Show your acid prepping results!

[Jaybot]

Like the title states, let's see your results with acid prepping!

I have found not as much info on this style of prepping, so please feel free to give some details as to how it was done, i.e. time, technique, soak sessions, etc.  

 

Have a great day everyone~

[Ludwigia]

This style of prepping isn't used all that often, since most fossils are preserved in calcite, aragonite or other substances which would be dissolved. The only fossils where I used a 5% hydrochloric acid bath were silicified corals enclosed in limestone. Depending on the amount of limestone to be dissolved, you had to moniter the process regularly and then give the fossils a long bath in soapy water or some other basal solution when finished in order to neutralize any leftover residues and then rinse them finally with clear distilled water. Of course the usual safety precautions need to be followed.

[Fossildude19]

Not a fan of the acid prepping.

Doesn't work well on the fossils I find. Tends to destroy the fossils, rather than reveal them. 

I know there are a number of videos on Youtube about it. 

 

[Ptychodus04]

I'll try to put some of my micro teeth under the microscope and take some pictures. I've used acid preparation many times on clients' fossils but have no photos of them. For my purposes, I use 5% acetic to dissolve limestone matrix that is full of microscopic ray and sawfish teeth. It takes around a month to dissolve a small piece of limestone (1/4" thick and no more than 2" diameter).  Once it is completely dissolved, I soak what's left in water for a month, changing the water weekly. Then, I let it dry and pick the teeth out using jewelers' tweezers.

[Jaybot]

I agree with you all on how acid prepping doesn't really work 90% of the time, which is why I started this thread; was curious as to the successful applications of this method 😉

Thank you everyone for your replies and insight!

[hadrosauridae]

I have played with it on some Cretaceous echinoids from the Duck creek fm.  I used standard 5% acetic in very short soaks about 2 -3 minutes followed by about 30 minutes in fresh water, then drying, then air abrasion.  It works really well but is extremely slow.  If you forget and leave one in for half an hour, it will noticeably eat the outer shell, so you cant get distracted.  You need to coat all the exposed fossil with a Paraloid / Butvar type consolidate to protect it before each bath.  I don't have any pics from my experiments with it.  

[Harry Pristis]

I'm not very interested in, or knowledgeable about, acid prep, but here are some results.  I used straight muriatic acid on a softball-size chunk of limestone from the Glass Mtns in West Texas.  I refreshed the acid when it seemed to stop working (neutralized).  I did this outdoors.  This was an experiment with a "rock" I brought back from Texas; I simply was curious to see what it contained.  I later sifted through the residuum to recover these.  I didn't bother with micros.

[Jaybot]

7 hours ago, Harry Pristis said:

I'm not very interested in, or knowledgeable about, acid prep, but here are some results.  I used straight muriatic acid on a softball-size chunk of limestone from the Glass Mtns in West Texas.  I refreshed the acid when it seemed to stop working (neutralized).  I did this outdoors.  This was an experiment with a "rock" I brought back from Texas; I simply was curious to see what it contained.  I later sifted through the residuum to recover these.  I didn't bother with micros.

Wow, great results.  Are those fossils silicified?  Cool to see a brachipod with the spines still attached.  I find a similar species, and it kills me to scribe right through those.

[Harry Pristis]

1 hour ago, Jaybot said:

Wow, great results.  Are those fossils silicified?  Cool to see a brachipod with the spines still attached.  I find a similar species, and it kills me to scribe right through those.

I think they're called the "Glass Mountains" because of the silicified fossils that, when exposed at the limestone surface, are like shards of glass.  I read about these fossils before my trip to Texas.  It turned out that the Glass Mtns are all on private property, and difficult to access.  

[Ludwigia]

I mentioned above that I had also prepped some silicified corals. They were found buried in limestone on a plowed field near Stuttgart. Here are a couple of samples.

 

Placophyllia rugosa

 

Plesiosmilia spatiosum

 

[Jaybot]

15 hours ago, Ludwigia said:

I mentioned above that I had also prepped some silicified corals. They were found buried in limestone on a plowed field near Stuttgart. Here are a couple of samples.

 

Placophyllia rugosa

 

Plesiosmilia spatiosum

 

Now there is something that acid prepping can achieve whereas other methods can't.  The extracted detail is very impressive.  Thank you for sharing!