Tagged: @rleder @robertross @jkallmeyer
February 15, 2016 at 10:10 am #3315
Re-posting this topic on behalf of Case Miller (@case-miller) :
A couple months ago I was accepted to help clean fossils in a lab, and before I went in for the first time I decided to do a Google search on fossil preparation and see what it had to say, but I heard things within the first few minutes of entering the lab that hours of searching online didn’t yield, so I think this would be a good place to provide tips and tricks we’ve all found out over the years to help out people going in for the first time (and maybe even veterans!).
A few I’ve found thus far:
February 15, 2016 at 10:13 am #3316
- Water is usually the solvent I see recommended online to loosen the matrix around the fossil, but water can take a while to dry if, say, the specimen cracks and glue needs to be applied to a dry surface. Acetone (nail polish remover) dries much quicker, and thus works better in that respect.
- Another reason to use acetone: you can dissolve some glues in it (we use B-72, and while I know others will dissolve in it I’m not sure how they work), meaning you then have a liquid glue that can seep into cracks and pores and harden your fossil inside and out.
- Eyedroppers or just pouring the solvent works fine on large areas, but trying to get little areas wet can be done much more efficiently with a paintbrush; in fact, a soft, wet paintbrush can often dislodge stubborn matrix inside cracks of fossils that might crack under sturdier pressures (just make sure the solvent itself isn’t weakening the specimen if it happens to be porous). The same goes for dissolved glue, making sure you’re sealing up just the area you want, no more or less.
- The video tutorials do an excellent job of explaining how to make makeshift excavation tools, but I also wanted to highlight one thing I’ve found weirdly helpful: old dental instruments. If you have a dental school or office near you it might be worth it to as if they have any old or broken or otherwise unusable tools, as they’re designed to push apart softer material away from hard bone and allow you to feel the difference between the two really well as well as applying the pressure efficiently.
- And finally, the lesson I learned the hardest after destroying more than one fossil: when in doubt, magnify. The tutorials also give good instruction on how to rig up a makeshift magnifier (and if you already have a microscope all the better), but while they focus on using it to determine small details I find it essential for any final cleaning, as it allows you to see fractures and bends too small for the naked eye until they’ve already broken, and so instead you can glue them up before they’re a problem.
Re-posting Ronny’s response to Case’s original thread topic:
@case-miller Hey Case, Thank you for your comment and the idea of creating a forum about fossil cleaning etc. Maybe you have missed our video tutorials where we discuss some of this? I would like to invite you to have a look at these tutorials where we focus on many of these things. You can find them under “Resources.” We explain how to clean fossils, what instruments to use (dental instruments, tiny spatulas, etc.), and much more. Maybe you can help us improve our efforts in creating new video tutorials after you have watched what we already have? Thank you so much for your help!
all the best
RonnyFebruary 15, 2016 at 10:15 am #3317
Re-posting Case’s @case-miller response to Ronny:
I have indeed watched them, and they’re certainly helpful, but with all the different techniques required for different soils and fossil types I know no one would want to make or watch a video with every possible situation, so I thought a forum where individuals could search for mentions of things they’re working with would be helpful both from a creation standpoint, as it’s crowd-built and doesn’t require massive effort by any one party, and easier to find the exact information you want to get. The tutorials are an excellent starting place for someone diving in, I was thinking here would be a place for people who have started cleaning to come and see things that may work better than their techniques and hone their craft. It also can serve as a repository for information far too specific for an overview, e.g. someone has had years of experience cleaning fossil vertebrae and has found a tool to better see inside vertebral foramen; that’s far too specific to put in a tutorial, but still may be incredibly helpful to someone struggling with it.February 15, 2016 at 10:16 am #3318
Re-posting Ronny’s comment to Case:
Case, I think your idea is good and we should keep that forum for specific preparation and cleaning cases. For the general cleaning and preparation methods we will shoot some extra video tutorials. Thanks for your input.
