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Heteromorph

Right now I am almost exclusively hunting in the Austin Chalk Formation. I am curious what tools I would need to crack open chunks of it to look for fossils. What kind of chisel and hammer would be recommended? Is that all that would be needed? The matrix that I am working with is medium hardness.

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Foozil

What are the fossils you're finding inside the chalk like? Hard or crumbly?

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Heteromorph
1 hour ago, Foozil said:

What are the fossils you're finding inside the chalk like? Hard or crumbly?

Other than oyster shells or echinoids, one of my most common finds are steinkerns which are basically as hard as the matrix that surrounds it. The shells that I find are hard. 

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Foozil
12 minutes ago, Heteromorph said:

Other than oyster shells or echinoids, one of my most common finds are steinkerns which are basically as hard as the matrix that surrounds it. The shells that I find are hard. 

Ok sure. One thing that I would be taking into consideration is wether you'd be harming the fossils. Does the rock split in sheets or does it just break off in pieces? 

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Heteromorph
10 minutes ago, Foozil said:

Ok sure. One thing that I would be taking into consideration is wether you'd be harming the fossils. Does the rock split in sheets or does it just break off in pieces? 

Chunks.

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Foozil
4 minutes ago, Heteromorph said:

Chunks.

Well in that case, does it matter if you whack it with a hammer or try and chisel it? Sounds like just hitting it with a hammer sounds like your best bet.

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Herb

I dug out an ammonite (6" diameter) out of the chalk. I used a Dremel Vibratory tool for most of the coarse work and a fine engraver for the rest . About $25.

x290lg.jpg.pagespeed.ic.hSGZGxgxw_.jpg

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Tidgy's Dad

If this chalk works the same way as English chalk, i'd just wack it with the hammer. 

Repeatedly. 

 

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Heteromorph
35 minutes ago, Tidgy's Dad said:

If this chalk works the same way as English chalk, i'd just wack it with the hammer. 

Repeatedly. 

 

This might be a silly question, but what kind of hammer would you use? How big? I am all questions. :P

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Tidgy's Dad
3 minutes ago, Heteromorph said:

This might be a silly question, but what kind of hammer would you use? How big? I am all questions. :P

Here is Harry.

WIN_20180130_040549.JPG.72ead36ccd1a2d53c87282b9fcc120fc.JPG

A good weight. 

But i've been known to use sledge hammers when needed..................

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KimTexan

I think I’d use a little 3 lb sledge hammer. If you want to be more precise I’d use a chisel with hand guard with the sledge hammer. The width of the chisel may vary depending upon how accurate you want to get.

Here are examples of what I’m talking about from Amazon.

FF619C23-E3DC-449E-AC23-E7250118AA90.thumb.jpeg.82a1e36b68912c54835139dda03c89cd.jpegC65D9F53-3D91-4FE4-95D9-3F4FD0B85026.jpeg.c7221edcd0997e411b316071fc9c535a.jpeg

 

If i know the rock is likely to split through the fossil sometimes I’ll drill holes around the edge of the fossil to improve my odds of not breaking the fossil. Sometimes the fossil splits anyway.

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JohnBrewer
17 hours ago, Tidgy's Dad said:

Here is Harry.

WIN_20180130_040549.JPG.72ead36ccd1a2d53c87282b9fcc120fc.JPG

A good weight. 

But i've been known to use sledge hammers when needed..................

Superb photo Adam, your expression and hammer. Hope I don’t meet you on a dark night!

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Ludwigia

Like everyone is suggesting, slugging that stone with any kind of heavy hammer should do the job. You can even use a proper sledgehammer on big boulders. If there's a good separating layer between the fossils and the matrix, then ideally they should pop out. In stones where you can't determine where the fossils are, it's almost guaranteed that some of them will break into pieces, but that is unfortunately part of the game, so you might as well get used to it. If you can determine where the fossils are before you go to work on the stone, then slug it on the other side first. You can also place chisels accordingly depending on how the fossils are lying in the stone. What kind of form they have can determine whether you use a flat or pointed chisel.

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Tidgy's Dad
1 hour ago, JohnBrewer said:

Superb photo Adam, your expression and hammer. Hope I don’t meet you on a dark night!

I thank you. 

I do my best work at night. 

But hopefully we'll meet up in the day one day, John. 

Though I can't guarantee not to be slightly scary. :D

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Sagebrush Steve
On 1/29/2018 at 6:41 PM, Herb said:

I dug out an ammonite (6" diameter) out of the chalk. I used a Dremel Vibratory tool for most of the coarse work and a fine engraver for the rest . About $25.

x290lg.jpg.pagespeed.ic.hSGZGxgxw_.jpg

Did you use the carbide tip that came with it or did you use some sort of diamond tip?  My wife just asked me if I had an engraver she could use to mark her name on some scissors she loans out to the local quilt guild.  I said no but if she really wanted me to, I could go buy one at the local Home Depot.  She was happy I was willing to do so for something she will only need once. B)

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Herb
7 hours ago, Sagebrush Steve said:

Did you use the carbide tip that came with it or did you use some sort of diamond tip?  My wife just asked me if I had an engraver she could use to mark her name on some scissors she loans out to the local quilt guild.  I said no but if she really wanted me to, I could go buy some at the local Home Depot.  She was happy I was willing to do so for something she will only need once. B)

I used the one that came with it

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Ptychodus04

I like a 1" chisel rather than a wider chisel. Less swinging to make the rock break. I also use a 3# hammer.

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Heteromorph
3 hours ago, Ptychodus04 said:

I like a 1" chisel rather than a wider chisel. Less swinging to make the rock break. I also use a 3# hammer.

How many LBs is your hammer?

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Ptychodus04
37 minutes ago, Heteromorph said:

How many LBs is your hammer?

 

3 pound (3#)

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Heteromorph
5 minutes ago, Ptychodus04 said:

 

3 pound (3#)

Thanks! I wasn't familiar with the terminology. :headscratch:

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Ptychodus04
1 hour ago, Heteromorph said:

Thanks! I wasn't familiar with the terminology. :headscratch:

 

No worries. The # is the sign typically used for pounds (other than British Pounds Sterling).

 

Of course, all generations after Gen X know it as a hash tag. I’m getting old.:faint:

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Heteromorph
17 minutes ago, Ptychodus04 said:

 

No worries. The # is the sign typically used for pounds (other than British Pounds Sterling).

 

Of course, all generations after Gen X know it as a hash tag. I’m getting old.:faint:

I guess my inexperience shines through somtimes. :ighappy:

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Ptychodus04
2 hours ago, Heteromorph said:

I guess my inexperience shines through somtimes. :ighappy:

 

Mine does regularly. :D

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Heteromorph
9 minutes ago, Ptychodus04 said:

 

Mine does regularly. :D

Your inexperience would be much more experienced than mine is. :P

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