Smoke machines

Since I posted my initial request for info about smoke machines
(Conservation DistList Instance: 16:13 Friday, August 23, 2002) I
have received many messages both on and off list for which I am very
grateful for all the interest shown.

Many people suggested that I use cold gasses, but one correspondent
pointed out that as the mist is actually condensed water droplets
not the cold gas itself, the mist will disappear as it goes through
the tiny gap and meets the warm air outside the case. Has anybody
actually tried doing this themself and can give their experience?
Unless they have, it is probably not a route to pursue.

The idea of using a smoke machine came from the supplier of some
other cases we bought. I thought the chemicals used may be
effectively unremovable, and the DistList has confirmed these fears
for me.

It was also pointed out to me that pressurising a case, does exert a
large pressure on the glass pane, which may cause mechanical damage,
cracking the glass?

The one surviving alternative measure is (though I am still very
much open to discussion on any alternative, mentioned or new) is to
talk to a refrigeration engineer. They have instruments to measure
small leaks. Thank you again,

Paul Harrison
Metal Conservator
Hong Kong Govt


                                  ***
                  Conservation DistList Instance 16:17
                Distributed: Tuesday, September 3, 2002
                       Message Id: cdl-16-17-004
                                  ***