[Nhcoll-l] To oil or not to oil?

Fri May 19 08:47:43 EDT 2017

>From many years ago I think I remember an amateur malacologist in the central USA advocating for use of a thin coating of something like a varnish or shellac to go on freshly dried unionid shells. Would this be considered acceptable? Would a modern reversible coating like Acryloid B-72 be advisable?
Thomas
Thomas E. Labedz, Collections Manager
Division of Zoology and Division of Botany
University of Nebraska State Museum
Lincoln, Nebraska, USA

From: nhcoll-l-bounces at mailman.yale.edu [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Paolo Viscardi
Sent: Friday, May 19, 2017 6:58 AM
To: Simon Moore
Cc: nhcoll-l at mailman.yale.edu
Subject: Re: [Nhcoll-l] To oil or not to oil?

Alternatively you could keep a sample of the oil with the specimens so that anyone taking samples for chemical analysis can also sample the oil and look for the chemical signature of the oil in their samples from the specimens and have a method of gauging and discounting the influence of the contaminant.

Paolo

On 19 May 2017 at 10:47, Simon Moore <couteaufin at btinternet.com<mailto:couteaufin at btinternet.com>> wrote:
This is somewhat dependent on whether the shells are to be displayed or not.  As Christian says, if you treat them, then molecular biologists may find them contaminated with chemicals.

However, I would urge that a few (the worst maybe?) could be treated to see how the periostracum responds and I would use Bollmann Ultra-Soft, normally used for mammal skins - but it has a host of other effective applications, and is available from WASCO.  Just brush a little on (shake the bottle first!) and see whether you get an overall improvement - the effect takes a few hours or overnight to take effect.

With all good wishes, Simon.

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian,
www.natural-history-conservation.com<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.natural-2Dhistory-2Dconservation.com&d=DwMF-g&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=dvKV-_JbQhLXKNkY4nR7Qr_U61VQE6FMy1P4RUavXdg&s=sjT2M5Q2AlhJIBkpc1uLF_kNKLuXpbsHjfAhhEbndAU&e=>

On 19 May 2017, at 10:27, Christian Baars <Christian.Baars at museumwales.ac.uk<mailto:Christian.Baars at museumwales.ac.uk>> wrote:

Paul,

What you describe almost appears to be a loss-loss situation: treat the shells and lose the potential for chemical analysis, don’t treat and lose the potential for morphological description.

I am no malacologist, but the beauty of this forum is that it brings together so many disciplines and perhaps I may be able to contribute from an ‘outsider’s’ point of view.

Various materials require different storage environments. For some collections it has been accepted for decades that it is impossible to keep all materials making up a complete collection in the same room under the same conditions. Think archaeology, excavated iron objects are so sensitive to corrosion under ‘normal’ museum store conditions that they are usually packaged in microenvironments at, ideally, <10% RH. We treat geological specimens containing ferrous sulphides in a similar way.

If your mollusc shells would benefit, i.e. suffer less damage, from being stored at higher RH, have you considered storing them in a microenvironment at high RH? We are in the fortunate position to have a naturally cool and damp room in the sub-basement of the museum building, where we have been storing a number of minerals (for example, polyhydrated sulphates) successfully (i.e. without any damage through dehydration) for several years. But you can also create microenvironments using saturated salt solutions (see, e.g., Greenspan 1977 https://urldefense.proofpoint.com/v2/url?u=http-3A__nvlpubs.nist.gov_nistpubs_jres_81A_jresv81An1p89-5FA1b.pdf&d=DwIGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=nk-Qz3SB9p7SLG6t5Mkk7alrv-9A_zEa6qgmJb4kGqU&s=V8_2rzbwOHHUy2Y_IsRNF5Gro-6TDCxv8NY2Qg_DbOg&e= <https://urldefense.proofpoint.com/v2/url?u=http-3A__nvlpubs.nist.gov_nistpubs_jres_81A_jresv81An1p89-5FA1b.pdf&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=r2Se_10ri0OGGh5AMJyd6j525aZxVXTjb91VjhmJEbE&e=>). There is a question of long-term maintenance, of course, as with any micro environmental storage. Another concern may be the potential for mould growth, and perhaps the potential for small salt deposits being precipitated on specimens. I have not tried it but it is on my to-do list to find some answers to these questions. If it worked for your shells you may have a way of preserving both morphological and chemical integrity of your specimens.

