"John Keith" wrote in message
news
As I noted in a follow-up message my application is not for a stove
installation. I only referred to the stove application because in my
past experience I used some 1/4" asbestes material and that (minus the
asbestes) was exactly what I was looking for again.

After experimenting with the 1/4" hardibacker material it looks like
it will be perfect for my situation. I was even able to make some good
3/4" round holes that I'll need (I'm sure thehole saw will be shot by
the time I'm done.)

Rona Hardware carries cement/fibreglass
board made by Beltway (Bestway?) and
recommends 6 mm thickness (quarter inch)
for shielding. Its Shielding Panels are
good one side but max 4 ft. square. It also
sells quarter inch and half inch material in
4x8 panels. You may find the quarter inch
is unhelpfully flexible. I did not guess but
imagine the Shielding Panels are specially
stiffened.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)