Re: Cylinder Static Spark Gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

I can't comment on how easy this was to build, since I
built it ten years or so ago, but here's how I did
mine:

http://www.hot-streamer.com/adam/TCBOR_gap1.jpg

http://www.hot-streamer.com/adam/TCBOR_gap2.jpg

Cameron, note the fan is identical to the one you
recently posted in your series gap.

At the time, I was still learniing and wanted to have
two sets of gaps that I could run in parallel or
series. I also liked the brass bolts on every pipe,
allowing me to pick a wide range of gap spacing.

I used coppper fittings; not cut pipe. If I recall, I
simply drilled the holes one size larger than the
bolts. I then used a small dab of high temp epoxy and
snugged the nuts down. I did one at a time, making
sure the first was square. After that, it was simply a
matter of using a shim and gluing/snugging the nuts
into place. Since I had bolts and nuts in addition to
glue, I could proceed to the next one, without
worrying about disturbing the glue. The fan looks
identical to the one

However, the best performing static gap I built is
this one:

http://www.hot-streamer.com/adam/shopvac_gap.jpg

Very simple to build, and adjust. I've run it with my
leaf blower, and my shop vac set to blow and suck. It
seems to work best as a sucker gap. I've run it as
high as 13 kVA before I melted the solder and had to
replace two pvc bushings. I've run it at 3 - 4 kVA (if
memory serves) with no problem whatsoever. 13 kVA was
for Halloween and I got carried away. I used it on
this:

http://www.hot-streamer.com/adam/bigass_coil/coil09.jpg

It actually worked fine at lower power, but when I got
carried away, it just got too hot.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Barton B. Anderson"
> <bartb@xxxxxxxxxxxxxxxx>
>
> Hi Glen,
>
> Wow, all these methods everyone has brought up is
> neat. Hey, but my
> own is the easiest and will ensure a perfect spacing
> (if that's what
> your after).
>
> First, I've built these gaps using screws to attach
> the copper tube
> to the pvc - yes, it sucks. The problem is too much
> variation bolting
> down a cylinder onto a cylinder. There is a lot of
> effort to maintain
> tight tolerance (drilling, hole position, etc.). And
> yet, even when
> perfect, it can be warped by the screw.
>
> I finally just epoxied the copper tube electrode
> into place (and into
> a coupler which as you will find, has an internal
> lip which can be
> used to set the electrode end onto for positioning).
> I epoxy the
> first electrode into place and try to get a nice 90
> degree angle in
> relation to the internal lip ring. Then, I epoxy the
> rest of the
> electrodes (one at a time) into position by placing
> a predetermined
> spacer between the set electrode and the new one. I
> let it dry in
> place. I usually turn the pvc so that gravity helps
> hold it in
> position. Perfect spacing every time.
>
> I worried about heat causing the epoxy to loosen.
> But, that has never
> happened. I use 30 minute 2 part epoxy available at
> any hardware
> store. There is a type that bonds to plastics and
> metals. That is the
> best to use. I simply add a 1/2" coat along the
> electrode (where I'm
> going to bond it) and set it in place pressing it
> against the set electrode.
>
> I've built these type of gaps that didn't work well,
> but lately, the
> gaps are doing very well! Use 1" to 1.25" size
> copper tubing and
> preferably "precut" at the store (couplings about 3"
> long). Their
> ready to go. However, you will need to mount wiring
> to the gap. So
> first drill a hole near the outer end and attach a
> brass screw and
> nut into position. The electrodes will exit the
> coupler about 1/2"
> which is perfect.
>
> Anyway, epoxy is great stuff for this hobby. BTW,
> it's important that
> the electrode is fully set before putting the next
> electrode into
> position (too hasty and you'll move the electrode
> you thought was set).
>
> Take care,
> Bart
>
> Tesla list wrote:
>
> >Original poster: "Glen McGowan"
> <glen.mcgowan@xxxxxxxxx>
> >
> >Trying to build a Cylinder Spark Gap out of a 6"
> piece of PVC (it's
> >actually a coupler not an actual piece of pipe).
> Currently using 1"
> >x 4" (ish) OD Copper pipe. Between 6 and 8
> electrodes. There must be
> >an easy way to layout and drill the holes. I've
> tried to use exact
> >measurements but I didn't get the results I was
> looking for (which
> >means I can't figure out the measurements). I've
> resorted to trial
> >and error which I'm not particularly impressed
> with. This stink'n
> >thing is making me cross eyed.  I'm almost to the
> point of
> >unplugging the dremel and beating it against the
> garage floor.
> >Figured I'd drop the list a line and see if some of
> the veterans
> >could show me some tricks.
> >
> >
> >
> >