[Nhcoll-l] glass jar with ground glass stopper

[Callomon,Paul]

As John points out, ground-glass jars can seal perfectly as they are. However, one problem is that each lid was originally ground to fit a specific jar - they came in pairs. Over the years, we have found that they can get mixed up, especially when they move across departments and collections. You can sometimes reunite them by feel, but often you will have a lid that is a very slight mismatch to the jar (it usually rides slightly low or high relative to the rim of the opening). In such cases, as long as the taper angle matches you can complete the seal with grease. We use Dow vacuum grease, which shows no signs of change or leakage after 25 years.


Paul Callomon
Collection Manager, Malacology and General Invertebrates

________________________________

Academy of Natural Sciences of Drexel University, Philadelphia
callomon at ansp.org<mailto:callomon at ansp.org> Tel 215-405-5096 - Fax 215-299-1170




________________________________
From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> on behalf of John E Simmons <simmons.johne at gmail.com>
Sent: Sunday, May 5, 2024 12:39 PM
To: Kathy Omura <komura at nhm.org>
Cc: nhcoll-l at mailman.yale.edu <nhcoll-l at mailman.yale.edu>
Subject: Re: [Nhcoll-l] glass jar with ground glass stopper


External.

Chances are that you do not need any grease at all on the seal. Before you add anything, you should check to see if the seal is good. To do this, first wash the jar and the lid with soap to remove any residue. Then fill the jar with 70% (no specimens) and insert the lid. Either mark the fluid level, weigh the jar + lid + contents, or both. After 24 hr (to give the lid time to settle) put the jar into a tub or sink that you can fill with water, starting at tap temperature, then gradually increasing until you reach the average temperature of your collection storage area (do NOT use very hot water, keep the temperature at what the jar will be subjected to in storage). You should know within a few days if it leaks or not.

When I was at the California Academy of Sciences we had thousands of similar jars in use. Most of the older ones had lids that were ground to fit the opening of the jar, which mean that if you got the right jar and lid combination, they did not leak, but if lids were switched around between jars, they often did.

If the jar does leak, follow Simon's advice and use Alsirol.


To remove these sorts of lids when they are stuck, try rocking the lid back and forth or tapping the handle part of the lid gently with a piece of wood, or gently tapping around the mouth of the jar (use a piece of wood and tap gently to avoid breaking the glass). If neither of those techniques works, you can put the jar in a sink, add warm water, and gradually increase the temperature until the internal jar pressure pushed the lid open--the drawback to this is that you will heat up the alcohol inside the jar which will speed up deterioration reactions in your specimens.

The other means to get the lids off is to purchase the Universal Stopper/Opener sold by Alcomon. The device is expensive, but works well:  https://alcomon.com/about/

--John

John E. Simmons
Writer and Museum Consultant
Museologica
and
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima


On Fri, May 3, 2024 at 4:09 PM Kathy Omura <komura at nhm.org<mailto:komura at nhm.org>> wrote:
I have not worked with these types of jars and was wondering what to use on the lids so they can be reopened. The jar will be holding a wet preserved (70% EtOH) specimen.
I heard vaseline on the ground glass part of the lid and jar makes it easier to reopen.
To make a tight seal, after the vaseline application, seal the lid with wax along the edge.
What other options do I have? I appreciate any help you can provide.
Kathy
--
Kathy Omura, Collection Manager
Marine Biodiversity Center
Natural History Museum of Los Angeles County
(213) 763-3386
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