Useing silicone encapsulants for HV

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

Original poster: "Mike Harrison by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mike-at-whitewing.co.uk>

I'm planning my next Marx generator, and am thinking of using 2-part clear 
silicone encapsulant to
insulate much of it to avoid corona loss.
The plan is to use  folded 3mm thick actrylic section as the main upright, 
with two 'V' sections,
which will be filled with encapsulant,forming a triangular potted section.
This will cover the charge resistor chain and the ends of the caps.

Anyone have any good/bad experience with this stuff ?
Any pointers to UK suppliers would be appreciated - the only one I can find 
at the moment is RS, and
their price is UKP30 (~US$50) for 450g, which seems rather a lot....

I'm assuming silicone is th etype to go for, as I want it reasonably clear, 
and flexible enough to
avoid cracking.