Re:Re:Secondary form, New idea!!

["Al Hassick" <uncadoc-at-juno-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Alex.   I went and checked out the website, and darned if it didn't
look exactly like the "Quick-tube" concrete form that I used for my 8"
secondary on my third coil.  And my tube did appear to have some kind of
asphalt or other unknown black stuff impregnated within the cardboard
form.  If this a similar type of tube then it will work pretty good. 
However I think that I have read that the 'sonotube' interior is a
superior tube for concrete work (not that my Quick-tube was designed for
Tesla work).  It may be that the interior of the tube is designed more
for a great foundation footer job than it is for Tesla work. I really do
not know. And its interior coating may be detrimental to Tesla work.  I
am not really sure because I have never laid eyes on one.   I can only
quote my experience with the 'Quicktube'  Which has worked very well for
me. But if you are determined to use it, then why not.  Maybe the Tesla
group will learn from your experience.   I get five foot arcs from my 8"
quicktube cardboard form and have run it for over a 60 minutes sustained
run, (thats right, a continuous 60 minutes with no shutdown.).  I have
over 50 hours run time on this coil.  One tip, however.  I did coat the
form with innumerable coats of poly, inside and out, and then gave the
interior of the tube a final coat of fiberglass resin. Maybe it worked
for me because I was patient in my efforts to apply as many coats of
sealer as I possibly could, within reason.  Had I not applied many sealer
coats to the cardboard form, it would probably have caught fire and
melted down!   I guess I  lucked out with a lot of perseverance in
applying many sealer coats on the concrete form.  Also I never "baked the
form' ; but I did use a fan forced electric heater blowing through the
center of the form in between each coat of polyurethane, this made it
cure fast and probably dried up a lot of moisture as a bonus.  The
alternative is to purchase a good low loss form to begin with, even if it
costs more up front.  Only you can decided the path you wish to take, and
the time or expense you are willing to endure.   As far as the bumps on
the form, yes you can practically eliminate them.  You will need to
patiently apply and sand many coats of polyurethane.  But mine still
shows some 'bumps' where the spiral form was fabricated, but nobody ever
comments on that.  They are too engrossed with the spark output to know
any better.  And they seem to accept it as the way a 'Tesla' is supposed
to be!  They are too impressed with the sparks to wonder what the
secondary form is made of !!!!!!        Al.

On Mon, 11 Sep 2000 12:28:02 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: "Al Hassick" <uncadoc-at-juno-dot-com> 
> 
> Hey!  Slather it with as much polyurethane as you can!  The thing 
> here is
> that it sometimes costs more in insulating sealer coats of poly, 
> epoxy,
> fiberglass resin or what have you than it would cost to buy a proper
> secondary form of a low loss material.  But hey, you have nothing to 
> lose
> if you try!  Except the cost of your wire, time and sealers. 
> Experience
> is the best teacher!  Go for it!  I got 5" sparks with a secondary 
> wound
> around oat boxes.   Al.
> 
> On Sun, 10 Sep 2000 15:22:55 -0600 "Tesla list" <tesla-at-pupman-dot-com>
> writes:
> > Original poster: "Alex Madsen" <alexmadsen-at-netzero-dot-net> 
> > 
> > Secondary form
> > 
> > Hi all
> > The 6" pvc I bough for my secondary form I found out was only 
> > covered in
> > white pvc. The inside ¾ is black PVC. I read here some where that 
> > that is
> > very bad due to the carbon used to turn it black. Is this true? 
> After
> > looking around for a while I fond some 6" cardboard tubing used 
> for 
> > poring
> > concrete into for footings and such.  It is strong enough to hold 
> > its shape
> > and support a significant weight + light weight. I as thinking 
> this 
> > would be
> > perfect for coils. It is less expensive then pvc and come in many 
> > diameter
> > up to I think 56".  The technical name for this is "sonotube" Here 
> > is a web
> > sight run by one of the may manufactures of the stuff. There is a
> > description as well as info. on  different sizes and pics.
> > http://www.sonoco-dot-com/sonotubes.htm There are may there 
> > manufacturers. I
> > have some form Mercer paper tubing corp. My plan is to cut off the 
> > ends
> > (which are bent). Dry it well with a heat gun.(to get rid of the 
> > absorbed
> > H2O which may reduce performance) Give the tube several heave 
> coats 
> > of
> > polyurethane and  then sand it smooth.( there are little bumps 
> where 
> > the
> > seams in the sonotube are).  Then I will begin to wrap the tube 
> with 
> > wire.
> > Will this work well? Cements please !!!!!!
> > Here are some pic of the tube i paln to use.
> > http://www.geocities-dot-com/alexmadsen/
> > Alex Madsen
> > PS I think this would be good  for BIG TCs!!
> > 
> > 
> > 
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