[TCML] Secondary Damage (Large Coil)
ln2guy42 at aol.com
Fri Apr 13 14:49:16 MDT 2012
That sounds fantastic.
Based off of your information, I have a clear idea of the necessary steps I will take:
1). Remove bottom winding (~250 turns) - up until the damaged points.
2). Sand/scrape off the carbonized damage on the coil form
3). Apply thick epoxy resin coat onto the coil form
4). Splice in a new wire
5). Wind new bottom winding
6). Apply thick epoxy resin coat onto the new winding.
Sound all right?
Would you recommend applying the Envirotex over the entire coil, even parts which are already coated with several layers of varnish?
I'll keep you updated about how the procedure goes.
Thank you for your kindness,
From: Bert Hickman <bert.hickman at aquila.net>
To: Tesla Coil Mailing List <tesla at pupman.com>
Sent: Thu, Apr 12, 2012 7:47 pm
Subject: Re: [TCML] Secondary Damage (Large Coil)
Many coilers have had excellent results using Envirotex Lite Pour On
High Gloss Finish. This two-part resin is available in many craft and
hardware stores and it can also be ordered through numerous online
You'll need to set up a well-ventilated, but dust-free (and flying
bug-free!) work area. You will also need to set up a fixture that can
continually rotate the coil form at a surface velocity of ~4 - 5
inches/second. You'll want to apply a relatively thick final coating
(1/16" - 1/8" max). You'll need apply the resin within ~25 minutes or
less after mixing. You'll need to continuously rotate your secondary
while applying the resin, and then continue rotation until the resin has
sufficiently hardened (typically 6-8 hours) to prevent sagging. Some
excellent practical information can be found in the TCML Archives. Look
for the "Envirotex Lite , High Torque drive" thread in the July, 2009
When done right, you'll get a beautiful, hard, crystal-clear coating
that completely imbeds and protects the entire winding. Be sure to allow
your coating to completely harden (2-3 days) before using it in your
Amir Mojarradi wrote:
> Hi Bert,
> Thanks for your helpful advice. Is there a particular brand or type
> of epoxy or polyester that you recommend? I know other forms of epoxy
> exist, but the only products I have seen at major hardware store are
> the small, "5 min" epoxy tubes. Would these be sufficient?
> Thank You,
> Amir Mojarradi
> -----Original Message----- From: Bert
> Hickman<bert.hickman at aquila.net> To: Tesla Coil Mailing
> List<tesla at pupman.com> Sent: Thu, Apr 12, 2012 8:18 am Subject: Re:
> [TCML] Secondary Damage (Large Coil)
> Hi Amir,
> The insulation between turns has been damaged, possibly by a strike
> to the winding, an arc-over from the primary to the lower part of
> the secondary, or by handling. Strikes to the secondary can be quite
> damaging on larger coils such as yours. At the very least you'll need
> to remove the windings around the affected areas, or remove the
> bottom portion of the winding since the coil form may now also be
> carbonized underneath.
> Once the winding has been removed from the affected areas,
> scrape/sand away any traces of carbonization from the form before
> applying new wire. Once you have repaired the winding, you may also
> want to consider applying a thick 2-part polyester or epoxy coating
> over the winding. This will protect it mechanically as well as
> helping to prevent any future damage if you get another strike to the
> secondary. The strike will harmlessly spread out along the surface of
> the coating instead of destroying the insulation/wire at a single
> concentrated point.
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