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Re: outdoor coils

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi Bart, all,

I second the use of marine spar varnish for this purpose. I, too,
have had no problems with any cracking or shrinking due to
seasonal temperature changes here in the Memphis, TN, with the
use of Minwax marine spar varnish. Though our winter temps
aren't near as rigorous as those of MN, it does still get cold
enough that coefficient shrinkage could still definitely be an
issue.

David Rieben


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, November 17, 2005 12:16 AM
Subject: Re: outdoor coils


Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Chris, Robert,

Interesting! I'm in CA these days but started coiling in Minnesota which is cold cold cold. I didn't use PVC but sonotube at that point which I did coat inside and out with a thinned-out urethane (to absorb into the sonotube). Due to the temp swings, I decided to use Marine Spar Varnish for the outer coating. This particular varnish remains flexible (hard to the touch). I've never had any problems with cracking, shrinking, expanding, etc.. Just wanted to mention that as it's available at all hardware stores. Even though I'm in sunny CA, I still use the same varnish. It's been a nice varnish and goes on thick.

Take care,
Bart

Tesla list wrote:

Original poster: robert heidlebaugh <rheidlebaugh@xxxxxxxxxxxxxx>

Chris: I am at 7200 ft alt.so temprature extreams are a serious problem.PVC
has a large expansion ratio so it is very important that your coating be
well bonded to your coil form or the secondary coil will slide off the coil
form in cold weather. I beleave I have finaly solved this problem by rough
sanding my coil form and pre coating the form before winding my coil while
the coating is still slightly soft so the wire will not slide off. I have
had my coil drop 2 inches down the coil form in the cold.
   Robert   H