Re: Coil Coatings

["Tesla list" <tesla-at-pupman-dot-com>]

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

little bubbles are very hard to avoid.

Two approaches: low viscosity stuff (but, of course, as it hardens, it gets
thick, and then, bubble city..)
Vacuum bagging (which is what the pro's do).

Multiple thin layers might help... lay a slow hardening layer down on the
form, wind the wire, wait for it to cure. Spray on a very thin layer, wait
for cure, etc.etc.  The idea being that at any given stage, there isn't a
very thick layer curing.

One other problem... with the wires closewound, there is a trapped area
under the winding (actually, between wires), which might provide a reservoir
for gases.  A precision space wind might be the solution, but I suspect that
for home use, the vacuum bagging technique might prove to be easier to
implement.




----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, December 01, 2001 11:15 AM
Subject: Coil Coatings


> Original poster: "MakingLightning by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <makinglightning-at-home-dot-com>
>
> Hi Guys,
> I just got done coating an 8" coil with epoxy.
> While it was curing, large bubbles would form and if I blew on them, they
> would go away.
> When everything was said and done, it looks beautiful and I know it is
hard
> because my coil took a fall to the basement floor and I can not tell where
> there is even a scratch.
> But when I look real real close, it looks like there are very very tiny
> bubbles at the level of the wire coating, not in the middle of it, or near
> the surface that you touch, just deep in it.
> What causes this? The big bubbles, which I don't really care about because
> they disappear, and the tiny ones? I used a slow hardener. This is epoxy
> used for boats, Westco brand.
> I know my next question has been gone over in the past, but I am wondering
> what everyone's favorite coating is as of now?
> I hate polyurethane and acrylic turns out to be brittle and these epoxy
> bubbles drive me crazy but it seems the hardest and prettiest. I did use
> Behr build 50 on one of my 4" coil years ago and really can't remember how
> that compares to these now and what exactly that coating was.
> I am practicing coatings on a couple 8" coils for a small TC and want to
get
> things perfect before I go on to coating my 18" coil. So I would like to
> hear other peoples input before I coat the next 8"er.
> Kevin
>
>
>