How should I go about this echinoid prep?

[MrBones]

I am new to fossil preparation, I really want to prepare this echinoid I found on Jebel Hafeet, Al Ain, UAE. 

I have started prepping it with a small needle, since I don't have access to any fancy machines, but I think I just ended up damaging the fossil. The rock seems to be a type of clay, not too hard. It might also be limestone, since the area is known for its shallow marine sedimentary rocks. Should I soak it in water? Or vinegar? Should I have a go at it with my dremel?

[Huntonia]

I'm not entirely sure how best to go about this. Could you add some close ups of the areas you've tried to prep manually? I'm not sure with echinoids but in general vinegar is not very recommended for safe fossil prep. Looking at this piece some consolidating might be the best place to start. Let's see what the experts say.

[Coco]

The matrix seems to be limestone, which means that your sea urchin is calcite, a mineral that reacts to all acids. So vinegar is totally banned, under penalty of "eating" your sea urchin.

 

Where is UAE ? We are many members of this forum who are not American.

 

Coco

[MrBones]

12 minutes ago, Coco said:

The matrix seems to be limestone, which means that your sea urchin is calcite, a mineral that reacts to all acids. So vinegar is totally banned, under penalty of "eating" your sea urchin.

 

Where is UAE ? We are many members of this forum who are not American.

 

Coco

This little echinoid is certainly off the menu! Thanks for the advice. For those who didn't know UAE stands for United Arab Emirates, it's in the Middle East. I'll try to post some closeups of the preparation marks.

[MrBones]

The matrix is very "sticky".

[Ludwigia]

Of course the best method to remove the matrix from this echinoid would be to use an air abrader, but since you don't have access to one, you would have to continue on with needles and other scraping tools. You could also try out your dremel. Another method is to scrub it briskly under running water with a metal brush. You schould check it every once in a while to make sure that the shell remains stable. If it seems to be loosening up, then you should let liquid super glue run into the cracks. Too bad that some shell is already missing at the tip, but maybe the back side is ok.

[MrBones]

4 minutes ago, Ludwigia said:

Of course the best method to remove the matrix from this echinoid would be to use an air abrader, but since you don't have access to one, you would have to continue on with needles and other scraping tools. You could also try out your dremel. Another method is to scrub it briskly under running water with a metal brush. You schould check it every once in a while to make sure that the shell remains stable. If it seems to be loosening up, then you should let liquid super glue run into the cracks. Too bad that some shell is already missing at the tip, but maybe the back side is ok.

Thanks! Unfortunately only the top half remains, you can see the cross section on the underside. I have recently bought some paraloid b72, so I'll test it out on this echinoid.

[Phevo]

Removing the majority with a pinvise/dentist tooth picks and then for the direct contact with the urchin, try applying some water and brushing with a toothbrush where the brushes have been cut down to 2-3mm long so that it is stiff.

 

I have used that technique on echinoids from Denmark in moderate hard limestone, looking at the last picture it looks relatively soft, but I have not prepped anything from Jebel Hafeet though I do have a few echinoids from there. 

 

I have seen echinoids prepped with a wire brush dremel/grinder and it will leave big marks/scratches since the calcium of the echinoids is relatively soft compared to the wire brush, so I think that should be a last resort

 

 

[MrBones]

3 hours ago, Phevo said:

Removing the majority with a pinvise/dentist tooth picks and then for the direct contact with the urchin, try applying some water and brushing with a toothbrush where the brushes have been cut down to 2-3mm long so that it is stiff.

 

I have used that technique on echinoids from Denmark in moderate hard limestone, looking at the last picture it looks relatively soft, but I have not prepped anything from Jebel Hafeet though I do have a few echinoids from there. 

 

I have seen echinoids prepped with a wire brush dremel/grinder and it will leave big marks/scratches since the calcium of the echinoids is relatively soft compared to the wire brush, so I think that should be a last resort

 

 

Thank you! I am definitely going to use an old "modified" toothbrush. So far I have only removed some surrounding matrix, I'll have to consolidate the matrix on the underside before working on it further, because it is cracking.

[Ptychodus04]

The prep method I’m about to describe is dangerous both for you and your fossils. I can’t state any clearer that I DO NOT recommend anyone use this method ever.

 

That being said, it works if done right. 
 

First, get all the proper PPE such as rubber gloves, face shield, goggles, and respirator. Then  get yourself a bowl of baking soda. Fill a bucket with water and pour a small amount of muriatic acid (25% hydrochloric) into a non reactive dish (glass or plastic). The baking soda is in case you spill some acid. This stuff will etch concrete, metal, you, and your fossils. 
 

As I said before, don’t do this.

 

After one has removed most of the matrix and there’s only the stubborn bits left, take a toothbrush and dip it barely into the acid. The trick is to barely wet a few bristles. Touch this to an area of matrix (not the fossil itself). It will immediately foam up, dunk your fossil immediately into the water. You will have removed a minuscule amount of matrix. Repeat this process until all the matrix is gone. It will take a long time but if done right, you won’t damage the fossil. When done soak the fossil for a few hours in fresh water with a couple tablespoons of baking soda to neutralize the acid.

 

What not to do:

 

Don’t soak the fossil in strong acid.

Don’t scrub the fossil with the acid soaked brush.

Don’t do this wearing clothes you like.

Don’t do this wearing shorts, short sleeves, or flip flops.

Don’t do this inside.

Don’t do this on your driveway.

 

And most importantly, don’t use this prep method. It is shared here only for educational and hypothetical purposes.

[MrBones]

7 hours ago, Ptychodus04 said:

The prep method I’m about to describe is dangerous both for you and your fossils. I can’t state any clearer that I DO NOT recommend anyone use this method ever.

 

That being said, it works if done right. 
 

First, get all the proper PPE such as rubber gloves, face shield, goggles, and respirator. Then  get yourself a bowl of baking soda. Fill a bucket with water and pour a small amount of muriatic acid (25% hydrochloric) into a non reactive dish (glass or plastic). The baking soda is in case you spill some acid. This stuff will etch concrete, metal, you, and your fossils. 
 

As I said before, don’t do this.

 

After one has removed most of the matrix and there’s only the stubborn bits left, take a toothbrush and dip it barely into the acid. The trick is to barely wet a few bristles. Touch this to an area of matrix (not the fossil itself). It will immediately foam up, dunk your fossil immediately into the water. You will have removed a minuscule amount of matrix. Repeat this process until all the matrix is gone. It will take a long time but if done right, you won’t damage the fossil. When done soak the fossil for a few hours in fresh water with a couple tablespoons of baking soda to neutralize the acid.

 

What not to do:

 

Don’t soak the fossil in strong acid.

Don’t scrub the fossil with the acid soaked brush.

Don’t do this wearing clothes you like.

Don’t do this wearing shorts, short sleeves, or flip flops.

Don’t do this inside.

Don’t do this on your driveway.

 

And most importantly, don’t use this prep method. It is shared here only for educational and hypothetical purposes.

Sounds very interesting, I would like to see someone else do this. I bet half of the ingredients are banned or restricted in this country, so I won't be doing this, fortunately.

[Ptychodus04]

The acid is the only thing that is “dangerous” but it is commonly used in swimming pool treatment here to lower the PH of the water if needed.

 

It’s a good way to mess up all kinds of stuff if you’re not used to handling acids.

[MrBones]

Here's a quick update on the prep. I've been using the "modified toothbrush" technique, it's very time consuming, but strangely satisfying.