OK, here's the problem. We're talking about two VERY different machines. My recent post concerned the ultrasonic wand used to remove placque from teeth, as demonstrated at the last COA. NOT the ultrasonic cleaner bath used by jewelry-type folks. I think Paul's comments were about the latter, given his discussion of a tank, which doesn't exist with the wand.

G.Thomas Watters, PhD
Curator of Molluscs
Department of Evolution, Ecology & Organismal Biology
The Ohio State University
1315 Kinnear Rd.
Columbus, OH 43212  USA
v: 614-292-6170
f: 614-292-7774

----- Original Message -----
From: "Monfils, Paul" <[log in to unmask]>
Date: Tuesday, February 6, 2007 3:17 pm
Subject: Re: RES: ultrasonic scalers for shell cleaning

> A few comments on Tom's comments ...
>
> Although I have not noticed a case of the ultrasonic cleaner (UC)
> directly damaging a shell, it will break loose any portions that
> are already loosened. If you have a thin shell that has a hairline
> crack in it, the water in the UC will penetrate the crack and the
> sonication action will expand it, in some cases breaking the shell
> - but actually the shell was already "broken" before sonication.
> Likewise if there is a small hairline crack in the lip, sonication
> will cause the chip to separate and fall out, but I have never
> seen an intact lip chipped by sonication, even on a Hydatina or
> Haminoea. I'm rather surprised at what happened to the Cittarium,
> having cleaned hundreds of trochids with the UC, and I strongly
> suspect that this shell may have had the outer layer already
> separated from the underlying layers either by freezing of the
> specimen or by too rapid heating (dropping into boiling water for
> example, or microwaving). In that case sonication would certainly
> finish the job.
>
> The UC, especially if it is a fairly high wattage unit, will cause
> small shells to zip around the bottom of the tub, and some damage
> can occur from collisions between shells. In a high speed
> collision between a Columbella and a Haminoea, the Haminoea is
> going to lose every time. This can be prevented by wrapping
> fragile shells loosly in cotton or glass wool, placing them inside
> a protective container such as a small plastic box or a 35 mm film
> canister, filling the container with water, and immersing it in
> the UC. The ultrasound waves will pass right through the wall of
> the small container and clean whatever is inside it, but the
> object will be gently held in position so it can't scoot around
> and make contact with other items or with the walls of the tub itself.
>
>

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