Kind regards
Christian

Christian Baars PhD AMA
Senior Preventive Conservator
National Museum Cardiff
Department of Collection Services
Cathays Park, Cardiff CF10 4NP, UK
Telephone: +44 (0)29 2057 3302<tel:+44%2029%202057%203302>
E-mail: christian.baars at museumwales.ac.uk<mailto:christian.baars at museumwales.ac.uk>
Twitter: @NMWPrevCons
Blog: https://urldefense.proofpoint.com/v2/url?u=http-3A__www.museumwales.ac.uk_blog_-3Fcat-3D2484&d=DwIGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=nk-Qz3SB9p7SLG6t5Mkk7alrv-9A_zEa6qgmJb4kGqU&s=1R5unpJyAK4lbkbgyC_BTwGrBlGzt0gbbXzgOiwmpxU&e= <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.museumwales.ac.uk_blog_-3Fcat-3D2484&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=J99x1LDnP1YF3_PDZ5Bd7KnXO91DDpB7djVp_TAu3Z4&e=>
https://urldefense.proofpoint.com/v2/url?u=https-3A__museum.wales_staff_643_Christian-2DBaars_&d=DwIGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=nk-Qz3SB9p7SLG6t5Mkk7alrv-9A_zEa6qgmJb4kGqU&s=nAgSmbIGRsY4xssQ8wd3CC-5uGOjbP0U20IiSDruh_I&e= <https://urldefense.proofpoint.com/v2/url?u=https-3A__museum.wales_staff_643_Christian-2DBaars_&d=DwMFAg&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=VKQZS6rxG5AJQtsXndEVaqcOUPV6kSpvLi_1WDMi92I&s=ZLCZJZZSEjP3XfhWT-9TjH2LFCkgZeeU_fHg6C3zO3g&e=>

From: nhcoll-l-bounces at mailman.yale.edu<mailto:nhcoll-l-bounces at mailman.yale.edu> [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Callomon,Paul
Sent: 18 May 2017 19:49
To: NH-COLL listserv (nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>) <nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>>
Subject: [Nhcoll-l] To oil or not to oil?

(This question is mainly for the managers of mollusk collections, but I’d like to hear from others who might encounter a similar quandary)

The shells of certain mollusks (almost all true mussels [Mytilidae]; pearl oysters [Pterioidea]; pen shells [Pinnidae] and many freshwater mussels) are composed mostly of nacre and have a thick, bonded periostracum. Removed from the water and placed in a dry environment, they begin to crack and split in a fairly short time. Their nacre can also decay, becoming powdery and weakening with time. The periostracum dries and hardens, and as its modulus of expansion differs from that of the shell, it begins to flake off or – in  the case of thinner shells – to crack the shell. Maintaining humidity at 45-60% year-round should slow this essentially evaporative process, but is unlikely to stop it.
A traditional technique to guard against all this is to coat the shells inside and out with a film of mineral oil (Petrolatum). This slows the escape of moisture from the shell matrix and keeps the periostracum somewhat flexible, and it certainly works; here at the Academy we have oiled freshwater mussel specimens dating back to the 1850s that remain entire. However, oiling is an additive technique and not fully reversible; detergents can remove the surface film but not purge the shell of oil entirely.
The debate, then, is as follows: On the one hand, adding a hydrocarbon to the shell might inhibit or preclude future chemical analysis techniques that we have not yet developed. On the other, a great deal of work in the mollusca (and many other groups) is based on morphology, and a tray of dust and fragments is of little use in that regard.

So: in your collection – to oil or not to oil?

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<mailto:callomon at ansp.org> Tel 215-405-5096<tel:(215)%20405-5096> - Fax 215-299-1170<tel:(215)%20299-1170>

YMWADIAD
Rydym yn croesawu gohebiaeth yn Gymraeg a Saesneg, ac yn sicrhau y byddwn yn cyfathrebu â chi yn eich iaith ddewisol, boed yn Gymraeg, Saesneg neu’r ddwy, dim ond i chi ein hysbysu. Ni fydd gohebu yn Gymraeg yn peri oedi.

