Re: why small is better

["sundog" <sundog-at-xxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Hi All, Chester,

I have to agree that small coils are great.  Eventually almost
everybody wants a bigger, better coil, but a small coil will teach
you a *lot* about coils without breaking the bank for parts (read
Tank caps!!!)  Plus it's less crash and bang than a bit 8' high
monster when it runs.  I've learned volumes from the 2" forms I
run.  And with only a few hundred feet of wire on them, I don't
mind burnin' them up.  $12 for 10' of 2" PVC, and ~$40 for a 10lb
spool of 26ga wire (lasts many, many, many, *many* secondaries!).
The good Formvar stuff.

Wanna tinker with a coil?  Use a small one!  You won't spend much,
the tank cap is easy to make nearly indestructable, and if
something does burn, you aren't out a lot of cash.

 Small is cool, but doesn't necessarily mean "tame" or "safe"  My
2" coil has plenty of power to set things on fire (and has!), so
just 'cause it's small and cute don't mean it won't bite.  Think of
them as piranah.  Neat to have, but still deliver a real nasty bite
:)
                Just my $.02
                                                      Sundog

-----Original Message-----
From: Tesla list <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Friday, November 10, 2000 7:27 PM
Subject: why small is better


>Original poster: "chester lowrey" <hilo90mhz-at-hotmail-dot-com>
>
>     i would just like to share my story with the list of how my
knowledge
>of teslacoils came to be, from my very poor beginings to finally
>undrestanding most of the theory and workings of a teslacoil. i
think this
>may be helpful to some beginers thinking of building their first
teslacoil.
>      First of all the main problem with me is that i started WAY
to large,
>the first teslacoil i ever made had a 6" secondary by 2' long
wound with
>24gua copper wire, the reason i made it so large is because i
thought this
>would give me larger sparks even if my powersupply was very small.
also one
>reason it was so large is that my dad owns a lathe so it only took
me about
>30min to wind the whole thing.
>       the primary went through manny stages of development, it
started off
>as a slapped together bunch of poorly aranged 1/4 refrigerator
tubing with
>17 turns maximum. eventually i took the time to build a nice
former out of a
>cutting board with holes drilled in it. if you are a beginner i
would highly
>recommend starting with a primary coil made with wire ties, mainly
because
>wire ties allow you to have a solid connection for each primary
turn as you
>put in on the former. for me i had to bend the copper pipe to
exactly the
>shape it needed to be, this is very hard as any change made to a
turn
>affects all the other turns.
>      my spark gap was 8 1/2" copper tubes 4" long aranged on a
cutting
>board with holes drilled in one side and then tapped to accept
machine
>screws. this design worked fairly well as it was easy to change
the gap
>spacing because you dont have to fool around on the inside of a
pvc pipe
>like the RQ design gaps, but the down side is that it had to
forced air
>cooling or quenching (with my powerlevels it never even got warm).
>      my prized NST (neon sign transformer) was a 12kv 30ma
magnetec one
>that i got for 42$$ used at a local neon sign shop (i live in
hawaii and
>dont have manny choices of where to buy things).
>      for a toroid i used 4" plastic ducting from a dust
collection system
>and covered it with aluminum tape it is 12" diameter
>        capacitor (almost forgot this important element) i used 6
beer
>bottles in parallel for estimated uf of .0066 which is optimum for
the 12kv
>30ma NST, also tied a flat poly plate cap with alum foil
electrodes (i
>killed it by opening the spark gap up to farr). lastly i bought 50
.1uf
>3000volt poly capacitors to make a mmc with, i aranged them in a
string of
>15 for .0066uf 45kv (very overrated). ALL these capacitors
performed very
>similar proving that salt water bottle capacitors are a very good
choice for
>the beginner.
>
>       Results: the spark length from this coil was very
dissapointing, the
>max length was about 7" im still not really sure why it worked so
poorly,
>maby it was just me not knowing how to tune it properly because
the primary
>was 17 turns and i didnt really know anything about resonance.
also tied was
>a 6" coil 2' long wound with 28 gua, a 4" coil 2'long wound with
24gua all
>with similar results.
>
>just recently i have also redone this entire setup with new RQ
gap, new
>capacitor and some other improvements, since i now understand
tuning i have
>been able to get 20" sparks.
>
>
>
>
>NEW COIL
>       after being theroughly (bad spelling) dissapointed with
that coil i
>didnt do anything with tesla coils for about a year and a half.
>then just 2 weeks ago i was surfing the web and came across a few
tesla coil
>web pages. this sparked my memory and i wanted to again try and
build a
>working teslacoil. but this time i wanted one that worked !! it
seemed to me
>that a very small table top coil would be real nice to have and
play around
>with as i could keep it in my room also.
>
>       this eventually led me (after actually calculating the
dimensions,
>unlike the first time) to build a very small 1 1/4" wide 12" long
secondary
>wound with 28 gua on a PVC former.
>       primary is 16gua solid aluminum electric fence wire (i had
a roll of
>it laying around) 15 turns on a 10" diameter plexie glass circle
with a line
>of holes drilled in it every 45 degree. the holes are spaced 1/4"
i then
>used small wire ties to secure the aluminum wire to the plexie
disk. this
>was the easyiest primary i have ever made and looks GREAT all the
turns are
>in perfect alignment.
>
>       power supply: small 7kv 20ma NST (voltage is a estimate
because it
>doesnt have a label, but i did measure current with a multimeter)
>       spark gap: single pipe gap (1" copper pipe 3" long)
>       capacitor: .0044-.01uf mmc (variable by changing how manny
capacitors
>are used )
>       topload: 3" stainless steel sphere
>
>       results:
>                with the 3" sphere max spark length is about 6"
and coil
>tuned at about 4 turns on the primary.
>
>                i have also tried using a pamelo( large 6"
diameter fruit,
>looks like a gigantic orange) as a top load, just to see how long
a spark i
>could get with a bigger topload. and sure enough i was able to get
9" sparks
>to a grounded rod from a screw pushed into the fruit (breakout
from pamelo
>was very small without a breakout point). coil tuned at about 7
turns with
>this larger topload.
>
>        overall i am very pleased with these results and will
continue to
>experiment with this mini coil design to hopefully improve
performance even
>more.
>
>        please excuse all the spelling mistakes and such if any of
the info
>contained in this is wrong please let me know i am very sorry if
that is the
>case.
>
>
>      chester lowrey
>
>P.S. there are some old pictures of my LARGE coil setup on my web
page, but
>i havent had the time to photograph the new mini coil yet. as soon
as i do i
>will put them up on my page.
>http://www.geocities-dot-com/hilo90mhz/
>
>
>some thanks are also in order from the two web pages that gave me
ideas on
>this new and improved coil:
>
>http://www.angelfire-dot-com/ga3/tesla/ Greg for his primary made out
of wire
>ties
>
>http://www.powerlabs-dot-org/ Sam Barros for the idea of a small
compact
>efficient teslacoil
>
>Chester Lowrey  (AKA MŽ. Penguin)
>---------------------------------
>"if all else fails, BLOW IT UP!!"
>
>
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