Homemade Vacuum Former
While prototyping for Koala Boards, I played around with the idea of a hardshell backpack. My thought was that it would provide a rigid frame on which the skateboard could mount.
While it was ultimately scrapped, this is how I made that shell.
The first thing to do was make a mold for the backpack shape. I figured I could carve it out of wood. Why not, right?
I glued some slabs of wood together and sketched out some guide marks.
Cutting the rough shape with a hacksaw. Fully winging it here. After that I went at it with a belt sander.
The vacuum former itself was made from a thick sheet of MDF. I drilled a hole through the middle and attached a metal flange to the bottom of the sheet.
The vacuum hose was attached to the flange, to suck air through from the top of the sheet.
On the top side of the MDF sheet I placed the wooden mold atop rubber spacers (to allow air to be pulled from underneath). Around the edge of the MDF is a rubber/foam gasket.
The plastic for molding: an ABS sheet held between window-screen frames by binder clips. When my space heater failed to get it to a high, even temperature, I had to stick it in my kitchen oven.
Once hot and drooping, I removed the ABS from the oven and draped it over the wooden mold, pulling the frame down to seal with the gasket. The vacuum sucked out all of the excess air, wrapping the plastic around the mold. You can see a bubble on the plastic where it had overheated, but for a first attempt I was very satisfied.
Trimming the plastic reveals the final form! It came out great. My plan from here was to sew a custom backpack around this skeleton, but in the end I took the design in other directions.
To see how things turned out, check out Koala Boards.