I have not had the chance to follow this thread, but this e-mail from Peter made me think about my early years in shell collecting and the coating of shells with mineral oil.

Has it been mentioned that rather than thinning the oil--or what have you--with a solvent, etc., that it is very effective to warm the oil first?  I used to set up a double boiler. (A water-filled pan, upon which another pan was securely set.)  The water in the lower pan was brought to a boil, ensuring that the mineral oil or paraffin was heated to a safe, non-flammable temperature.  In fact, I would bring the water to boiling temperature, turn off the heat and add the mineral oil to the top pan to warm up.  In a cold room--I lived in New England--I kept the flame on low, rather than turn it off.  The warm oil was "thinner", penetrated better and did not leave a heavy coat, even on heavily textured shells.  I was always careful to not heat the oil too much, in order to not cook the colors or craze the shells.

I usually judged the readiness of the oil by stirring it with a wooden spoon--a good oil treatment for the spoon, and the oil's temperature was not lowered as much as a metal spoon would have done. Now I wish that I had taken temperature readings!  However, I believe that the oil never reached a temperature of even 160 degrees F before I dipped the shells.  The dipped shells cooled the oil, so I would add heat as needed.  The oil bath was on average of a depth of two inches (approximately 5cm)since the shells could be turned in the oil to coat.  When coating larger shells, like Busycon, I used deeper oil baths.  I did experiment with floating oil on hot water.  That worked rather well for the large shells: two inches of hot water and two inches of mineral oil.  Let things settle, then dip.

Shells that I collected and treated, from the early 1970s, are still colorful, and never gummy or degraded.

Hope this is helpfull.

Michael LaFosse
Origamido.com


--- On Thu, 5/21/09, Peter Egerton <[log in to unmask]> wrote:

> From: Peter Egerton <[log in to unmask]>
> Subject: [CONCH-L] coating shells...
> To: [log in to unmask]
> Date: Thursday, May 21, 2009, 8:39 PM
>
>
> Hi all,
>
>
> Thanks very much for all the answers to my questions about
> coating
> shells.
>
>
> I tried some mineral oil on some and didn't like the
> globbiness of the
> results (especially on non-porous shells).

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------