Re: Glass Disks for the Wimshurst Machine From Hell (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 24 Jul 2003 19:21:23 -0300
From: Antonio Carlos M. de Queiroz <acmq@xxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Glass Disks for the Wimshurst Machine From Hell (fwd)

High Voltage list wrote:

> From: John Doran <johnd@xxxxxxxxxxxxxxx>

> The Wimshurst machine will then have disks about
> four feet in diameter; it'll be a whopper even by historical
> standards.  Consider, though, that if you are going to
> go to the trouble of building one, it might as well be
> a big one--it probably wouldn't be that much more difficult
> to fabricate than a table-top unit.

May work, but regular glass is too conductive. You will have to
cover the surface, after drying it by heat, with a thick layer
of varnish to keep moisture off. Or find borosilicate glass.
A test for glass is simple: rub it with silk (or many other materials).
If it gets some charge by friction, you can use it.
Make it sure that the glass is uniformly thick and the disk is
perfect.

Antonio Carlos M. de Queiroz