Costs are going to depend on what shelving and shelving support material is used, but a good ball-park figure would be around $15 per 4-foot shelf, assuming you're starting empty handed.
This was one of those projects I thought, "Hmmm - I think I should be able to knock those out over a weekend" -aaaaaand I was wrong. I ended up going down a few dead-end roads while coming up with a design and process, wasting several days. I'm hoping that you can benefit from my mistakes ;)
Here's the materials list:
1. Shelving material - in this case: 3/16" x 8" wide tempered glass shelves in a couple of lengths from a local commercial display store. Do not use plate or standard glass - it's nowhere near as strong, and if it breaks it is very dangerous. Tempered glass is anywhere from 5 to 6 times stronger than standard glass, and if it breaks it shatters (completely) into kind of glass "gravel". If you've ever seen a shattered car side-window, you've seen broken tempered glass. Polycarbonate or plexiglass would work, too, but would probably be more expensive and not hold up to use very well (dusting it can scratch it up).
2. Wood stock - I used Purpleheart, Philippine Mahogany, Poplar, and Curly Oak. Stick with hardwoods - softwoods probably wouldn't be strong enough to hold up to any kind of weight. Poplar is considered the softest of the hardwoods and would be as soft as I'd be willing to go.
3. Aluminum angle - I used 1"x1"x1/8" stock purchased at a home improvement store. Make sure to use angle suited to the thickness of your chosen shelf material - i.e. if you use thicker shelving material buy angle with longer "legs" so you have enough to attach to the support.
4. Keyhole hangers - I bought a few at a local store and then more from an online retailer (much cheaper online). Be sure to buy the heavy-duty hangers and also be sure to have your keyhole hangers in your hot little hands before you decide how to machine the slots in the back of the supports. Keyhole hangers vary widely in their overall dimensions depending on brand, so a slot that fits one, might not fit another.
5. Screws - Yes, the hangers come with screws - as does most hardware - and as with most hardware the screws are pretty cheap and weak. I bought better quality screws (#6 and #8 for the hangers and #8 for the "glass clip") as cheap insurance.
4. Finish of your choice - I used a good quality laquer. Since these supports don't get much direct handling, almost any finish would work just fine - paint, rubbing oil, polyurethane, naked, etc. Lacquer dries quickly and is reasonably durable - so it got the nod for this project.
While you really don't need a full shop to build these, it definitely speeds up the process. If you were patient, you could build these with a drill, cross-cut saw, coping saw, hacksaw, and a collection of files, rasps, chisels, and sandpaper.
Step 1: Plans and Stock Preparation
I want to stress that the design of these shelf supports can be adapted and changed pretty easily. The only thing to keep in mind is that the center-line of the anchoring screw (the one coming out of the wall that you'll be hanging these on) should probably be kept above the vertical center-line of the shelf support. You could make these taller, deeper, wider, or whatever depending on your needs and aesthetic preferences.
After thickness planing stock to the same dimension (to keep setup consistent), I ripped the stock to finished width and set up the miter saw for cutting lengths. Unfortunately, the only blade I had on hand was recently used to cut a bunch of laminate flooring when I helped a friend put in a floor - which is about like cutting concrete blocks with the saw - so it was too dull to be very useful. This, however, gave me the opportunity to show a technique for safely cutting lengths on a table saw.
Disclaimer: You'll notice I don't have a blade guard on my table saw - and to be honest I don't know how people work with a saw WITH a blade guard in place - but to do the obligatory C.Y.A. I have to say that you shouldn't use a saw without the guard. Personally, power tools have my deepest respect - respect tinged with fear - so I tend to take very, very few risks. I prefer that my body parts remain attached.
The best way to cut short lengths on a table saw safely is by using a dedicated "sled" - but I lost mine in the last move, so I had to go with the close second: using a spacer board clamped to the fence. The spacer board should not extend any closer to the front edge of the blade than the width of the stock you are cutting, and should be set a bit further away - you want no chance of the workpiece binding between the blade and the spacer board, or, the blade and the fence. Use a push-stick as much as possible and just keep your head about you when using any power tool. Never be reluctant to sacrifice a piece of stock - no body part or injury is worth it.
Step 2: Cut the Hanger Slots
Step 3: Cut the Profile
I marked the two points I wanted connected by the profile, and just drew the curve freehand on one of the blocks. I cut the profile out using a bandsaw, cleaned it up on a drum sander, and then used that finished piece as a pattern to trace the profile onto the other pieces. Keep in mind that you could cut any shape profile you want here, really.
The profile on the remaining pieces were rough-cut to within a little less than 1/16" of the line on the bandsaw, and then cleaned up on the drum sander using an 80-grit drum - and they were all ready to move on to shaping the sides....
Step 4: Shaping the Sides
I wanted a kind of "airplane wing" profile on my supports, so, to get that I had to think about an efficient way of shaping a lot of pieces. In art, they say that any curve can be broken down into a series of straight lines - so I took that to heart and made a jig that would allow me to simply cut the majority of the waste away on the table saw, and then shape the rest on the sander.
While shaping the sides on the sander may sound difficult, if you keep in mind the idea that you are sanding off the "peaks" between straight lines, it becomes a little easier. As I was sanding I'd feel for spots where I could "rock" the piece side-to-side - and I'd focus on those areas. When you can make a smooth, arcing, non-rocking pass over the belt, you should have a smooth curve.
Finally, I went back and sanded all the sides of the blanks down to 220 grit. Man, I hate sanding..... but ya gotta do it.
Step 5: Making the "Glass Clips"
Once cut to size, the blanks were sanded on one outer face and both edges with a 220-grit belt on the sander. This may not be necessary, but it makes them look nice. All edges and corners are then knocked off with a few swipes of a fine-tooth file.
