Pointers On How Best To Prep This Fish Material? Or Should I Just Leave It As Is?

[claire01]

I found this little fish recently and was wondering if someone could give me some advice on prepping it. It's very small- 3" x 2" . The matrix is moderately hard and some of the bones are very tiny and delicate looking. Should I just leave it as is? Thanks in advance for any advice

Cretaceous, Eagle Ford.

[snolly50]

Wow, that would appear to be a challenge. Certainly not as straight-forward a task as the Green River material with which I am familiar. From the position of the visible verts it would seem very disarticulated, I don't think prep will reveal a "whole fish," but rather more parts of the critter could be exposed.

If it were mine - I would start with a carbide needle under a Zoomscope and try working the matrix around some of the delicate ribs. This will allow you to judge the relative strength of the fossil vs matrix. If successful (exposing more bone without wrecking it) I would just work out from the already exposed material in a search. I suspect just more "parts," but it's possible that some articulated sections will appear.

I suspect folks with air abrasive experience may voice a different approach.

It is a wonderful thing just as it is, but if it were mine I could not resist at least trying to expose more. Good luck and most of all have fun.

[Taogan]

Nice specimen, even though the fish is disarticulated. Looking at the back there might be bones all the way through the rock, any prepping would just bring out a few more, but not a whole fish. You might want to try an acid bath to bring out more detail on the the visible bones and leave it at that or try the same idea with an air abrasive, I suspect that anything else would damage the smaller bones.

[Uncle Siphuncle]

air scribe and a very light touch

[claire01]

Thanks, y'all. I've taken this out to work on it multiple times, then just ended up putting it away again because I could decide what the best approach would be.

[fossilized6s]

I would start with the verts and larger chunks. Personally there's not much more you can uncover with the ribs, so i wouldn't touch em'. But make a nice border around the ribs (1/4" or so) and maybe probe deeper into the rock to possibly uncover more of your specimen. It may prove to be easier for you to use a pencil to make the borders.

Good luck!

[jpc]

Looks to me like a job that requires a microscope and a supply of glue of some sort. Very sharp needles also a must. And a ton of patience.

[Ptychodus04]

Claire,

I've been prepping tons of Eagle Ford material for the last 20 years or so as it is one of my local formations. It looks like it is in one of the hard mudstone concretions. If that's the case, the outside should be fairly "soft" but about 1/16"-1/8" deep it will be hard as concrete! I've had good luck starting with needles on the softer material and moving to the air scribe to get after the hard stuff.

Vinegar and the usual acetic or formic acids won't touch the stuff. You can use local application of sulfuric acid, but be VERY careful. It won't discriminate between matrix, fossil bone, or your skin in any way. Safety, safety, safety. This stuff is bad news. But, I have had good luck with it. In a well ventilated area (read outdoors), drop a small drop of acid on the matrix next to the bone and let it sit for a few seconds. Then rinse it with water and scrub with a tooth brush. Repeat this about a million times and you will have quite a nice specimen. Don't rush the process and make sure to keep as much acid off the fossil as possible. Coat the exposed bones with Vinac or Butvar to protect them from the acid. The coating will turn white but will easily remove with acetone after the process is complete.

Send pictures of your progress next summer! It will probably take that long...

[claire01]

That is exactly what I have experienced! I don't know how many half prepped fossils I have given up on after exactly what you described. I bought an inexpensive engraver, but found I did more harm than good with it and put it away after losing part of a claw on a crab fossil I was particularly fond of. I have resisted using strong acids but now may give it a try. I'm so glad you posted this! I thought it was something I was doing wrong

[Ptychodus04]

That's the joy of prepping Eagle Ford fossils. The matrix is either diamond hard concretions or butter soft shale! Either way, prepping is a pain!

Don't give up on the mechanical prep. Work on some junk fossils and you will learn when to stop... usually! I still bust off a piece every now and then. The trick is finding it and gluing it back on! When funding allows, consider stepping up to a pneumatic scribe. I use an Aro and it is great for most small to medium work. My it's expensive but I think every preparator would agree that the added control and tighter mechanical tolerances are well worth the investment. My prep went to a whole different level when I stepped it up.

Keep it up.