RonnyFebruary 15, 2016 at 10:22 am #3319
This is John Christian’s @john-christian comment relating to this thread:
I like to soak my fossils in hydrogen peroxide (cheap at Walmart). After it has soaked awhile and the bubbles have helped to get rid of the clay and silt in the nooks and crannies, I brush the fossil with an old toothbrush.February 15, 2016 at 10:42 am #3322
Hey @john-christian, it also very important to let dry wet fossils and especially fossil containing sediment blocks before using hydrogen peroxide. That way the pore space is free of water and ready to soak the H2O2. Otherwise the pore space is kind of blocked and the H2O2 will not enter … . The drier the sediment block the better.
RonnyFebruary 15, 2016 at 10:48 am #3323
…. but be very careful with fragile fossils (like bigger mammal teeth) … the H2O2 is also able to destabilize and to open existing cracks that are naturally cemented. You should at least make some images of the fossils before H2O2 treatment. If bigger fossils break you may better be able to rearrange the fragments. It works best with very fine sediments like silt and clay, especially with marin sediments or swamp sediments.
RonnyFebruary 15, 2016 at 10:52 am #3324
… and if you are hunting for smaller fossils like shark teeth, shells or otoliths and the sediment blocks are quite big just crack them into smaller pieces (5 x 5 cm) and leave it in a H2O2 bath over night. Use a simple plastic bucket.February 22, 2016 at 2:54 pm #3341
The tutorials you did are good as is this forum. Everything I have seen here though is pretty much vertebrate related. Many of these techniques can be scaled down to apply to invertebrates but I find, at least here in the Cincinnatian, the techniques required are different. It is quite easy to damage or destroy a fossil in the cleaning process by using improper methods, improper materials or poor technique. One of the most important things we need to know when attempting to clean a fossil is when to stop. We also need to know what the matrix is made of and what the fossil is made of. Around here, both are primarily calcium carbonate precluding the use of acids for cleaning. Dental tools have been suggested for years and they are fine for rough cleaning but when you get close to the specimen surface they are too big and clunky. As you mention, magnification is a must and really fine cleaning requires a stereo microscope. Even in this area, different fossils require different cleaning techniques.
I am attaching two photos for your consideration. One photo is a crinoid that I hand cleaned with tiny pins and water – a technique I was taught by Prof Colin Sumrall of U of Tennessee when he was curator at the Cincinnati Museum years ago. The second photo is the same crinoid after a dusting with an air abrasive unit to remove the last film of dust. The original surface was completely filled in as you see at the top of the specimen. This process took many hours but the surface of the specimen is intact.
Would you recommend a separate forum for cleaning techniques for small invertebrates or do it all in this one?
Attachments:You must be logged in to view attached files.February 23, 2016 at 10:14 am #3344
Thanks for your comments. The recommendations I gave were multifarious and not just related to Vertebrates. In our cleaning tutorial I mentioned that cleaning methods are depending on matrix, fossil material and how fragile or stable your fossil is. I also cleaned a bivalve and gastropod shell and recommended some DIY advice for making even finer instruments like tiny spatulas for very delicate structures and tiny objects. I also pointed to specific tutorials about fossil preparation where I will focus on fragile objects, different fossil material and matrix. These tutorials are not finished yet. At the moment I am just about to finish the photo tutorial, then the one about preparation comes next. I do all this on top of my scientific work, and as you may understand it takes time. The preparation tutorial will also cover the use of different chemicals (different acids, H2O2, etc.), the use of sandblasters, Dremel tools, ultra sound bath and many more. The problem is that not everybody has the possibilities of using a sandblaster or an ultra sound. We have to be focused on techniques that everybody can use. I truly appreciate your helpful comments and I think it is a good idea to present your preparation techniques within this forum as a special section. Please do so. You can also create your own little tutorials and upload them if you like. That would be great!!!
I look forward for more input from you. Thanks!
all the best
RonnyFebruary 23, 2016 at 10:03 pm #3348
Sorry, it has been a while since I looked at the tutorials and I forgot all that you covered.
