I fully agree.  Not being an expert, but an outside of a box person -
think on some of this - has dryers, and solvents.  All hydrocarbon based
and what does it do to color and is it absorbed below the surface.

Martin

Paul Callomon wrote:
> I've seen clear silicone (usually the stuff that is sold as a spray-on
> mold release agent for fiberglass molding) used on shells with no
> apparent wet residue. I wonder whether it does wash off though. For
> something that is specifically used because it's slippery and doesn't
> stick, silicon can be a bear to get off things. I doubt whether it
> preserves periostracum in any permanent way, either, as it has no
> modulus of its own (it's thin and watery), unlike for example paraffin
> oil, which is far heavier than any of the light aromatic fractions
> like kerosene or gasoline.
> Someone mentioned Armor-All. I would not use that on shells for the
> same reason as was advanced against WD-40 - you don't know what's in
> it. I'd not be surprised if Armor-All had some Carnauba or similar wax
> in it, which would explain the slight sheen it leaves even when the
> aromatic part has evaporated.
>
> PC.
>
>
> Paul Callomon
> Collections Manager
> Malacology, Invertebrate Paleontology and General Invertebrates
> Department of Malacology
> Academy of Natural Sciences
> 1900 Parkway, Philadelphia PA 19103-1195, USA
> Tel 215-405-5096
> Fax 215-299-1170
> Secretary, American Malacological Society
> On the web at www.malacological.org
>
> >>> Phil Poland 05/16/09 11:20 AM >>>
> Silicon oil, either in pure form or the emulsion (ArmorAll), was
> suggested to me as a means of reducing scuffing and oxidation.
> Periostracum is preserved and color loss seems to be slowed. I assume
> that the barrier provided by the silicon oil is far greater than
> the simple surface area, the shell being somewhat porous. Not only is
> the shell more attractive, but isn't greasy to the touch and washes
> off easily.
> Is there a long-term risk that I wouldn't like? How far back do
> silicon oil applications go?
>
> Phil
>
>     ----- Original Message -----
>     *From:* Paul Callomon <mailto:[log in to unmask]>
>     *To:* [log in to unmask] <mailto:[log in to unmask]>
>     *Sent:* Saturday, May 16, 2009 08:30
>     *Subject:* Re: [CONCH-L] oil and alcohol
>
>     Here at the museum, we often get shells in collections that have
>     been oiled. Depending on what has been used, it's more or less
>     easy to remove it, and in most cases we do as the coating serves
>     no useful purpose and all oils will degrade in time. However, some
>     of our antique unionids date back to the 1860s and are mostly in
>     good shape because they were painted with paraffin. When you open
>     their cabinets, the smell of oil is still very strong. On the
>     other hand, I cataloged a Crenomytilus the other day that I had
>     collected in Russia in 1995, and it had split almost in two. Oil
>     probably would have prevented that.
>     So: for a museum, it makes sense to oil some specimens (or immerse
>     them in glycerine) if the alternative is their disintegration.
>     This also true for thin-shelled things with thick periostracums.
>     The expansion/contraction rates of the two substances are quite
>     different, and that can cause the shell to crack up (Paryphanta
>     snails and abyssal buccinids are good examples).
>     If there's no reason other than brightening up the color, however,
>     we avoid any kind of coating. Most oils will oxidise, thicken up
>     and turn to sticky gum in time, often darkening the shell anyway.
>
>     PC.
>
>     Paul Callomon
>     Collections Manager
>     Malacology, Invertebrate Paleontology and General Invertebrates
>     Department of Malacology
>     Academy of Natural Sciences
>     1900 Parkway, Philadelphia PA 19103-1195, USA
>     Tel 215-405-5096
>     Fax 215-299-1170
>     Secretary, American Malacological Society
>     On the web at www.malacological.org
>

--
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/

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