The Smithsonian uses glass lids held in place with the traditional fruit canning mechanism: a rubber
gasket and a pressure seal applied with the metal lever lock. Though the teflon covered threads
Bruce Bartrug wrote:
> Catherine Bursh wrote:
> On the tape subject.... Anyone know the correct tape to use to seal the
> lids of specimen jars with alcohol in them? I'm tempted to use black
> electrical tape but not sure if the alcohol fumes will mess with the
> glue on the tape.
> The purpose of the tape is to slow the evaporation that takes place even
> with a threaded top.
> Catherine, I have two suggestions for you -- neither of which, however,
> I've actually tested for the purpose you indicated.
> The first is teflon plumbers' tape. Which is not really tape per se (it
> has no adhesive) but is simply a thin film of a very inert and useful
> material. One wraps the tape on the threads to be sealed and tightens
> the lid. Very good at sealing the slightest leaks, even in gas lines.
> I used it many decades ago to seal brass joints in gas lines for
> chromatographs -- a instrument used to analyse chemical substances. Try
> to find some wide enough to fit the threads in question.
> The second is a type of seal used to seal lids of packaged chemicals.
> It's a circular sleeve of shrink-wrap type material that one positions
> around a jar or bottle lid and then shrinks with a hair-dryer.
> As I said, I've not tested these specifically for the application you've
> mentioned, but I strongly suspect using both would significantly reduce
> alcohol evaporation from a speciman container. I'm suspecting you're
> already using glass jars and metal lids?