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11-20-2023, 01:08 PM
(This post was last modified: 11-20-2023, 01:26 PM by joe1086.)
My daughter has an alcove in their family foom that's about 12' long and 8' high. I'm building a cabinet/bookcase to fill the space. When completed, it will be have 12' long run of base cabinets. On top of the base cabinets on each side will be 3' wide bookcases, leaving about 6' open area in the center for the TV. I've installed the bsae cabinets and am now working on the bookcases. The cabinets, face frames, and countertops are painted white.
For a bit of contrast they want bookshelves to be maple and finished naturally. There will be three shelves in each bookcase, about 35" x 12" x 1 1/2". We've explored solid maple for the shelves, but due to waste and expense I'm leaning on laminating a couple sheets of 3/4" maple ply to get to the 1 1/2" thickness and band the front edge with solid material. I made a mock-up with some scrap and it looks fine.
Question is on how to laminate the plywood. Contact cement, PVA, or some other kind of adhesive? I have access to a vacuum press that I could fit two or three shelves in at a time. Contact cement is my first choice as it is fairly quick and clamping isn't an issue. Thoughts?
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No to contact cement. Yellow glue is easy to use and you will never have to worry about it letting go over time with a big load of books, etc. on it. If you have a vacuum press, so much the better. I would use TB II because it's more creep resistant than TB III, which will increase the stiffness of the glued unit. And that's another reason not to use contact cement. It has very little creep strength.
John
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Ditto on TB II. Several years ago, I built an 8' long reception desk for our church nursery area. The top was two pieces of 3/4" plywood. The area was recently renovated, and they asked me to "get rid of it". I was shocked at how difficult it was!
"I tried being reasonable..........I didn't like it." Clint Eastwood
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Thanks guys. TBII it will be.
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(11-20-2023, 01:08 PM)joe1086 Wrote: My daughter has an alcove in their family foom that's about 12' long and 8' high. I'm building a cabinet/bookcase to fill the space. When completed, it will be have 12' long run of base cabinets. On top of the base cabinets on each side will be 3' wide bookcases, leaving about 6' open area in the center for the TV. I've installed the bsae cabinets and am now working on the bookcases. The cabinets, face frames, and countertops are painted white.
For a bit of contrast they want bookshelves to be maple and finished naturally. There will be three shelves in each bookcase, about 35" x 12" x 1 1/2". We've explored solid maple for the shelves, but due to waste and expense I'm leaning on laminating a couple sheets of 3/4" maple ply to get to the 1 1/2" thickness and band the front edge with solid material. I made a mock-up with some scrap and it looks fine.
Question is on how to laminate the plywood. Contact cement, PVA, or some other kind of adhesive? I have access to a vacuum press that I could fit two or three shelves in at a time. Contact cement is my first choice as it is fairly quick and clamping isn't an issue. Thoughts?
You may want to consider building torsion box shelves. Nothing could be stronger in bending:
Not that tough to make, that's me standing on the TB shelf I built. I weigh 185 lb. See any bending?
Rip to width. Plane to thickness. Cut to length. Join.
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(11-22-2023, 03:35 PM)Edwin Hackleman Wrote: You may want to consider building torsion box shelves. Nothing could be stronger in bending:
Not that tough to make, that's me standing on the TB shelf I built. I weigh 185 lb. See any bending?
Not many would make dovetailed corners for a torsion box. You the man, Edwin. And, yes, a torsion box is incredibly stiff.
John
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For a less then 3' long shelf - IMO you don't necessarily need a 1-1/2" thick shelf (unless that is the look you are going for). May wish to consider a single sheet of 3/4" furniture grade ply with a wider front edge treatment which should make it stiff enough. Also, no need to edge band the front of the shelf with this construction. If looking for something that thick I like the torsion box idea - stiffer and less weight.
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11-27-2023, 12:20 PM
(This post was last modified: 11-27-2023, 02:10 PM by joe1086.)
Thanks all. I ended up using TBII to laminate the shelves. I pulled out the vinyl vacuum bag I hadn't used in years...and found it was pretty well contaminated with some sort of sticky substance, both inside and out. It's a big bag so hopefully I can clean it. Oh well, clamps it will be for this.
Daughter wanted the look thicker shelves, otherwise I would have done what Don suggested. The laminations are plenty stiff enough and the Sagulator said they won't deflect much at all.
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I know its done...but you were overthinking this. 35" span and 12" wide shelf, even 3/4" plywood would hardly sag. A few scattered drops of TB-II between the layers and a couple of spring clamps to keep them from sliding will be more strength than that ever needs.
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In a former life, I've had 48" x 12" shelves made out of 3/4 MDF but with an 1 1/4" tall strip of actual wood on the front & back. Wasn't loaded down with books, but it didn't sag.
Now if the homeowner is like my wife and wanted to display her grandfather's vintage typewriter on some floating shelves I just installed, well, no honey, we should just leave that 50 pound paperweight over there on the buffet.
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