5. Plastic sheet — ABS or polystyrene are the kinds I’ve
used, but there are others.
That’s it! For the cost of a second-hand toaster oven
and a little hardware, you’ve got yourself the ability to form
plastic stuff. The metal frame shown in Figure 9 is made
from 1/2” aluminum angle (aluminum is much easier to cut
than steel), some small metal brackets to form the corners
of the frame and hold the angles together, a couple of
small hinges, and some nuts and bolts.
You may have to make some modifications to the
toaster oven so that it will accept your frame. For example,
on our setup, we cut out the center of the removable grill
on the toaster oven and fashioned a wood fixture to hold
the plastic sheet and frame so that it was in about the
middle of the toaster (Figure 10). That way, when the
plastic heats up in the toaster oven and starts to sag, it
doesn’t touch the lower heating element.
The vacuum box is just four pieces of wood glued
down to another sheet of wood and then covered with a
piece of MDF on top with lots of holes drilled in it (Figure
11). You also need to cut a large hole on one side that is
just slightly larger than the nozzle on your shop vac.
When the shop vac hose nozzle is pushed into the box
Figure 12. Heated plastic is pulled down over
the mold by a vacuum.
Figure 13. Plastic reflector after forming.
Figure 10. Wood fixture to hold the frame
higher in the toaster oven.
Figure 11. Vacuum box over which the frame
and heated plastic are placed.
56 SERVO 07/08.2018