Introduction: Road Sign Bowl

About: Furniture hacker. Author of Guerilla Furniture Design, out now. Find me on Twitter and Instagram @objectguerilla.

Origami, the ancient Japanese art of paper folding, has some basic principles that have been applied to everything from textile design to lamp construction.  I used them here to fold some old road signs into fruit bowls that combine the angular modernity of architecture with the vintage warmth of antique materials.  The basic idea is very simple, though a little time consuming, what with all the hole drilling . . .  So, if you want to save yourself some time and support your lowly 'structable-er, you can buy the bowls I made for this Instructable in my Etsy shop here:  You can also see another bowl made with a similar method here: That one is a little simpler, as it uses much thinner metal that is easier to bend.

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
Thread lock
Spray lacquer
Dish soap

You will need these tools:

Heavy duty corded drill, preferably with right-angle handle
Jig saw with metal blade
3/8" bit
3/16" bit
Metal punch
Rubber mallet
Scrub brush

Step 1: Prepare the Signs!

Find some old road signs.  I got mine from the state highway yard just by asking.  There are a lot of old signs that are too worn to be put safely by the side of the road, and the highway department takes them down and stockpiles them.  The aluminum isn't worth very much, and the reflective coating on the signs is difficult and expensive to remove, making the process of recycling them conventionally too cost-ineffective to be practical.  Other places to look might be junkyards, antique shops, flea markets, yard sales, and frat houses -- the usual suspects.

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

The holes in the signs weaken the aluminum (a very tough metal) sufficiently to bend it.  To lay them out, determine how big you want your bowl to be and how high you want the sides to be.

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'

Once you have your layout, get to cutting!  Cut the sign in half first, using a jigsaw with a metal blade in it.  The aluminum is soft, and has a way of clogging the blades, so a coarser-toothed metal blade is better.  Then cut the corners off.  Knock down the sharp corners with 100 grit sandpaper.

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'

To fold the bowl, lay it face down on an edge, like a step, with the line of holes on the edge.  Lay down a towel to protect the surface of the sign.  Stand on the sign.  Hit the metal with a mallet until it bends nearly 90 degrees.  Repeat for the other long side.

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.

Step 5:

To get the bowl to hold its shape, pop those machine bolts into the corner holes.  It may take some wrestling, or, in extreme cases, hole enlargening if there is extreme misalignment, but stick with it.  Remember if the holes are way off and you have to re-drill some that the washer will cover up a lot of mistake if you need it to.

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'!

Run a rounded file over the bottoms of the holes to take off any burrs.  Wash thoroughly with hot water and dish soap.  Hit the top side with some spray lacquer to protect the surface and food-proof the sign.