[Nhcoll-l] Opening specimen jars with jammed ground glass stoppers?

[Dirk Neumann]

Dear Truth,

the stoppers that are self-sealed and jammed can be opened by putting 
them under the tap and let hot water (approx. 40-50 °C) run on the 
stopper / neck of the jar. In case you have external labels attached to 
the outside of the jar, it is worth testing if they peel of or the ink 
starts bleeding (ah, Paul was faster with his reply :-)

The hot water widens the neck (expansion of the glass) while inside the 
jar the trapped gases expand and increase the internal pressure - be 
aware that up to 2bar of more could build up inside alcohol filled jars 
causing the jammed stopper to rocket-off in rare cases.

Silicone glued jars are more delicate. If the silicone is thick enough, 
you can use a sharp pointed knife to cut the glue between stopper and 
neck; never tried this in stoppered jars, in flanged jars you could 
carefully cut the lid of with sharp blades like scalpel, sharpened 
palette-knifes. There might be some chemical agents which could remove 
the silicone, but the issue here is that these may contaminate the 
holding fluid.

Hope this helps
Dirk


Am 15.10.2019 um 21:45 schrieb Truth Muller:
> Hello,
>
> I am currently one of a small team of students from College of the 
> Atlantic doing extensive restoration work on the George B. Dorr 
> Natural History Museum collections. We are preparing the entirety of 
> the Museum's collections to be moved to a new, modern storage facility 
> which is still under construction.
>
> I am responsible for the Ichthyological and Marine Invertebrates wet 
> collections, which have unfortunately suffered from neglect over the 
> past 10-15 years. Only about 60-70% of the Ichthyological collection 
> specimens are in modern jars with screw-top lids, and the rest are in 
> e in much older jars with ground glass stoppers. Some of them are 
> sealed with silicone, a few with an unidentified wax, and others have 
> simply self-sealed with their own fluids congealing between the jar 
> and the stopper. Many of these jars need to be topped off, and a few 
> are cracked and urgently need to be replaced, but almost every single 
> stopper is stuck fast as though super-glued. We have not yet found a 
> way to open them without putting the specimens inside in harm's way.
>
> What is the best method that we can use to open these jammed jars, 
> preserving the specimen, and, ideally, the jars as well? Any help or 
> advice would be greatly appreciated!
>
> ~Truth Muller
> George B. Dorr Museum of Natural History
> College of the Atlantic '21
>
>
>
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-- 
Dirk Neumann

Tel: 089 / 8107-111
Fax: 089 / 8107-300
*new email: neumann(a)snsb.de*

Postanschrift:

Staatliche Naturwissenschaftliche Sammlungen Bayerns
Zoologische Staatssammlung München
Dirk Neumann, Sektion Ichthyologie / DNA-Storage
Münchhausenstr. 21
81247 München

Besuchen Sie unsere Sammlung:
http://www.zsm.mwn.de/sektion/ichthyologie-home/

---------

Dirk Neumann

Tel: +49-89-8107-111
Fax: +49-89-8107-300
*new email: neumann(a)snsb.de*

postal address:

Bavarian Natural History Collections
The Bavarian State Collection of Zoology
Dirk Neumann, Section Ichthyology / DNA-Storage
Muenchhausenstr. 21
81247 Munich (Germany)

Visit our section at:
http://www.zsm.mwn.de/sektion/ichthyologie-home/



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