The tailbox is constructed from coroplast, a tough plastic material similar to corogated cardboard. In the Puget Sound area, many political candidate's campaign signs are printed on sheets of 4 mm coroplast. While the candidates are supposed to remove all their signs within a week or so following the election, some signs wind up fallen by the roadside and abandoned. In late November and December, I harvest these abandoned signs and throughout the year I use them in various projects. This tailbox was constructed entirely from the material in one very large  sign left over from the 2002 Jennifer Dunn congressional campaign. In fairness to Ms. Dunn, her workers did a very good job of recovering most of her signs. This large sign was the only one I found from that campaign and I think it had been missed because it had blown over in a high wind.

The tailbox is constructed using the same techniques I've described in previous articles describing how to make bicycle fenders and a handlebar bag from coroplast. Those articles can be found here:

Coroplast Fender Construction

A Coroplast Handlebar Bag

The tailbox is made entirely of coroplast stitched together with nylon zipties. The box is held onto the rear rack of my bicycle with nylon cord that loops through small holes I cut in the bottom of the box. Elasticised nylon cord forms a web to carry extra gear (like a rain jacket) on top of the box. Elastic cord is also used to latch the box tight.

The box is made from three main parts. The top and bottom of the box are roughly teardrop shaped, while the front, sides and back of the box are one continuous strip of coroplast which follows the curved edges of the top and bottom pieces. I used a saucepan cover as a template for the front curve of the box and a straight edge to mark out the basic teardrop shape. The box is aproximately 50 cm long, 23 cm in width at the widest point and 8 cm wide at the tip of the tail. It is 18 cm tall.

I cut both the top and bottom pieces with an excess flange about 3 cm wide. In the curved section of the box, this flange was further cut into smaller tabs. I bent the flanged portion and puched holes in it so I could stitch the long body sheet around it. The bottom and sides are fully stitched with zipties, while the top is stitched at the front.

In addition to the three main pieces, the top of the box has two smaller strips running the length of the edge from the hinge to the back. I also cut two small coroplast disks, each of which rest on two smaller coroplast disks. These disk stacks work like a button and the elastic cord loops over them.

The lid of the box hinges up. I didn't need to make any kind of a hinge, I simply scored the coroplast along a line where I wanted the hinge to be. In this picture you can see some of the things I carry in the tailbox, including my Topeak Morph pump, my bag with tools, tubes and a patch kit. I also carry a pair of rain pants and a thermolite emergency blanket. On the far right of the picture you can see a taillight wich is strapped to yet another small bit of coroplast.

This is a shot of the interior of the empty tailbox. You can see the cord which loops through small holes punched in the bottom of the box. The cord goes through these holes and ties the box to the rear rack. I kept some extra cord in case I ever need to lash anything into the box to keep items from bouncing around or from bouncing out if I overpack the box and cannot close the lid.

Another shot of the interior, showing how the flanged bottom is stitched to the edge. You can also see one of the edge buttons that secures the lid strap.

That's it. If you were looking for a detailed "How To" you're out of luck. But the info here should give you enough information that you can make your own tailbox. If you do build one for yourself, please drop me a note.