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How to Form Homemade Aircraft Canopies

Aircraft canopies -- life-sized or models -- use clear acrylic for canopies molded using the same thermoforming technique. This method is sometimes referred to as vacuum forming, as it uses both heat and vacuum to create the canopy's contour. Making the the canopy itself is not a tremendously large job. Making a quality vacuum box and vacuum frame are the keys to professional quality results.

Things You'll Need

Plywood
Pegboard
Table saw
Glue
Brad nailer
2-by-2-inch lumber
Counter-sink
Drywall screws
Drill
Hole saw
Hardware
Vacuum cleaner
Sheet acrylic
Duct tape
Canopy mold

Instructions

Build the Vacuum Box
- 1
  Cut plywood to construct a plywood box 2 or 3 inches deep and large enough to set your canopy mold on. Glue the edges of the plywood box and assemble with a brad nailer, then allow the glue to dry.
- 2
  Cut a piece of pegboard to place on the top of the box. For large applications, glue 2-by-2-inch supports in the middle of the box so the pegboard sits flat across the top of the box without sagging.
- 3
  Cut a whole in the side of the box with a hole saw the same diameter as your household vacuum cleaner tube.
Build the Vacuum Frame
- 4
  Cut 2-by-2-inch lumber to make two identical frames, both the same dimensions of your box. Miter the edges like a picture frame, then glue them, fastening them with drywall screws or brads depending on the size of your project.
- 5
  Lay the frames one on top of the other. Every six inches, drill a hole through top and bottom frames.
- 6
  Counter-sink the holes on one side with a countersink bit so you can fasten the frames with tapered-head machine screws, leaving a flush surface.
Making the Canopy
- 7
  Place a sheet of acrylic between your two frames. Place tapered-head machine screws through the holes' counter-sunk -- or bottom -- side. Place washers and wing-nuts on the threaded side, tightening them down evenly.
- 8
  Set the canopy mold -- either a store-bought mold or a mold you've made -- in the center of the pegboard on the vacuum box.
- 9
  Insert your vacuum's tube into the vacuum box hole. Create a sealed gasket with duct tape. Turn your vacuum on.
- 10
  Heat the acrylic sheet evenly. You can use multiple hot plates. Make sure you can lower the frame safely over the heat, then turn it so both sides heat evenly. You may have to build a custom acrylic oven.
- 11
  Lower the center of the super-heated acrylic onto the mold, dropping the frame onto the perimeter of the vacuum box. With the vacuum cleaner running, it will create vacuum pressure between the vacuum box and the frame. The acrylic becomes the top of the vacuum box. Because the heated acrylic is the only non-rigid component in the box, the vacuum pressure causes it to form to the mold sitting atop the pegboard.

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