On Thu, 18 Dec 2014 14:16:35 +0000, Martin Brown wrote:

Is that based on dry ice? I sort of looked at using dry ice but
the
places I could find only wanted to sell rather large quantities,
10
kg or more.

Sounds about right. 10kg block of dry ice will keep nicely for a week or
so inside one of the thick polystyrene boxes with a bit of additional
polystyrene around it ...

That long. Longevity in storeage wasn't really mentioned but making
2+2=5 I got the impression it sublimed fairly quickly as almost every
where effectively made to order.

... (you don't want a gas tight seal).

I wonder why that is? B-)

You might be able to cadge some for a nominal sum from your local
university physics department if you explained what you want it for (as
opposed to dodgy Jekyll&Hyde/Pangalactic gargleblaster drink additive).

I don't know anyone in the local University Physics Departments.

It is annual Xmas lecture season and we were out supporting the RSC last
night in Newcastle.

Unless ...

--
Cheers
Dave.