Jump to content
Sign in to follow this  
HighSide

Stabilisation for fish fossil

Recommended Posts

HighSide

Hello everyone,

 

I went out this weekend in the Oligocene of southern France to look for fishes. I have found some, but I have many questions since they are my first fish fossils and I am having several problems for preparation, and stabilisation.

First here are some examples of fossils found:

 

869376FullSizeRender2.jpg

 

 

611248FullSizeRender1.jpg

 

236542FullSizeRender4.jpg

 

Some of the layer are extremely thin (as paper) and the fossil start to ondulate as long as it gets dry and I was wondering how could I overcome this problem?

 

420596FullSizeRender3.jpg

 

Some of them are more thicker, but still ondulating.

 

905593FullSizeRender.jpg

 

My second question is how do I prepare them in order to keep the bones? I have tried to prepare small chunks, but as long as I separate the two layers its very hard to keep all the bones intact. I have tried with some HCl, but it doesn't gets through the most blacky parts, which are the richest in OM. Maybe a small schisel ? Before starting to do anything I wanted to have some advices from you guys. Thanks for your help !

 

Share this post


Link to post
Share on other sites
Raggedy Man

Wish I could help, but those look amazing.

Share this post


Link to post
Share on other sites
Kane

Although this is about plants, this thread might be helpful:

I know @Ptychodus04 has prepped fish before, so hopefully when he has time he could offer his expertise on how to stabilize and prep these fish. :)

 

Share this post


Link to post
Share on other sites
Harry Pristis
47 minutes ago, FossilDAWG said:

Sometimes a key to preventing warping ("ondulating" or more correctly "undulating") is to slow down the rate of drying.  Wrapping the fossils in aluminum foil, or newspaper and then covered in plastic wrap, can slow the drying rate.  Warping/cracking happens when the rock dries unevenly, which is common when it dries too quickly.

 

For stabilization, butvar or paraloid B72 in acetone (dries rapidly) or ethanol (dries more slowly) is better than diluted white glue.  There are several threads discussing consolidants if you do a search in the Forum.  Forum member @Harry Pristis has some excellent recommendations somewhere on his web site as well I recall.

 

A thin exacto knife or single-sided razor blade may ne better than a chisel for splitting that shale.  The thinner the blade, the less likely you will bend the shale and make it crumble.

 

Don

 

Good advice from Don!  There are extensive discussions in various threads here.  My own experiences are posted under my TFF profile, the "About Me" button.

Share this post


Link to post
Share on other sites
RJB

Hey HighSide.  For that thin undulating rock, i would put in on some newspaper, cover with siran wrap and place a big book on top for about a week or two.  You want to slow down the drying like FossilDawg says.  Then i would glue the intire thing onto some fiberbaord, then its time for prep.  Good luck.   This, to me, looks like a very challenging but fun project. 

 

RB

Share this post


Link to post
Share on other sites
HighSide

Hello everyone,

 

Thank you for all this answers, I am sorry about the grammatical mistakes my level in written english has decreased... (I am not a native speaker, but I should practise more!) 

I will follow your advices as soon as tonight and will have a look this weekend to see how it works hopping that cracks wont appear as it dries.

 

I wasn't aware of this consolidant techniques thanks. So you mean that as long as I prepare the fossil I apply one of this solution (paraloid B72 in acetone (dries rapidly) or ethanol (dries more slowly)) to keep up the work in order not to dammage the bones ? (I am asking because I am not sure to have understood exactly the meaning of the sentence Don. :) 

 

So:

 

Step ONE: Wrapping the fossils in aluminum foil, or newspaper and then covered in plastic wrap, with books at the top to keep it horizontal.

 

Step TWO: glue the intire thing onto some fiberbaord

 

Step THREE: Start preparing with thin exacto knife or single-sided razor blade and as long as I prepare the fossil I apply one of the consolident solution proposed above.

 

Is this exact?

 

Thanks,

 

Arno

 

Share this post


Link to post
Share on other sites
Ptychodus04

Arno,

 

Don't worry about the grammar. Some of us native English speakers aren't very good at it either!

 

You have the steps right. The truck on the drying is for it to go slow. It should take a week or so to dry. This will help minimize cracking and warping. Some cracks may still appear but you can pour the paraloid solution into them to hold them together.

 

I apply small amounts of the solution as I uncover bones to keep them from breaking off. Go slow and use some kind of magnification for the best results.

Share this post


Link to post
Share on other sites
RJB

Dont put newspaper onto the top of wet rock.  It could get stuck on there purty good and also leave some ink in the rock.

 

RB

Share this post


Link to post
Share on other sites
HighSide

Thanks guys. To bad I wont read my news paper on my fossils ahah. I will let you know how it goes thanks ! :)

Share this post


Link to post
Share on other sites
Ptychodus04
5 hours ago, RJB said:

Dont put newspaper onto the top of wet rock.  It could get stuck on there purty good and also leave some ink in the rock.

 

RB

 

I like to use an old bath towel. Throw a bit of water on it. Wrap the wet specimen and put it in a cardboard box for a few weeks.

Share this post


Link to post
Share on other sites
FossilDAWG

The reason I mentioned fast (acetone) vs slow (ethanol) evaporation is that sometimes the fast drying may work against having the consolidant penetrate deeply into the rock.  In that case you can soak the rock in the acetone consolidant solution, but be careful and try this first with a spare piece of shale without any fossil you care about.  Sometimes immersing the rock in a liquid will cause it to fall apart!  Alternatively ethanol dries more slowly so it can wick further into cracks in the rock before it dries.  However, paraloid and B72 are less soluble in ethanol.  

 

If the consolidant leaves an unattractive shiny surface after it dries, a quick dip in acetone can remove the surface layer without stripping the consolidant deeper in the rock.

 

Whatever you do, try it first on scrap pieces of shale to refine your technique before risking your fish fossils.

 

Don

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×