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RE: Coil Form needed 2



Original poster: "Gary Weaver" <gary350-at-earthlink-dot-net> 

This might be worth mentioning.  About 3 or 4 years ago I posted this
information on the TC list so it may be in the archives someplace.   It has
been so long ago I have forgotten all the details.  I did an experiment to
see if a large coil could be built using small diameter pvc pipe because
large pipe is expensive and hard to find.  I wound 3 identical secondary
coils, connected them all in parallel in the center of one flat wound
primary coil.  I placed a toroid on top and fired it up.  It worked
excellent.  Then I build one large diameter secondary coil to replace the 3
parallel coils the fired it up again using the same primary coil, same cap,
same spark gap, same chokes, same transformer, same toroid, same size
enamel coated copper wire.  As I recall the output sparks were  about the
same on both experiments.   I had planned to build 6 identical secondary
coils and connect them all in parallel but never got around to doing that.
If you are thinking about building a large coil and can not find any large
pvc pipe give this experiment some thought.

Gary Weaver
gary350-at-earthlink-dot-net
Why Wait?  Move to EarthLink.


 > [Original Message]
 > From: Tesla list <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Date: 5/13/2004 3:23:35 PM
 > Subject: RE: Coil Form needed
 >
 > Original poster: "making lightning comcast" <makinglightning-at-comcast-dot-net>
 >
 > I put 2x4's in the form of a cross on the inside of the ends, then
drilled a
 > hole through the middle with a pipe going through the middle.
 > I use bungee cords sewed together that wrap around the tube and then down
to
 > a geared motor. I put a layer of friction tape on the end of the tube for
 > the bungee cord to grip on.
 >
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Thursday, May 13, 2004 10:02 AM
 > To: tesla-at-pupman-dot-com
 > Subject: RE: Coil Form needed
 >
 > Original poster: "Arpit Thomas" <arpit-at-inzo-dot-org>
 >
 > wow, thats not bad at all! I paid 20 dollars for one metre of 6 inch pipe
:/
 > So where do you get the end caps for them? I'm assuming you'll need end
 > caps so you can atach it to a winding machine. 6 inch end caps are about
25
 > bucks each at the local hardware store- all the 6 inch fittings are very
 > expensive.
 >
 > *********** REPLY SEPARATOR  ***********
 >
 > On 12/05/2004 at 10:00 PM Tesla list wrote:
 >
 >   >Original poster: "makinglightning comcast"
<makinglightning-at-comcast-dot-net>
 >   >
 >   >Paul,
 >   >
 >   >I have been able to go to a construction site and just ask some guys
there
 >   >for a piece. Usually an 80 foot 12" is just scrap to them. I got 2 12"
15
 >   >footers for a case of Bud once. I got a 12' 18" one for free also.
Those
 >   >are
 >   >harder to come by, but the 12" ones are used all the time in new
 >   >subdivisions and commercial buildings. They sure are building a lot
 >   >nowadays, so it should be easy for just about anyone to do this.
 >   >
 >   >Kevin
 >   >
 >   >-----Original Message-----
 >   >From: Tesla list [mailto:tesla-at-pupman-dot-com]
 >   >Sent: Wednesday, May 12, 2004 6:03 PM
 >   >To: tesla-at-pupman-dot-com
 >   >Subject: Re: Coil Form needed
 >   >
 >   >Original poster: DRIEBEN-at-midsouth.rr-dot-com
 >   >
 >   >
 >   >
 >   >----- Original Message -----
 >   >From: Tesla list <tesla-at-pupman-dot-com>
 >   >Date: Wednesday, May 12, 2004 9:20 am
 >   >Subject: Coil Form needed
 >   >
 >   >  > Original poster: "Paul Marshall" <klugmann-at-hotmail-dot-com>
 >   >  >
 >   >  > I am looking for a coil form 12" or greater diameter. The length
 >   >  > should be
 >   >  > about 4 times the diameter. Also I am planning on using a 40kV
 >   >  > .5uF
 >   >  > capacitor for the tank circuit. I have a 25kVA pig to drive it.
 >   >  > Has anyone
 >   >  > on the list ever used that much capacitance in their tank circuit ?
 >   >  >
 >   >  >
 >   >  >
 >   >  > Paul S. Marshall
 >   >
 >   >Paul,
 >   >
 >   >I would think that 0.5 uFD would be way too large for
 >   >anything except maybe for an Electrum sized coil. The
 >   >biggest cap that I've used so far is .0825 uFD, but I
 >   >do now have (2) 0.1 uFD, 50 kV Hipotronics custom Tes-
 >   >la caps that I got from Jeff Parrise of KVA Effects.
 >   >I plan on using one of these for my future BIG coil
 >   >project and driving it with a 15 kVA pig.
 >   >
 >   >As for large diametered secondary coil forms, I was
 >   >able to get gray PVC ducting pipe from a local plas-
 >   >tics supplier. I had picked 12" but they had 18" too.
 >   >Of course it was quite pricey, though. I payed over $5
 >   >a foot for the 12" and I'd hate to even ask how much
 >   >the 18" was ;^0 Another cheaper alternative is the
 >   >concrete former tubes. They are cardboard and are
 >   >considered to not be the best form material due to
 >   >higher lossiness and low Q, but if thuroughly dried
 >   >and varnished, they do work. I know from experience.
 >   >My biggest coil to date used a 12" dia cardboard
 >   >"Quiktube" concrete fromer from Home Depot and it
 >   >was only about 38.5" long but gave 8 to 10 ft. sparks
 >   >from a 9x30 toroid and driven by a 10 kVA pig (14.4 kV)
 >   >and with the aforementioned .0825 uFD primary capa-
 >   >citance and a homemade lexan and brass RSG.
 >   >I've seen 24" concrete formers at construction sites
 >   >so you could definitely build a large coil with one
 >   >of these.
 >   >
 >   >David Rieben
 >