Since you brought up chemicals and their availability, I would like to see if you can source small quantities of a chemical that is used to disaggregate shale and mudstone. Many years ago a chemical known as Quatenary -O was used for this purpose. It was of a tarry consistency and had to be dissolved in hot water. Sometimes the fossils were actually boiled in this solution. The shale and mudstones coating fossils would literally fall off the fossils when soaked in this material. The commercial use for this chemical is in laundry detergents as they cause clay particles to disassociate. After this became unavailable, an amateur found another similar material that he sold as Rock Quat. This was a liquid that worked in the same way. This material is also no longer available. One of the U.C. grad students did some work in Germany and found another product there that was cheap and readily available called Rewoquat W3690. The Dry Dredgers tried to help him obtain this material here in the US but found it unavailable except in drum quantities for lots of money. If you are dealing with shales and mudstones these chemicals are close to miracle products. If you can help us obtain this product there would be a lot of happy people.
When the latest edition of the FOSSIL Newsletter comes out, there will be an article by Dry Dredgers Kyle Hartshorn. It is illustrated with my photos of edrioasteroids. All of these fossils except the last one were cleaned by soaking in Quatenary-O with only a little use of a toothbrush.
JackFebruary 24, 2016 at 10:13 am #3349
Hey Jack, no problem, like I said your comments help us to improve.
Now, regarding the chemicals you recommended and that are no longer available in the US… It is really funny because in my lab in Germany I have a huge container with Rewoquat and YES it is rather miraculous how it disassociates clay and silt. Strange that there is nothing similar in the US anymore. Maybe we can find a way to purchase a drum and bottle it in smaller portions. I will figure it out. Stay tuned …
all the best
RonnyMarch 5, 2016 at 11:01 pm #3378
As I kept thinking about our efforts to find Rewoquat W3690 I recalled more detail of the search that might be important to your efforts. We had a local distributor here in Cincinnati for this material. The UC grad students tried to obtain it through them but were told they would only sell to industrial customers – not universities!!! We asked our local Dry Dredgers member who owns a prep lab here if he could try. They would sell to him but only in drum quantities. This may not be of any help to you but I thought you should know the whole story.
JackMarch 6, 2016 at 7:07 pm #3381Matthew SpeightsParticipant
I started trying last year to contact the right person with Evonik (the company that produces Rewoquat) and order some. They finally got me in contact with a marketing manager in Virginia, who told me that Rewoquat was not available in the USA. However, they offered to send me a pint sample of Rewoquat W 3690 PG from Europe through the US division. So, I am awaiting the sample. I’m not sure how far it goes, but if I have extra, I wouldn’t mind sharing.
Long term, I would like to get more, so I also asked whether it might be possible for UC or the museum to order a larger quantity, and am waiting to hear back. If that simply isn’t possible, perhaps we could each ask for a sample. I really don’t want to ask for free handouts, though, and would like to purchase more if they’ll let us (a group buy would be a possibility I’d consider).
– MatthewMarch 8, 2016 at 8:56 pm #3388
Matt is working on the Rewoquat problem here too. He thinks he has a lead.
I know you said you have used this in Germany. The data for the product indicates it has a 12 month shelf life in a sealed container. What is your experience with this? Have you seen “old” material not work any longer?
JackMarch 9, 2016 at 5:37 am #3389
hey guys three minutes ago I just talked to the collection manager at the geological-paleontological collection at the University of Leipzig, and he told me that you can use Rewoquat after years of storage … no problem. It is just a combination of some tensides and there is no limited shelf life. He also will give me the address to purchase it for our needs.
All the best from Germany
RonnyMarch 10, 2016 at 6:37 pm #3404Matthew SpeightsParticipant
Good to hear, and thanks for looking into it. Evonik mailed me a sample of Rewoquat, and I should receive it tomorrow. Actually, it goes under a different name in the USA, but I’ve been told it is the same thing. I think it is of a different concentration, however, so I will test it before I recommend it.
– MatthewMarch 10, 2016 at 8:58 pm #3407
Can you tell us if Rewoquat is used full strength as received or diluted to some lower concentration?
JackMarch 10, 2016 at 9:45 pm #3408
Another question — what about disposal of used up Rewoquat? It is toxic to aquatic life. How is it handled in Germany?
JackMarch 10, 2016 at 9:49 pm #3409John ChristianModerator
Here’s an article which mentions the use of a 75% solution. There are also references to other articles that mention the use of Rewoquat. http://palaeo-electronica.org/content/2013/530-microfossil-extraction
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