RE: Sealing Plexiglas

To: tesla-at-pupman-dot-com
Subject: RE: Sealing Plexiglas
From: Ted Rosenberg <TRosen1-at-Tandy-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 13 Dec 1999 17:37:40 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

JW: That's quite a list. To be candid, I am not taking into account the
electrical properties of the winding sealing material. I looked on the can
label of this Minwax Satin and no mica is listed (?).

I plan no 'base coat'. Once the winding is on the coil, I will apply the
Minwax as a motor slowly turns (4.8RPM) the tube for an even application and
dry. Looks like one coat/nite. Maybe 4-5 coats.

There seems to be an extremely wide variety of brands, formulas, etc for
sealing material that I almost think one could become a chemical engineer
and bog down in the analysis of the sealing material and never get to use
any!

Believe me, I will let all know how my efforts go and hopefully, they will
turn out OK.

Ted
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Original Poster: "jw" <jwhitmor-at-muscanet-dot-com> 
Subject: Sealing Plexiglas


>Original Poster: Ted Rosenberg <TRosen1-at-Tandy-dot-com>
><snip>
>Has anyone actually sealed a secondary on Plexiglas with a 'material' that
>worked? if so, what and where and how much (US$ please).

I too have purchased a rather expensive piece of acrylic tubing.
and am experimenting with a sealer that has not been mentioned yet.

It is  the new class of non-yellowing WATER based acrylic varnish,
marketed as "environmentally friendly" clear wood finish. One brand
I am experimenting with is "Flecto Varthane Diamond"
(some other "Varthanes" are solvent based).
I have coated test pieces of Plexiglas with it with no crazing at all.
The big questions remain as to dissipation, dielectric strength, moisture
retention etc.. I plan to heat cure the finish and then do more testing.

curious note: satin varnish, is made with mica flakes; better insulation?

Some other coatings that come to mind are:
High Solids 2 part epoxy (I have "West Systems Epoxy"; does not hurt
styrene)
Water borne urethanes
Water borne epoxies (airplane fabric coating)
carnuba wax
"no odor" (acetic acid free) RTV silicone rubber (regular RTV corrodes
copper)
conformal coatings used for printed circuit boards.

If the coating is as hygroscopic as the base material,
there is no point in a base coat; but the coating may still be useful
as insulation and as fixative to hold the windings in place.

Does any coiler have experience with these proposed "plexi-safe" coatings?

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