Re: wood RSG

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Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


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From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, December 28, 2001 5:17 PM
Subject: wood RSG


> Original poster: "Mr Gregory Peters by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>
>
> I am having difficulty finding some cheap epoxy/fibreglass sheet to use
> for a RSG.

You can use a stack of standard glass epoxy circuit board material.  At
worst, you could get old PC motherboards, etch all the copper off with
nitric acid, etc.

The stuff is also available as a standard structural material.  Call
suppliers of structural steel and aluminum. You might run into a minimum
order problem, but, then, if you ask who they supply to, you can call their
customers and get offcuts or scraps.

I was wondering if anyone has ever tried using well dried
> and prepared plywood? While it isn't the best insulator, I would
> imagine that a polyurethane coated disc of about 10-12" diameter would
> probably insulate well enough. Another plus is that high grade plywood
> can be very strong and is probably better at handling high temperatures
> than most plastics. It is also cheap and easy to work with.

My experience has been that high grade plywood (suitable for this kind of
use) is going to have lots of very thin plys of some hardwood (one grade I
am familiar with here is 11 ply Finland Birch and is just under 3/4" thick),
and is not particularly cheap.

If you're going to the trouble of vacuum impregnation, you might as well
make your own glass epoxy composite. Why bother impregnating wood when you
could just impregnate glass cloth.