First Serious Prep

[Bill Hoddson]

This is going to be my first serious attempt at removing a fossil from a rock, and cleaning it for display. 

 

It's a solitary horn coral found in a parking lot in Traverse City, Michigan.  Base rock is a rather coarse grained limestone, so it should be easier that a finer, densely grained matrix. 

 

The only tools I have currently are a Dremel with a flex attachment, carbide cutting disks and diamond burrs, as well as various dental tools and muriatic acid.  

 

My plan is to try to safely cut the specimen out of the main body of the rock, and then proceed with the finer details cleaning. 

 

Sorry if the photos aren't very clear.  All I have is an older smart. 

[Tidgy's Dad]

That looks pretty difficult to me.

I will be very interested to see the results. 

[tombk]

I agree that it looks like a tough first attempt. I’ve tried the Dremel cutting discs, and they don’t work so well in dense rock for a couple of reasons. The disc tends to get stuck and stops turning when you get into the rock, and the disc diameter is relatively small so doesn’t do well in matrix that is more than about half an inch or a bit more than a centimeter thick. 
the margins of the fossil don’t appear to be sharply demarcated from the surrounding matrix, which also makes it difficult. 
But you have to start somewhere, and a specimen that poses a personal challenge is a good place to get familiar with the benefits and limitations of your various tools. 
good luck and have fun and don’t forget the eye protection!

[Fossildude19]

I've had success cutting rock with a battery powered angle grinder with a diamond blade.

Corded one should work similarly well.

[FranzBernhard]

You are really starting with a tough one. And my opinion, you are going to ruin the specimen - its nice the way it is (I am a purist of some kind).

Is this the only specimen you have or the best specimen?
Franz Bernhard

[FossilDAWG]

I have to agree with Franz that the corals look good in the matrix, and they are likely to look less good if you were to completely free them from the rock.  Of course, that's just a matter of personal taste.  I would reduce the amount of matrix (you could perhaps trim it with a tile saw) and try to cut (or grind smooth) the back side and then polish it to make a nice cross section showing the internal structures.  The side of the specimen in the photo is pretty nice though IMHO.

 

Don

[Bill Hoddson]

34 minutes ago, FranzBernhard said:

You are really starting with a tough one. And my opinion, you are going to ruin the specimen - its nice the way it is (I am a purist of some kind).

Is this the only specimen you have or the best specimen?
Franz Bernhard

This specimen was actually found in a parking lot in Northern Michigan.  Not sure where the source material is, but it's just a short drive from several quarries in Devonian reef systems.  Basically,  specimens like this are a dime a dozen. I decided to attempt it due to the matrix - It's coarse grained, and doesn't seem to be heavily cemented. 

 

If it were a trilobite or a cephalopod  (neither of which I've ever found), I'd be more likely to leave it intact.  I figure this is a good specimen to try as it's common locally, and won't be a great loss if I screw up. 

[FranzBernhard]

1 minute ago, Bill Hoddson said:

I figure this is a good specimen to try as it's common locally, and won't be a great loss if I screw up. 

Please keep us informed. I am really very curious, how this works out! Thanks!
Franz Bernhard

[Bill Hoddson]

38 minutes ago, FossilDAWG said:

I have to agree with Franz that the corals look good in the matrix, and they are likely to look less good if you were to completely free them from the rock.  Of course, that's just a matter of personal taste.  I would reduce the amount of matrix (you could perhaps trim it with a tile saw) and try to cut (or grind smooth) the back side and then polish it to make a nice cross section showing the internal structures.  The side of the specimen in the photo is pretty nice though IMHO.

 

Don

Thanks for the advice,  but as I mentioned to @FranzBernhard, it's a dime a dozen parking lot find.  

 

For me, it's more of a personal challenge,  and something to keep me occupied while recovering from hip surgery.  And as specimens like this are locally common, it'll be no great loss if I screw up. 

[Bob Saunders]

I like it as it is. As said the cut side polished may look great. This is a piece of broken quarry limestone cobble I found sticking out of the ground while walking a right of way. I have been working on exposing the smaller one. I have made some of the dip on the upper side where damaged and make a label to put over it. Rasps, files, pocket knife what ever removes material. 

[Bill Hoddson]

@Bob Saunders - That is a nice looking specimen.  The color really contrasts well with the matrix, making it 'pop' as an eye catcher.  With mine, there isn't anything, other than texture, that makes it stand out.

 

Since finds like mine are so common locally, if it turns out nicely, I'll be giving it to my grandson, who has started his own collection. 

[FossilDAWG]

1 hour ago, Bill Hoddson said:

Thanks for the advice,  but as I mentioned to @FranzBernhard, it's a dime a dozen parking lot find.  

 

For me, it's more of a personal challenge,  and something to keep me occupied while recovering from hip surgery.  And as specimens like this are locally common, it'll be no great loss if I screw up. 

That's a different story then.  Good luck and have fun!

 

Don

[Bob Saunders]

2 hours ago, Bill Hoddson said:

@Bob Saunders - That is a nice looking specimen.  The color really contrasts well with the matrix, making it 'pop' as an eye catcher.  With mine, there isn't anything, other than texture, that makes it stand out.

 

Since finds like mine are so common locally, if it turns out nicely, I'll be giving it to my grandson, who has started his own collection. 

I have been looking at it and not decided if two horn corals or the smaller tail end sticking out due to the curvature? South West Michigan. 

[RJB]

Looks like a tuff prep job.  Looking forward to seeing the end result.  Good luck

 

RB