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Thecosmilia Trichitoma

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Thecosmilia Trichitoma

I got two unprepared GRF fossil fish, a Knightia and a Priscacara as presents for my birthday, in a kit that also contained a small handheld needle-like tool. I would like to get some advice from the experienced members of this forum on how to proceed. For tools, I have a sewing needle, x-acto knife (with parental permission,) and the tool that came with the kit. I have a slides microscope that can focus well enough for a prep in order to have some magnification. I have Lance Grande's book on the GRF for anatomy, and have read all of the prep threads I could find on this forum. I have decided to start on the most exposed part of the backbone, and move up from there, saving the delicate fins for last. I have already tried out the tools on a few coprolites and vertebra on the rock. What advice do you have for this prep to be as successful as possible? @RJB @Ptychodus04 ? Thanks!

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First, welcome to the land of fossil prepping. 

The best advice I can give is to take it slow. Don’t get in a hurry and you make less mistakes. Also, expect to make mistakes. They will happen, don’t beat yourself up when they do.


You can use a dampened sponge to moisten the matrix slightly. This will soften it further but be sure not to soak it and don’t get the fish wet as it will soften the fish as well. 

Get some Paraloid B72 online and dissolve approximately 1 part Paraloid to 50 parts acetone by weight. You can also measure 1 heaping teaspoon into 1 cup of acetone for a similar mix. Using a fine artist’s paintbrush, paint the solution onto the exposed (and dry) fish. This will keep it from falling off as you prep.


Good luck and have fun.

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As you will be using non-powered (well except by you) tools, remain mindful of strain to your hands. The small, repetitive motions required for the task can easily cause painful results and disrupt your progress; if caution is not exercised. It is far too likely an occurrence to become engrossed in the activity and lose track of how long you have been working. Schedule breaks. Lung and eye protection are also considerations. For the type of prep you are doing, the hazard is perhaps small. However, remain mindful of potential danger and evaluate the need for protective measures. I am not exactly clear what you mean by a "slides microscope." If you mean a rig with a stage designed to hold glass slides for viewing, i believe it will be of little utility for your task. An optivisor or a free-standing magnifier will be more helpful. With young eyes, you may not need magnification at all. It might be helpful for you to post a picture of your pieces. In that manner, folks can get a better idea of what Green River matrix you are facing. 18" layer requires different methods/techniques as opposed to the split fish layer.

Good luck, most of all have fun 

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It is better to do a good job slowly than a bad job fastly.  That is my basic prep advice to anyone.  


The others have offered good advice.  One cheap addition you can make to your toolbox is a Poofer.  Basically a small rubber bulb that blows air so you don't have to constantly bow the powdered rock off your specimen.  This can be a lens cleaning bulb with the brush removed from the photo store, but better yet, bath toys come in all sorts of fun animal shapes.  I have seen folks use a straw, but when I tried it, I ended up getting saliva in the straw and ... well, yuk. 


See this for an idea... this one says you can buy 10,000 of them at once.  Have fun.  


If it will spray water, it will blow air.  

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