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Re: Static Gap Stains



Tesla List wrote:
> 
> >From tesla-at-america-dot-comThu Oct 17 21:27:01 1996
> Date: Thu, 17 Oct 96 07:59 EDT
> From: Bob Schumann <tesla-at-america-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Static Gap Stains
> 
> Hello all,
> 
>         I built the cylindrical static gap (Richard Quick type)
> and have a question if anybody else has seen this happen to
> their gap. I followed Richard's instructions almost to a tee
> but I could never bring myself to permanently glue the copper
> electrodes in place. I have access to a polishing wheel that
> puts a mirror shine on them. When it is time to clean the gap,
> I remove all the electrodes and polish them. I have to go
> through the re-gap and alignment routine each time but I just
> can't get myself to touch sandpaper to them. Anyway...with
> the electrodes out, I notice vertical brown stains on the green
> SDR35 PVC innerwall between where every electrode (gap)was.
> 
> Even though I have not scrubbed at the PVC because the stains
> are harmless, they will not merely wipe off.
> I am just curious what does this. Is it the x-rays or UV from
> the spark possisbly that affects the PVC? Such as the PVC
> gets a 'sunburn'? Of course this is of no operating consequence
> as the gap works as well as ever, I just wondered what did it.
> 
> Comment welcomed!
> Thanks
> Bob Schumann

Bob,

I've seen the same thing. I think you ARE seeing the effects of the high
intensity UV coming off the gaps (tells us not to stare at them, doesn't
it (:^)). Most plastics, unless UV inhibited, are negatively impacted by
UV - the PVC is structually changing, and "yellowing" in the process.
Other than this cosmetic change, I haven't seen any other negative
effects.

I've also seen redeposited copper vapor and oxides where the airflow
patterns come thru the gaps. Since I have a tandem gap (one set above
the other in one PVC tube)), I need to remove these deposits once in a
while to prevent surface flashovers between electrode sets.

Safe coilin' to ya!

-- Bert --