[Prev][Next][Index][Thread]

Re: Static Gap Stains

At 10:25 PM 10/17/96 -0600, you 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,

What you are seeing is vaporized copper that has condensed on the PVC
walls. Eventually enough deposits will form to cause the gap to short out.
If you have a fan blowing thru the gap it will help but the deposits are
going to form anyway.

At first I didn't epoxy down my electrodes either. But I got tired of the
spacing changing on me all the time. So I took it all apart and sanded away
the copper deposits on the PVC wall and epoxied the electrodes down. My
spacing hasn't changed since. I occassionally clean up the elctrodes with
some 600 sandpaper. No problem.

If you do decide to epoxy down yor electrodes look for some good strong epoxy.
A couple of types of typical hobby type epoxy that I tried would soften
when subjected to heat.
Mike Hammer
mhammer-at-midwest-dot-net