Help with working with 18" layer fish

[Chuck W]

Hello,  I'm about to start my first experiment in preparing an Eocene fish from the Green River 18 inch layer.  I've done some prep of fish from the "split fish" layer with some success.  But 

the matrix here appears much different!  I'll be doing with with a pin vice, scribe and a head band magnifier with good lighting.  I could use any advice from y'all with MUCH more experience 

than me!   Thanks

[Fossildude19]

Welcome to the Forum.  

 

Go slow, and keep your tools sharp.  

Good luck!  

[snolly50]

You are finding the matrix to be much harder than your split fish experience. You are also probably realizing that the piece smells like the underside of a '58 Buick. Obviously, your present challenge is more time consuming and just plain "harder" than the split fish. It can be accomplished with simple human-powered tools; but it will take time. The biggest issue to be aware of is wrecking your hands. The fine motor movement involved rapidly takes a toll on the muscles and supportive tissues of your mitts. It's easy to get involved in the task and let too much time slip by without a break. Be careful.

 

As a lower cost alternative to an expensive air driven stylus, I have utilized an ElectroStylus with some success. I'm not sure that tool is still available and I find the common Dremel engraver to be far to unwieldy for extended comfortable use. In addition the powered vibrating tools bring their own share of hand hazard.

 

As Tim wisely said; slow, sharp and I'll add, take a break. Good luck, have fun.

[Chuck W]

Thanks!  I read somewhere that wetting/moistening the matrix can help?  

[Ptychodus04]

5 minutes ago, Chuck W said:

Thanks!  I read somewhere that wetting/moistening the matrix can help?  

This can help on 18" specimens but you have to be very careful not to "over-wet" the specimen. The water will soften the bones as well as the matrix. The best advice has been said already, go slowly. If you hurry, you'll always make more mistakes. I have spent upwards of 50 hours on a single fish before, and that is using high end pneumatics and abrasives.

 

Enjoy the lovely smell of one of the most hydrocarbon rich oil shales in the US.

[FossilDAWG]

Has anyone tried using a weak acid, such as vinegar (5% acetic acid) to soften the matrix over the fish?  I realize one would have to be very careful not to undermine the bones.

 

Don

[Randyw]

I use an electric engraver for the bulk removal and then the hand tools with just a little water for the fine finish work. I will also repeat what the others have said. Go really slow and careful with multiple breaks. When I use water I’ll put just a bit on the area I’m working on and wipe off the excess before very long. Sometimes just a few drops at a time. I also keep the paraloid handy to protect the areas already done.

[Ptychodus04]

On 7/24/2020 at 10:09 AM, FossilDAWG said:

Has anyone tried using a weak acid, such as vinegar (5% acetic acid) to soften the matrix over the fish?  I realize one would have to be very careful not to undermine the bones.

 

Don

the Green River Formation is an oil shale (even though it is often referred to as a limestone and it looks like limestone). It is not reactive to acetic acid.

[jpc]

10 minutes ago, Ptychodus04 said:

the Green River Formation is an oil shale (even though it is often referred to as a limestone and it looks like limestone). It is not reactive to acetic acid.

Not all the GRF is oil shale.. only certain layers, such as the 18 inch layer.  The GRF in Utah and CO (deposited in Lake Uinta) is much more consistently oily than the WY GRF.  

[Ptychodus04]

3 hours ago, jpc said:

Not all the GRF is oil shale.. only certain layers, such as the 18 inch layer.  The GRF in Utah and CO (deposited in Lake Uinta) is much more consistently oily than the WY GRF.  

Thanks for the info. I thought all of it was considered oil shale but it makes sense that some isn't. The split fish/sandwich beds aren't very oily at all.

[RJB]

On 7/24/2020 at 9:01 AM, Ptychodus04 said:

Enjoy the lovely smell of one of the most hydrocarbon rich oil shales in the US

I think im one of the guys who likes that smell. 

 

RB

[Ptychodus04]

3 hours ago, RJB said:

I think im one of the guys who likes that smell. 

 

RB

Me too. Smells like history.