Mae pob neges e-bost a anfonir at neu gan Amgueddfa Cymru yn cael ei
sganio gan systemau diogelwch awtomatig. Sganiwyd y neges hon am firysau cyn ei hanfon, ond dylech hefyd wirio bod y neges, a phob atodiad ynddi, yn rhydd o firysau cyn ei defnyddio. Nid ydym yn derbyn cyfrifoldeb am unrhyw golled neu ddifrod o ganlyniad i agor y neges neu unrhyw atodiadau. Gall y neges hon ac unrhyw ffeiliau a atodir ynddi gynnwys gwybodaeth gyfrinachol a fwriadwyd ar gyfer y derbynnydd yn unig. Os ydych chi wedi derbyn y neges trwy gamgymeriad, hysbyswch ni a dileu’r neges. Safbwyntiau personol yr awdur a fynegir yn y neges hon, ac nid ydynt o reidrwydd yn cynrychioli safbwyntiau Amgueddfa Cymru. Nid ydym yn derbyn cyfrifoldeb am unrhyw wallau, llygredd neu esgeulustod a allai godi wrth drosglwyddo'r neges hon.

DISCLAIMER

We welcome correspondence in Welsh and English, and we will ensure that we communicate with you in the language of your choice, whether that’s English, Welsh or both if you let us know which you prefer. Corresponding in Welsh will not lead to any delay.

E-mail to and from Amgueddfa Cymru is scanned by automated security systems. This message was scanned for viruses before transmission, but you should also satisfy yourself that the message, and all attachments, are virus-free before use. We can accept no responsibility for any loss or damage that might arise from opening the message or any attachments. This message and any files transmitted with it may contain confidential information intended only for the recipient. If you receive the message by mistake please inform us and delete it. The views expressed in this message are the personal views of the author and may not necessarily represent those of Amgueddfa Cymru. We accept no liability for any errors, corruption or omissions that might arise in transmission of this message.

________________________________

Scanned by FuseMail.
_______________________________________________
Nhcoll-l mailing list
Nhcoll-l at mailman.yale.edu<mailto:Nhcoll-l at mailman.yale.edu>
http://mailman.yale.edu/mailman/listinfo/nhcoll-l

_______________________________________________
NHCOLL-L is brought to you by the Society for the Preservation of
Natural History Collections (SPNHC), an international society whose
mission is to improve the preservation, conservation and management of
natural history collections to ensure their continuing value to
society. See https://urldefense.proofpoint.com/v2/url?u=http-3A__www.spnhc.org&d=DwIGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=nk-Qz3SB9p7SLG6t5Mkk7alrv-9A_zEa6qgmJb4kGqU&s=tJilgZuo25wOJYMX_sgbZS-E_pxqEFz8ABczTSI6Mu8&e= <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.spnhc.org_&d=DwMF-g&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=dvKV-_JbQhLXKNkY4nR7Qr_U61VQE6FMy1P4RUavXdg&s=Cm7-vyDa2il-TUqBdzb122jy4Bc3ouyf7PCN_VNLPss&e=> for membership information.
Advertising on NH-COLL-L is inappropriate.

_______________________________________________
Nhcoll-l mailing list
Nhcoll-l at mailman.yale.edu<mailto:Nhcoll-l at mailman.yale.edu>
http://mailman.yale.edu/mailman/listinfo/nhcoll-l

_______________________________________________
NHCOLL-L is brought to you by the Society for the Preservation of
Natural History Collections (SPNHC), an international society whose
mission is to improve the preservation, conservation and management of
natural history collections to ensure their continuing value to
society. See https://urldefense.proofpoint.com/v2/url?u=http-3A__www.spnhc.org&d=DwIGaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=nk-Qz3SB9p7SLG6t5Mkk7alrv-9A_zEa6qgmJb4kGqU&s=tJilgZuo25wOJYMX_sgbZS-E_pxqEFz8ABczTSI6Mu8&e= <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.spnhc.org&d=DwMFaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=CLFZJ3fvGSmDp7xK1dNZfh6uGV_h-8NVlo3fXNoRNzI&m=5g3iYypI9Nm0VQwoPqISwqabh4ig23JEVMRgwtZpyTo&s=V56vfuCdMDsaodgHzrTwKxRJh2hFaM6FRc7ULo4laHw&e=> for membership information.
Advertising on NH-COLL-L is inappropriate.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20170519/94563141/attachment.html 