You will need these materials:
A road sign, no larger than 24" by 24"
4 #10 x 1" galv. steel machine bolts
8 #10 galv. steel washers
8 #10 galv. steel nuts
4 1/4" x 2-1/2" carriage bolts
8 1/4" galv. steel washers
8 1/4" galv. steel nuts
You will need these tools:
Heavy duty corded drill, preferably with right-angle handle
Jig saw with metal blade
Step 1: Prepare the Signs!
Wash them well with dish soap and a scrub brush to remove any dirt, grit, grime, or tar. Let them dry in the sun.
Step 2: Lay Out
I split my signs in two to get more bowls out of them. So, first divide your sign in two. Second, lay out a rectangle inside the perimeter of your future bowl, offset 2-4 inches from the edges, depending on how high you want the sides of your bowl to be. Mark a slash every inch.
At the corners, mark a diagonal across the corner, then from the center of that diagonal to the corner of your inner rectangle. This will be the slit that allows you to overlap your corners. There will now be two little triangles formed in each corner; mark for a hole at the approximate center of each triangle.
Step 3: Cuttin' and Drillin'
Next, hit all the holes on the interior rectangle with a 3/8" bit. It's a lot of drilling; use a heavy-duty drill, preferably with a right-angle handle, as it has a way of twisting viciously when the bit pokes through the aluminum and gets caught in the metal. Put a piece of wood under your sign to save the bit. Clamp down or stand on the sign.
Drill the corner holes and corner tab bend line holes with the 3/16" bit.
Cut the slits in the corners. Sand any burrs.
Step 4: Foldin'
Put the corner tabs on something like a fencepost and beat them to about 45 degrees. Do the same for the short sides. Everything should come together in a general bowl-like shape. The corner bolt holes should more or less overlap.
Once the corners are secure, thread a nut way down the 1/4" carriage bolt (meaning it has a rounded head, as opposed to a hex head, which can be harsh on the countertop), drop a washer on, and poke it through the corner hole of the bowl. These holes may need a good reaming out because the metal pinches the hole shut when you fold the sides, so hit it with the drill bit if necessary. Drop a washer on from the top side, then apply some thread lock to a nut and thread it just onto the inside end of the bolt. Tighten the bottom nut up, holding the top but with vise-grips or a ratchet and cranking on the bottom nut with a wrench until the legs are super rigid. Repeat for all for feet. See how the bowl sits, and correct any rocking with a hammer.
Step 6: Finishin'!