[Nhcoll-l] PTFE tape on jars

[John E Simmons]

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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