These electrets were made of a 75mm disk of arcylic (Lucite). The top electrode was 50mm so the effective area should be around that. These electrets were made using the technique outlined on the main electret page.

Note: These electrets were made, wrapped and put on the shelf on July 25, 2006. They won't be unwrapped until a few weeks from there so check back later to see if they worked.

Making the Electrets

I made two electrets, the first was melted to the point that it was obviously soft but not tacky and the second was melted to the point that touching it with a piece of wire and then pulling the wire away caused the wire to pick up a strand of melted acrylic.

Showing the 6kV voltage (6 volts * 1000)

The two wrapped electrets sitting on the shelf. The cylinders are just weights to keep the wrapping on well.

For the second one, I preheated the top electrode by blowing hot air onto it with a heat gun in an effort to get more even heating of the acrylic. For the both electrets I used 6kV. I melted the second electet more than the first. Also, I let the first cool only 20 minutes whereas I let the second cool 30 minutes. After wrapping the foil around the first one, the top and bottom still felt very hot, though it was solid. This means a lot of the molecules were still vibrating around and so not necessarily with their polarities hardened in place. I figured this was not good so I let the second one cool an extra ten minutes.

Be sure and check back in a few weeks for the results!!!