Performance degrading over time

To: tesla-at-pupman-dot-com
Subject: Performance degrading over time
From: "Ron West" <ronwes1-at-juno-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sun, 12 Mar 2000 17:08:22 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

I am tuning a 4" coil using a 15/30 NST for power.  Last night I had
roughly tuned it in at 5 3/4 turns using a SG and a 16.8nF MMC. 
Everything was working quite well giving 12-15" sparks (not a lot but
much better than my previous ignition coil power supply gave me) when
tuning seemed to go out the window.  I found myself having to adjust the
gap smaller and smaller, chasing that 'sweet spot'.  Something seriously
wrong here.  In the end I managed to fry one leg of the NST, probably due
to my safety gap being set too wide (it never once fired).

One thing I am wondering about is the SG, which is made of 7 gaps using
stainless steel bolts.  It doesn't get very hot, but it was blackened and
pitted after probably no more than 15-20 minutes duty.  I've ground them
down smooth again and I'll be able to try the coil again tonight to see
if performance is back to normal.  But the question I want to ask is
whether the oxidation of stainless steel could produce compounds which
would impair conductivity and produce the kind of problems I'm seeing.

Ron West