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We had a question from @carl-lewis on our YouTube account: what are the best chemicals to use to prepare trilobites in limestone?
@jkallmeyer any ideas?
@sadie-mills @carl-lewis A lot depends on the preservation material for the trilobite. Most will be calcitic and will be adversely affected by any chemical cleaner that will dissolve limestone. To remove loose or soft shale or mud a toothbrush with water and an optional mild detergent will help. If the limestone matrix is covering part of the trilobite there is no free lunch . . . air scribes and air abrasive cleaning by an expert preparator are required. Inexperienced use of these tools can ruin a fossil in the blink of an eye.
What air scribe would you recommend for home use, @JKallmeyer?
@samantha-ocon I am sorry I can’t offer any help along those lines. I don’t use this type of equipment as it isn’t generally needed for most fossils around here. “hard core” people who do lots of this type of work are the ones who use these. If you do get one of these remember that you still need a strong suction device pulling away the material so you don’t breath the fines. These fines can cause lung damage even many years in the future.
Jack
@samantha-ocon I could check to see what they use in the Cincinnati Museum prep labs. Maybe that will help. I am laid up with a foot injury so I’ll have to get one of my friends to check.
Jack
@samantha-ocon , @sadie-mills I have an answer for you. I got the following information from one of the prep lab people who actually use these tools:
The normal tool we use is Chicago Pneumatic scribe which comes in any number of sizes depending on what you want to use it for. Paleo Tools has a wide selection of the Chicago and also services them. We have a coarse one for removing bulk matrix and a finer tipped one for finer work. Invertebrate paleo has some new tools that they call “German” which are Universal Tool air scribes UT8617. I was told they were around $900 apiece but online I see them listed for around $255. The Chicago runs around the same.
I hope this helps
Jack
Thank you, @jkallmeyer, for investigating this! Hope your foot improves!
There are actually quite a few options in terms of air scribes and they vary in power (matrix removal rate). The Chicago Pneumatic (CP) 9361 is quite powerful and may be more than a typical home hobbyist might want. Below that in terms of power but with finer detail is the Aro air scribe. It is also available as a specially modified version for fossil prep work under the Paleo Aro label. Generally, most hobbyists will want to use a CP 9361 to remove excess matrix, then the Aro to do finer detail work. An air eraser using abrasives can then be used as a finishing step to reveal fine surface details. I get by with just a Paleo Aro and a dental sandblaster cabinet. The same manufacturer that makes the Paleo Aro makes even more powerful tools called the Mighty Jack and Super Jack. For finer detail than the Aro and for microscope work, they make the Micro Jack in 6 sizes, with 1 being the finest. Generally, these are reserved for professional labs due to the expense and specialized applications.
Before embarking on any physical prep work, I would highly recommend having a consolidant such as Acryloid/Paraloid B72 in a 5% solution handy to stabilize the fossil before and as you go. Otherwise, its likely you’ll start blowing away chunks of the fossil.
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