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Re: [TCML] A new guy with a primary threaded through holes
I managed to wind 50 feet in, then splice another piece to complete nearly 20 turns of 1/4". I'm sure I could have gone into pages of technique, if asked. As you discovered, there only a handful of us who have succeeded, so no one's really interested in technique. At first the whole thing rotates, but pretty soon, you become master of scootching. I used Lexan and my glue failed partway into the wind. I unwound the forms a fraction of a turn then screwed it into the base.
--- On Mon, 5/17/10, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
> From: Joe Mastroianni <joe@xxxxxxxxxxxxxx>
> Subject: [TCML] A new guy with a primary threaded through holes
> To: tesla@xxxxxxxxxx
> Date: Monday, May 17, 2010, 8:55 PM
>
> My primary coil - http://gallery.me.com/iceowl
>
> It is with no small degree of chagrin that I note Greg Leyh
> will not be appearing at this week's Cal. Maker Faire.
> Were it not for his demonstrations last year I would not be
> reading this list now, and typing with raw fingers after
> threading 42' of 1/4" copper tubing through 96 stanchion
> holes. I am in process of creating my first coil
> thanks to Greg and his small 20' purple arcs that spanned a
> big chunk of the show floor.
>
> Alas, even the wife was so taken by Greg's display that she
> consented to my coiling. Even encouraged me. Is
> even helping. Four hands winding the copped
> through the holes worked better than two. This is how
> it starts, I guess.
>
> Ebay luck shone down upon me a few months ago and I scored
> 15/30 NPT. I promptly built a jacob's ladder, and just
> as promptly grew bored with it. Consequently I have
> been amassing parts to build my first
> coil. The garage is beginning to fill with
> those white/red/blue Priority Mail boxes. I can barely
> get the car in. After a trip to TAP plastics and an
> evening throwing numbers into JAVATC I decided to start
> building. Now there is no room for the car at all.
>
> Previously, I had bought an 18 page paper written by a guy
> who went through the mechanical structure of a static spark
> gap coil, and he advocated using plastic cutting board
> material for the stanchions, and using
> 4. Four seemed to offer less structural
> integrity than 6, and 6 (or 8) looked better. I
> decided that it would be very difficult to thread the copper
> around 8 stanchions placed 45 degrees apart because of
> friction and also, the 1/2" polycarbonate would force the
> copper to follow a straight line through its 1/2" length,
> which I felt might necessitate lots of bending. So
> 6. I decided on 6.
>
> I built 6 stanchions to hold the primary by cutting "L"
> shaped pieces from 1/2" polycarbonate/Lexan I got from the
> Tap plastics cast off bin. With my drill press I built
> a jig out of wood which allowed me to precisely drill 15
> holes in the long leg of the "L". I drilled 5/16"
> holes and stepped them inward by a couple 32nds on each
> subsequent stanchion to account for the spiral
> winding. There is no engineering involved in my
> decision to drill 5/16" holes other than I knew I wanted a
> hole bigger than the O.D. of the 1/4" tubing and the only
> bit for drilling plastic they had at Tap plastics that was
> bigger than 1/4" and smaller than 1/2" was
> 5/16". Turned out to be
> fortuitous.
>
> That evening I subscribed to pupman.com - which I had not
> previously subscribed to because, well, no pictures.
> What a massive mistake. I learned at about 2AM on
> Saturday morning that it would be impossible to thread the
> copper through the 1/2" polycarbonate. Several had
> tried and failed, as evident from their exasperated postings
> on this auspicious site.
>
> But I had already made my investment in time and $$.
> So my choices were to toss out what I had done and go the
> LDPE-with-"C"-shaped-notches-instead-of-holes route, or
> beaver on mindlessly as if I had never read the posts.
>
> The next morning acrylic cement I glued the stanchions to a
> lexan circle I also got at Tap. When you use that
> acrylic cement it bonds pretty completely. It's as if
> the plastic becomes one piece. This was
> also fortuitous.
>
> At 2AM on Sunday morning I discovered some posts on pupman
> that described some intrepid soul, some years ago, who
> actually accomplished what I was about to try.
> Somewhat cryptically he said, "it's possible and I just did
> it and it wasn't so hard". Though he did
> not describe his technique much other than to mention the
> term "scootching".
>
> I have learned what "scootching" is. But just to be
> safe, and to allow for extra play, I beveled (countersunk?)
> each of the holes about 1/8" with a fine stone bit on a
> dremel. I figured this would make it easier
> to thread the copper as it came in to each hole at an
> angle.
>
> When daylight broke I began threading the copper. Even
> though my stanchions have more holes, I had decided to
> thread 13 clockwise turns. The 50' section of copper I
> got came in a coil. I laid this coil over the
> stanchions in the winding sense I desired and began
> threading the tubing using the natural curve of the copper
> to follow the curve of the hole pattern on my
> stanchions. The first 2 turns went swimmingly, and I
> wondered what all the fuss was about. I put two hands on the
> tubing, forcing it through the holes gently, turning it as
> if it was some sort of valve. I could push the copper
> through the holes about 1/2" with each grunt. The next
> 4 turns were a bit harder. And in fact, by the time
> the 4th turn was through, I could only move the copper about
> 1/8" or maybe only a couple millimeters with each effort of
> the hand. This took me about 90 minutes.
>
> With a cup of coffee in hand I took a rest break, read more
> pupman, and discovered someone suggested using Windex as a
> lubricant.
>
> I will say it would have been completely impossible to
> thread the copper through the holes without some form of
> lubricant. By the 5th turn the friction was so great
> the coil could not be passed through the stanchions at
> all. Slathering on windex - I suddenly had the ability
> to "scootch" the coil clockwise about 1/16" with each
> twist. It didn't get much better than this. In
> fact, it got worse. As I reached the inner turns of
> the coil, I was squirting Windex into each hole pretty much
> with each turn of the coil. By the time I
> got through the 10th turn, the coil was only rotating 1 or 2
> millimeters with each "scootch". I had to manually
> twist each turn of the coil individually, sometimes starting
> from the inside, sometimes from the outside.
>
> I believe I have put six hours into the coiling of the
> copper. It was not easy. The results seem to be
> aesthetically pleasing, and of course, it's very
> structurally rigid, especially since the windex has all
> evaporated now.
>
> With regards,
>
> Joe
>
>
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