I set up a jig on the drill press to allow drilling the holes quickly and accurately. I highly recommend using cutting oil or WD-40 to lubricate the bit every couple of operations - it will keep chips from sticking to your bit, result in cleaner holes, and keep you from having to stop so often to clear chips or shavings from the drill bit. A small plastic measuring cup with a small amount of lubricant works well - just dip the tip of the drill in every other operation, and it will all go quickly. Lubrication is doubly important for the countersinking operation - you'll get some pretty terrible looking results without it - the aluminum will tend to "smear" more than shear.
After drilling the holes, you'll want to countersink them so that the heads of the screws you plan on using are flush with the face of the angle as shown in the picture. Once again, I used a cutting lubricant (WD-40), but in this case I used a hand-drill as it allowed me to rock the bit a little to get a cleaner hole. I think I need a new countersink bit ;)
Once you've sanded the faces and edges, and drilled and countersunk the holes, you'll want to wash the clips thoroughly. You could use anything that will cut through the oils and lubricants you've used. My preference is Simple Green at full concentration - it does an amazing job of cleaning all kinds of contaminants off of metal, and doesn't leave a residue when it's rinsed off - and it's water soluble and doesn't eat up your hands. Good stuff. Try to avoid touching these pieces with bare hands until after you've applied finish.
Step 6: Mount the Keyhole Hangers
I'm kind of shocked that I don't have any pictures of this, but mounting the hanger hardware to the support should be pretty self-explanatory. You want to make sure that you mount them at the SAME height/position on each shelf support so that their glass-supporting surfaces align when mounted on the wall.
I used a heavier, longer, 1" x #8 screw on the top hole of the hanger since it's the one that will take the brunt of the stress, and a smaller, shorter, 5/8" x #6 screw on the bottom. I used a brand of screw called "Spax" which have a kind of saw-tooth pattern to the threads at the tip which make them easier to install. Pilot holes are a requirement here - don't even think about skipping them as you can either end up splitting the wood, or, snapping the head off of a screw. To make the process infinitely easier, pick up a set of "Vix Bits" - they are amazingly useful for mounting just about every kind of hardware - you'll wonder how you lived without them. Vix Bits (in case you don't know) are self-centering spring-loaded bits that you use in your drill - they will put a pilot hole in pretty much the exact center of a countersunk hole which will ensure that your screw heads end up flush and not canted off to one side or another. One of those tools that's worth every penny.
Step 7: Apply Finish
I sprayed the backs of the shelf supports before mounting the keyhole hangers, but that was probably not necessary - that's up to you to decide. At first, I tried to set up the supports so that I could spray both sides, then move to the top, then move on to the curved side, but that turned out to be a completely 'tarded way of spraying the finish on such small pieces - so I ended up sanding a lot of finish off and rethinking the process. Being as these parts are so small, it's hard to shoot one side at a time without over spraying and getting runs - so the best solution is to be able to shoot the whole part at once - but how to do that?
I found two very viable solutions to this little dilemma. The first was to mount a screw in the end of a board that acts as a "handle" and allows you to manipulate the piece as you spray finish. The screw is adjusted so that it fits in the keyhole hanger snugly so that the piece can be sprayed and held clear of any obstructions while it dries.
The second solution is simpler, but requires some additional stuff - specifically, some small rare-earth magnets (I suppose a board with a bunch of holes drilled in it would work just as well) and long drywall screws. I drilled a shallow pilot hole in the backs of the supports, drove a 3 1/2" drywall screw into the hole and used the screw as a handle while spraying. Then, with the rare-earth magnets pre-stuck to the metal rail on my garage door, I "hung" the supports to dry. This, too, worked very well.
Step 8: Install Glass Clips
Set the clip firmly against the edge of the shelf, then slide the wooden support back to it until it was firmly against and centered on the clip. While holding the parts together, use a Vix Bit to drill a pilot hole (you'll need to make it deeper with a regular bit). I used a #8 x 1" screw to secure the clip to the support. Leave it a little loose to make the next step go a little quicker ;)
Step 9: Shelf Installation
I laid out a rough grid indicating where I thought I'd want supports and used blue painter's tape to get an idea of where they'd be. After making a few adjustments in spacing (moving the tape around), I had a good idea where I wanted the supports, and put pieces of blue tape in the approximate positions. Using the tape allows you to do all your marking of the exact position on the tape, so you're not marking up your wall with pencil lines you'll have to clean off later. I also used a piece of thread stretched between push pins as a layout aid to make sure that all the supports at a particular height were mounted at the same level.
Once positions are marked, I installed screw-in drywall anchors and their anchor screws making sure that the drywall anchors were as flush to the wall as possible. Next, hang the shelf supports (with the glass clips loose) on the anchor screws. Adjust the screws in and out until the support has a snug fit against the wall - but not a tight fit. You want the supports to bottom out on the anchor screw for a nice solid mount. Once the supports are in place, slide the glass shelf into the glass clips (which should be a little loose) and adjust the shelf side to side to the desired position. Next take blue painter's tape and tape the clips to the glass shelf - locking them in position. Lift the shelf with the supports off the wall and flip it outer-edge down. Make sure the clips are fully seated against the back of the shelf and tighten the screw. The clips will snug up against the glass and hold it firmly. Peel the tape off, wipe down the shelf, and hang it back on the wall. You may need a few gentle taps of a rubber mallet to make sure the supports are fully seated on the anchor screws, but most will slide down for a snug fit.
That should be about it! You now have some new super-cool glass shelves :)