[NHCOLL-L:3509] Re: Neoprene rubber stoppers

Thu Jul 26 11:24:43 EDT 2007

There is a better alternative to using screw-caps or snap caps on small
vials.  We use a shell vial (straight sided, no threads, no neck) filled
with preservative, and plug the top with polyester fiber.  Polyester
fiber (which you can buy in large bags at fabric stores as pillow
stuffing) is used because it is inert and because unlike cotton, it has
great regain (when compressed, it springs back). With polyester fiber,
you can make a nice, tight plug that fits into the mouth of the vial. We
then submerge the vials preservative in a screw-cap jar with a good
closure (we use the flexible polypropylene lids that fit tightly to the
jar and do not unscrew themselves with temperature changes).  

Several entomologists have told me that their concerns with this system
are (1) the plugs coming out of the vials (I have never had this happen
if the plug is done right) and (2) they want to easily find the vial
they need without looking through a whole jar full of vials.  The latter
concern is easily solved by using smaller jars (3 or 10 or 20 vials per
jar, whatever) with a label indicating which vials are inside.  The
payoffs in security to the specimens and time saved in replacing
stoppers or retightening Bakelite lids when the temperature changes
cause them to unscrew or they crack from aging is well worth it (it is
worth noting that Bakelite is phenol-formaldehyde polymer that offgasses
formaldehyde as it ages).  

You can read more about this system and see a drawing in Conserve O Gram
11/4, available for free download from
http://www.nps.gov/history/museum/publications/conserveogram/cons_toc.ht
ml, or in "Herpetological Collecting and Collections Management" (SSAR,
2002).

--John

John E. Simmons

Collections Manager, Natural History Museum & Biodiversity Research
Center

and

Director, Museum Studies Program

University of Kansas

1345 Jayhawk Boulevard

Lawrence, Kansas 66045-7561

Telephone 785-864-4508

FAX 785-864-5335

jsimmons at ku.edu <mailto:jsimmons at ku.edu> 

www.nhm.ku.edu/herpetology <http://www.nhm.ku.edu/herpetology> 

www.ku.edu/~museumst

________________________________

From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Furth, David
Sent: Thursday, July 26, 2007 9:49 AM
To: mfobrien at umich.edu; bradh at rom.on.ca; Entomology Discussion List;
NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:3508] Re: Neoprene rubber stoppers

Bakelite (hard) is also not long-lasting.  Soft plastic tops with
polyethylene liners are much better

******************************************************

David G. Furth, Ph.D.

Department of Entomology

MRC 165, P.O. Box 37012

National Museum of Natural History

Smithsonian Institution

Washington, D. C. 20013-7012  USA

Phone: 202-633-0990

Fax: 202-786-2894

Email: furthd at si.edu

Website: www.entomology.si.edu 

________________________________

From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Mark O'Brien
Sent: Thursday, July 26, 2007 7:51 AM
To: bradh at rom.on.ca; Entomology Discussion List; NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:3505] Re: Neoprene rubber stoppers

Brad:

After having to replace about 70,000 gray EPDM  stoppers (sold by West,
and we should have sued them) and  3 dram vials in our collections with
4 dram vials with screwtop polyseal closures, I can tell you that rubber
stoppers of any kind are to be avoided.  Although the real neoprene
stoppers tend to have quite a long life, they are not archival, and they
do not always fit the vials properly, etc.  In our case, the EPDM
materials oxidized and the part exposed to the air melted after 15+
years of use.  My suggestion is to make the switch to the screw top
glass vials  and use bakelite tops with the polyseal cone liners.  M
Jacobs and Sons  in Detroit, MI sell them in bulk at a fraction of the
cost of places like VWR, etc.

Mark

---------------------
Mark F. O'Brien, Collections Manager
Insect Division, Museum of Zoology
2053 Ruthven Museums
University of Michigan, Ann Arbor, MI 48109-1079
734-647-2199
----------------------

On 7/25/07 10:54 AM, "Brad Hubley" <bradh at rom.on.ca> wrote:

Hi all;

I'm searching for a supplier of neoprene rubber stoppers for our glass
vials.  We used to purchase our stoppers from West Pharmaceutical but
have been told that they no longer supply them.  I have tried a number
of other sources (Plasticoid, VWR Scientific, BioQuip, etc.) but have
come up short, mainly because the length of our stoppers are what is
proving to be problematic.  The dimensions of our stoppers are 16 mm top
diameter x 12 mm bottom diameter x 20 mm length and the samples I have
been provided are 25 mm in length (or longer).  (If you need to see what
kind of stoppers I'm talking about then go to
http://www.vwrcanlab.com/catjpg/y01/y0155.jpg).  I'm concerned that if I
go with the longer stoppers, that the bottom of the stoppers will expand
in the vials over time making them almost impossible to get back into
the vials (we've encountered this on a regular basis with stoppers that
are pushed too far into vials).

If you have any suggestions as to suppliers, could you please let me
know?

Many thanks,
Brad

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
  Brad Hubley
  Entomology Collection Manager
  Department of Natural History
  Royal Ontario Museum
  100 Queen's Park, Toronto, Ontario           
  Canada    M5S 2C6

  Phone:  1-416-586-5764 
  FAX:      1-416-586-5553 
  email:  bradh at rom.on.ca 
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/nhcoll-l/attachments/20070726/b2348d0c/attachment.html 