Newbie needing guidance regarding green river fish prep

[kmmerwick]

Hi,

I'm prepping green river fish fossil scraps.  When I get down to skin/scale tissue it becomes softer and oilier.  I'm using a pinvise and on areas like these and the usual gentle scraping has little effect.  I'm not sure how to approach this material without damaging it.  I'd love some input on how to proceed.  Also, it seems like oil begins to permeate and darken partially scraped areas over several hours ie: backbone.  Is there a special way to store the pieces in between prep sessions?

 

Thanks in advance-

K

[Fossildude19]

@Ptychodus04  @RJB

[RJB]

As for prepping the GRF fish, your going to lose fish material no matter what.  If something is loose, you can use what I call the "stop and glue" technique to help keep it in place and not lose it.  As to what you are calling 'oilier', I have never experienced this so not sure what to tell you about that.  Do you have any pictures to help out with that issue?

 

RB

[jpc]

Are you practicing on split fish or 18 inch layer?

 

[hadrosauridae]

You may have a situation to your fish that isnt typical. The GRF is not typically "oily" but I know its present.  You can smell it when you grind on the matrix, and the staff at the American quarry have talked about occasionally having some liquid petroleum seeps when exposing new quarry face.  

 

IF you are in the split layer, you dont want to scrape, you want to fracture.  Using a pin or x-acto blade, you push into the matrix, just behind the edge.  It causes a little section to break up and then can be gently blown away.  It does take some practice because if you are pushing too hard, you'll go through and leave the fish covered in tiny needle dimples.  I typically use a 2 - 3 percent paraloid or butvar solution, applied as I work, to keep the exposed fish from flaking and blowing away.

[Ptychodus04]

I don't have much to add here other than GRF material is tricky. It's soft, so it tends to be advertised as a beginner prep friendly rock. That's not really the case. 18" layer is pretty forgiving but Sandwich Bed (AKA Split Fish) material is a lot harder to prep.

 

I've never had oil seep from a fossil while prepping.