Re: compact oil insulated secondaries?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S Gaeta by way of Terry Fritz <teslalist-at-qwest-dot-net>" <sgtporky-at-prodigy-dot-net>

Hi Jolyon,

I did this last year, and it works great. There is no added capacitance. I
did not have to retune at all for the oil filled secondary. The whole story
is at http://community.webshots-dot-com/photo/17907914/64446200TAzAHL Select the
"normal" viewing mode rather than "Fit window" so that you can read the
text, or you can click the "view full size" thingy under the photo to get
the big picture.

In previous experiments involving Shell Diala, I found that the oil attacks
RTV (Silicone) adhesive. It also attacks my Minwax quick drying
polyurethane. I went to a plastic distributor and got some Lexan. This bonds
well to PVC with Cyanoacrylate (Tak Pak) adhesive. The Tak Pak literaly
melts the PVC and the lexan a little bit so that both of the parts being
bonded really do become one. The pieces have to fit together really well
though. The pipe must be cut really flat so that it contacts the lexan along
the entire edge. I laid four Seals All beads vertically along the secondary
to hold the wire in place. I also laid two vertical beads of Tak Pak just in
case the Seals All failed. After a few months passed, I found that the Seals
All did in fact fail! I can see through the lexan at the top of the coil,
and the Seals All came right off the winding. The winding is in good shape
though. It's a good idea to use clear tubing if you can get it so that you
can see what's going on in there. The problem is that the clear stuff is
expensive. PVC is free if you know where to look for it ;-)

Sue


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, April 23, 2003 10:06 AM
Subject: compact oil insulated secondaries?


 > Original poster: "Jolyon Vater Cox by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >
 > Dear List,
 > I am considering building an oil filled secondary
 > to improve durability and increase compactness in a small TC in which I am
 > currently using a secondary of 880t of 32swg enamelled copper wire wound o
n
 > a former measuring 10.875" long x 2.98 diameter.
 >
 > My reason for doing this is because I am planning to double the number of
 > turns by winding a new secondary using 40swg wire on the same former
 > and there may be insulation issues to be considered here.
 >
 > What is envisaged here is a double-walled cylinder made from two
 > plastic  tubes of dissimilar diameter the winding wound on the smaller
 > inner tube with the oil contained between this and the larger outer tube.
 > the ends of the tubes plugged with rings cut from a polythene chopping
 > board and sealed with silicone.
 >
 > I am anticipating cutting the rings from the board using a  hole saw
driven
 > by an electric drill with cutting blades of different diameters- will this
 > be OK?
 >
 > Has this method of construction been tried before and  is
 > containment/leakage of the the oil likely to be a major problem?
 >
 > More importantly, what is effect of the oil on primary-to-secondary
 > capacitance -are there tuning issues to be considered with this?
 >
 > Jolyon
 >