[Nhcoll-l] PTFE tape on jars

[Tony Irwin]

Parafilm (see http://en.wikipedia.org/wiki/Parafilm ) has been used in the
past for external sealing of jars. I'm not sure how effective it is in the
long term.
Tony.

Dr A.G.Irwin
47 The Avenues
Norwich
Norfolk NR2 3PH
England

mobile: +44(0)7880707834
phone: +44(0)1603 453524


On 11 January 2014 02:34, John E Simmons <simmons.johne at gmail.com> wrote:

> Paul,
> Whether or not the Teflon (PTFE) plumber's tape helps will depend on
> quality of the closures on the jars. If the closures are made of good
> plastic (such as flexible polypropylene) or metal that is not oxidized, and
> have a good liner (e.g., a Teflon liner or in the case of metal lids, a
> compressible gasket around the inner edge) but the threads of the jar a a
> bit deep or the lid fits a bit loose, the tape can help by closing the gap
> between the jar and the lid. If you have a good quality lid that fits
> tightly on the jar, then its probably not worthwhile to use the tape. If
> you have lids that have tiny perforations (e.g., metal lids with
> micro-oxidation points) or plastic that is very thin or has microscopic
> cracks, then the tape probably won't help.
>
> There is an easy way to test whether or not the tape application improves
> your jar/lid combination. Fill a number of jars with storage strength
> preservative fluid (no specimens!) and close some with the Teflon tape and
> some without. Either mark the fluid levels on the outside of the jar with a
> grease pencil, or better yet, weigh each jar. Put the jars in a water bath
> and heat it to around 40-50C for a couple of weeks, then check the amount
> of remaining fluid in the jars and compare.
>
> --John
>
>
> John E. Simmons
> Museologica
> 128 E. Burnside Street
> Bellefonte, Pennsylvania 16823-2010
> simmons.johne at gmail.com
> 303-681-5708
> www.museologica.com
> and
> Adjunct Curator of Collections
> Earth and Mineral Science Museum & Art Gallery
> Penn State University
> University Park, Pennsylvania
> and
> Lecturer in Art
> Juniata College
> Huntingdon, Pennsylvania
>
>
> On Fri, Jan 10, 2014 at 4:48 PM, Callomon,Paul <prc44 at drexel.edu> wrote:
>
>>  Folks,
>>
>>
>>
>> At least 20 years ago (before my time here), white plumbers’ tape was
>> wrapped around the edge of the lids and onto the sides of all the bottle
>> and jars in a certain section of our alcohol collections. This is the PTFE
>> tape that plumbers use to seal threads; it is thin, soft and non-adhesive.
>> Presumably the idea was to provide a secondary vapor barrier in addition to
>> the jar lid seal.
>>
>> We are now doing long-overdue major maintenance on this collection, and
>> are trying to assess the efficacy of this tape. I’d be very interested to
>> hear from anyone who (a) has used it and can show it works (b) has used it
>> and can show it doesn’t work, or (c) who considered using it but decided
>> not to, and why.
>>
>>
>>
>>
>>
>> *Paul Callomon*
>> *Collection Manager, Malacology, Invertebrate Paleontology and General
>> Invertebrates*
>>  ------------------------------
>>
>> *Academy of Natural Sciences of Drexel University, Philadelphia*
>>
>> 1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
>> *callomon at ansp.org <callomon at ansp.org> Tel 215-405-5096 <215-405-5096> -
>> Fax 215-299-1170 <215-299-1170>*
>>
>>
>>
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>>
>
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> natural history collections to ensure their continuing value to
> society. See http://www.spnhc.org for membership information.
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