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Re: Best Secondary Surface coating
From: Chip Atkinson[SMTP:chip-at-XiG-dot-com]
Reply To: Chip Atkinson
Sent: Wednesday, November 19, 1997 2:03 AM
To: Tesla List
Subject: Re: Best Secondary Surface coating
> I would strongly recommend not using water-based polyurethanes, this
> stuff is crap IMHO.
I concur. I have had poor luck with the water based stuff. I doubt if it
was the sole cause of the problems, but I used it on the only coil that I
never got any sparks whatsoever.
> stuff- it takes WAY too long to dry. Also, I am curious if anyone has
> used Behr's Build 50; this is the thick epoxy coating that is used to
> make those tacky bar counters with the old coins in them... It's
> supposed to be as thick as 50 coats of urethane, but it's also designed
> to be applied to flat horizontal surfaces, to prevent running and
> pooling, so I have my doubts about getting it to work on a cylindrical
> coil.
I have used the Supergloss Build 50 and had pretty good results. However,
there are two things to keep in mind. First is that you need to keep the
coil form turning while the stuff dries, about 4 hours in the summer
(don't try it in the winter cold, it will take way way too long). Second
is that the rate of thermal expansion and contraction is different than
the PVC and copper of the form and winding. It's no problem in general,
but if you get a cold snap, you should bring your coated secondary
indoors. I had the coating on a coil crack all over when the temperature
in the garage reached 0F or lower (-18C).
Chip
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Chip Atkinson; Xi Graphics 1801 Broadway, Denver CO 80202
(303)298-7478voice (303)298-1406fax (800)946-7433sales
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