The frame for the vacuum box.
Vacuum box with bottom attached.
Had to do a lil math for the parabolic reflector contour.
Ribs for the parabolic reflectors.
Ribs inserted into the heating element box.
Bending the aluminum sheet for the reflectors. Aluminum has far better reflectivity than steel at infrared wavelengths. Infrared heating elements are the heat source to bring the plastic to its glass transition temperature.
Test fitting the first reflector. The purpose of these is to uniformly distribute the thermal radiation onto the plastic.
Another view of the heater box.
Better view of bending the sheet metal. Who needs a sheet metal bender when ya gots plywood and muscles!
Reflectors fully installed.
Using extra aluminum for heating element brackets.
The brackets are shaped like a rectangular 'J'.
The Brits call it "al-oo-min-ee-um".
Throw in some heating elements and ya got yourself a heater for the winter too!
3/4" electrical conduit used to hold the heater box above the vacuum box. Pardon the messy shop. Next project, "Operation Declusterfication!"
I grabbed a bowl to test plexiglass.
Tests were performed using:
1/8" HDPE (High Density Polyethylene) - turns kinda gooey
1/8" Plexiglass (Acrylic) - tends to bubble and sag excessively
1/16" and 1/8" HIPS (High Impact Polystyrene) - perfect for vacu-forming
1/16" and 1/8" PETG (Transparent Polyethylene) - good for vacu-forming and it's transparent