This is my entry for the EMRR's Reusable tip contest. I always wanted to build a vacuum forming machine and the Retro Spaceship Contest was just the motivation I needed. After surfing the internet I found a nice inexpensive design by Ralis Kahn (www.halloweenfear.com/vacuumformintro.html).

My goal was to build a vacuum former for less than $50. I modified this design by eliminating the heating element; I substituted our family oven.

Here is what you need:

• 1 - 13" x 19" Heavy Duty Cookie Sheet
• 1 - 13" x 19.75" x .25 plexi-glass sheet
• 1 - 2.5" PVC 90° Elbow
• 4 - 6" x 1-1/2" Aluminum Angle Iron pieces
• 2 - 11.5" x 11.75" x .75" laminated particle board pcs
• 2 - 19.625" x 11.75" x .75" laminated particle board pcs
• 2 - 5/16" x 8' screen frame material
• 8 - Plastic screen frame corner pieces
• 8 - Large paper clips
• 1 tube silicone caulk

Start by drilling 1/16" hole in one corner of the cookie sheet and continue drilling 1/16" holes 1 inch apart over the entire surface.

Next, drill about 2" hole in the center of the plexi-glass sheet. Then glue the PVC elbow over the center of the hole so that the elbow is pointing out toward one end of the plexi-glass sheet.

Next, assemble the particle board into a box using the aluminum angle iron. Cut a clearance hole or slot in one end of the particle board box for the shop-vac hose.

Now test fit the box, plexi-glass sheet, and cookie sheet. The slot in the box should align with the elbow mounted to the plexi- glass. Mark and drill the mounting holes through cookie sheet and plexi-glass into the box.

Next put a thick bead of silicone caulk on the edge of the cookie sheet then lay the plexi-glass sheet over it making sure the cookie sheet and plexi-glass seal. Mount this assembly to the box.

Finally, assemble the 2 screen frames making them slightly larger than t he cookie sheet.

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Operation is pretty simply. Clamp a piece of plastic (polystyrene, ABS, etc.) (thickness is your choice) between the screen frames using the large paper clips to hold the frames together. This assembly should be heated. I used our oven at 375° for about 2 minutes. With the shop-vac attached to the PVC elbow, turn it on and place the master onto the cookie sheet. After the plastic is heated quickly place it over the master pushing all the way to down until it contacts the cookie sheet. The vacuum will then take over. Once the plastic begins to cool; turn off the vacuum and carefully remove the master.

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