I have a customer who wants just open shelves for upper cabinets, no sides or face frames, with really nothing holding them at all but a 1 1/2 rail under the shelves to attach to the wall. These will be 12" shelves. What would be the best way to support them? I was thinking she is going to at least have some sort of support on the ends. I think the longest shelf is going to be maybe 80" long. I was proposing 1 1/2 solid stock (oak) and cutting out the outside corners to fit solid stock, nailed and glued, then installing solid 1x2 frames on outside edge of shelves. Also the square corner stock will be attached to another shelf, which will get nailed to the ceiling and trimmed out. Any ideas? These will be all be made of oak and be stained, so no caulking on these cabinets.
From contributor J:
This sounds like a job for a torsion box shelf. Ian Kirby did a couple of articles on these in magazines like Woodworker's Journal and a long time ago in Fine Woodworking. You might also look into using hardware such as the blind shelf supports that Lee Valley sells.
Once I had a client who wanted these, and wanted 14" deep shelves that could hold a bunch of heavy books. So I made slabs of solid mahogany, 1-1/2" x 13-3/4". I then bored 3/8" or 1/2" holes through the planks, spaced 16" apart, with a long auger bit - so these were 13-3/4" deep holes. Then I lag bolted the sucker to the studs. I countersunk the lag bolts a few inches and got the longest lags I could find, so they went deep into the studs. When installing, it was easy to mark the wall where the lags were to pre-drill through the drywall and into the studs. The other thing I did was, I beveled the back of the shelf a few degrees so that in its resting state, the shelf would be canted slightly upwards. That way when weighted down, it would be level. When the shelves were up, I covered the lags with a 1/4" x 1-1/2" strip of solid mahogany, and then sanded and finished in place. Bear in mind that this is not really an easily removable installation. But those suckers could carry a lot of weight.