with silicone, though they have a ply backing to support them. The wood needs to be clean and dust free and the stone the same and unpolished on the face being glued.
Thinking out loud, router out the end grain and set a piece of veneer core plywood, or even better, a piece of cement board into the wood. Glue(with silicone) and screw with countersunk screws. Now you can bond the stone to the cement board with stone adhesives ( most are epoxy based )
Another thought. Use joint fastener hardware. (if the underside of the wood is not visible) Drill the granite and attach the pins with epoxy and use the threaded nut section of the joint fastener to pull the granite tight to the wood. This way you use no adhesive at all between the wood and the stone. JL.
I agree with Porsche911. it all really depends on exactly what you're up to. I did a mahogany vanity with a solid slate top, but the slate was all on cementboard attached to a ply substrate. I used regular pre-mixed tile mastic. If this kind of approach isn't feasible (it requires some thickness), since it's across the grain attach it in the middle (say epoxy) as others suggested. You could also route slots in the shelf to allow for movement, and then attach (using epoxy) bolts to the underside of the granite, to attach the shelf from underneath. You could also drill the granite and use the plastic wall inserts to hold screws from the bottom of the shelf, again using slotted screw holes. This should be OK as long as there isn't any stress involved.
caknuts 1
So many different ways, but only one is going to be chosen by the speedy porche911. It will work, I am sure of it.
Whatever it is, I hope he can keep from being caught by Smokey when he is 911ing down the highway. :-) JL
Edited 2/22/2007 9:16 pm ET by jeanlou
The Porsche will do 180 MPH, but will not join wood to stone!
Porche911
Why am I not surprised? :-) JL
The solution of fastening the wood to stone, if you are using adhesives, is to find a method that avoids gluing the stone directly to the wood. By using a third material as a transition, you eliminate the problem of wood movement deteriorating the glue joint. JL
porsche,
"Porsche... will not join wood to stone!"
My neighbor has a porch with wood columns joined to a stone floor, no problems. It just sets there though, won't do 180 mph.
Ray
Might I enquire as to why you are set against silicone?
If it's an issue with the finish getting fouled, as long as you finish the piece beforehand fish-eyes and the like are a non-issue. It really isn't the evil stuff some tout it to be. Silicone is nice and flexible and, frankly sticks like S#!t to a blanket. It's available in many colours (to match the finish) and it's the product of choice for many residential and marine granite installers.Not to bully you, but he's the granite guy. He knows granite. You know wood. Again, not trying to be confrontational, just my $.02Nat
911, I would do similar to what Jeanlou suggests: two stainless threaded rods say1/4inch diameter epoxied into the granite near each end. These go through slots in the wood to allow for wood movement and are fixed with brass nuts which are housed flush with the wood- finger tight is plenty. Easy and demountable if necessary (for re-location etc): granite is easy to drill with masonry drills.
One thing that is important to me is to set the granite with a gap of 1/16 or 1/32 from the wood and fill it with the bonding material, but only 1/8 or so in depth. The shelf is 7/8 below the surface of the table. The granite is 3/4 in thickness and will have a chiseled edge that will match the natural edge of the wood. It will set on a shim so that the surfaces match. I do not want any crown that develops in the wood to fracture the granite. Nor do I want the edge of the granite, which matches the natural wood edge, tight to the wood so that seasonal expansion may fracture the stone. I suppose this could be silicone. I just don't like any silicone to touch wood if at all possible. No finish will ever stick to that area again.
Thought about your suggestion again. Problem occurs when someone who doesn't know better grabs the end and attempts to move the table. The slab weighs about 300 lbs so it won't move much. The granite ends will lift and the bolt slots in the granite may fracture.
Granite guy said no to this. There are fairly clear areas or crystal in the stone I am using. He said the holes will show through to the surface.
Actually I am now no longer understanding what the flap is about viz.,
1) The strips of granite are only 3/4" thick by how wide- 2 inches?
2) The wood top is 3 inches thick
3) The granite is inset flush or slightly below the surface and does not protrude at any edge
So what is the fuss? Nobody is going to unseat it by picking the top up because it is flush-the top is carrying it.(Anyway it will be a bit heavier than a feather).
All it has to do is sit there so why not use a contact adhesive or a silicone glue that is the right colour? (Silicone paranoia is exactly that -silicone paranoia).
If you want to have "gasket" to take up alight movement/ uneveness or to avoid glueing the stone direct to the wood you could consider useing a thin sheet of material such as leather, pvc, or any number of materials- could be a matching colour or contrasting.Philip Marcou
The table is 4' X 10' X 2 3/4 in thickness and is cut through the entire tree with the natural edge remaining. The edge tapers inward at about 60 degrees. I have cut a shelf on the ends which is 7/8 in depth and 5" in length. The granite is 7" X 48" X 3/4 in thickness. There are edges built into the granite which are 2 3/4 in thickness and are chiseled to match the natural edge of the wood ie tapered inward at 60 degrees with a rough chipped surface which is then sandblasted to remove the sharpness from the chipping. The result is a granite edge that matched the wood edge perfectly. Spendy item, I might add.
A retail hardwood supplier in my area has recently had 2 slabs of Bubinga go through the store, both about 3" thick by 4' wide by some 20 or 24' long. Stunning pieces of wood, but very spendy at $4000 plus.Post a picture when you're done, I'd really like to see your table.
I purchased the piece in 1999 for $1700. It was 3" X48" X 17'. It has about 2" of sapwood which is white with wavy black figure. The heartwood is deep red with wavy brown figure. Stunning piece of wood. Virtually unavailable now. They claimed it was cut in 1985. Can you imaging that tree?
911, if it is as Sapwood has drawn then I had the wrong picture in my mind: shows how a picture is worth a thousand words.
So now the problem appears to be how to attach it in such a way that the wood can move , and so that the granite will not be under strain if the ends are picked up. mmmmmmmm.Philip Marcou
I would do so but the table is at the granite shop having templates made from which the stone will be matched.
Why have you chosen to add the granite to the ends of this slab? How will the granite perfectly match the wood edge while seasonal change makes the slab expand/contract?
This latest description has made what you are doing more clear to me. Here is a drawing of a possible attachment solution, if it's not too late.
The shelf I have cut on the ends of the table are exactly as you have drawn except that there is only 2" of granite overhang the wood. There is 5" of granite supported by the wood. the only portion of the granite not supported by the wood is that 2" part required for the tapered, chiseled edge.
I forgot to mention. I have measured the seasonal change in width of this slab already. Its fairly small and insignificant in terms of the match of granite to wood along the edge. Yes, there will be some stepoff at times, but its very small and not noticeable, given the taper inward away from the edge.
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