Using SF6 for cap..

I posted an idea about using SF6 for insulating a "standard" rolled
LDPE&Al capasitor instead of the oil but got no replies - perhaps because
it was at the end of a rather flaming CP comment.. The good things I have
thought about this: 

- no danger of oil burning/exploding around
- no air-bubbles possible, will replace air everywhere especially
  when a vacuum is pumped first
- SF6 can be replaced every once and a while if necessary
- is not messy/heavy like oil, is heavier than air
- if cap fails it's easy to fix as there's no oil to mess the setup

Any ideas? Comments? (I know SF6 is toxic)

I haven't yet found data on how applicable this really is (pressure needed
etc.) but it might be worth consideration.. I first came to this idea when
a person working with high-power&voltage electronics (doing installations
for power-companies) told me that oils are not used much anymore but SF6
is - this was for xformers, switches etc.. 

Just to clarify the design - SF6 is not to be used as di-electric but like
oil to prevent corona etc.. 

  Kristian Ukkonen.