This is another in my Get Smart props series, which also includes two different real working shoe phones (instructable 1 and instructable 2) and a phone booth.
As part of a church camp drama, I decided to make a cone of silence, a shoe phone and a phone box for dropping through the bottom of.
You can read about how I made the cone of silence here.
(Unfortunately the cone got damaged in transit before I took the photos. So these photos - except for the photo of the real cone from the show - are actually of a damaged cone being repaired, but I think you will get the idea, anyway).
Step 1: Find all the bits you need
1. 2x 1.2x2.4m rolls of PETG plastic sheet. I got mine from Menzels Plastics for about $30 a roll.
2. A push pin or similar, for making nice round holes in the PETG plastic
3. A pair of scissors, a ruler and a marker.
4. A packet of 100 teeny tiny split pins for joining the whole thing together.
5. A printer or otherwise to help you make a stencil.
6. A second person to make your life easier towards the end.