compact oil insulated secondaries?

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

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 on 
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