For Wim - Fossil prep. tools and method + new stacked images

[Bruce Williams]

Hi Folks,

Wim asked about the method used to prepare the the Ordovician sea bed fossil I posted at the end of August. If you haven't already seen it please check out this post.

The fossil was prepared by Jerry Rush who has kindly set out details of his methods and the tools he uses:

"Hi Bruce,

I'll try to give you a brief rundown on how I prepare my fossil specimens.

First, the equipment used.

The indispensable tool for the kind of preparation I do is a micro sandblast unit. This is operated by compressed air and basically blows an ultra fine stream of abrasive particles at the matrix that thefossil is found in. The goal is to remove the matrix while not abrading the fossil itself. To achieve this goal I employ a stereo microscope so that I have a very precise view of the fossil.

Some people use very soft abrasive with the idea that the fossil is harder than the matrix, but this only works when there is a substantial difference between the hardness of the two. I long ago abandoned this approach, and now rely on very careful observation and slow preparation to avoid damaging the fossil. It also allows one to prep fossils which are no harder than the matrix.

A micro abrasive blaster used by an unskilled preparator or someone who is in a hurry results in a very poor outcome. In my book, a fossil that isn't worth preparing carefully, isn't worth preparing. I use one micro-blaster for preliminary preparation (fast removal) and second one for the fine finish work. This saves very tedious changing of components for the two processes.

In addition to the micro-blasters, I use a variety of small air hammers and chisels, as well as rotary shaft grinders and air die grinders. These are fitted with either tungsten carbide bits or diamond bits. Tungsten carbide for the chisels and diamond for the rotary tools.

I have two large lapidary saws, one portable and one which is set up in my workshop. These use diamond blades.

My air tools and micro-blaster are powered by a large air compressor. In addition, since these processes all generate a lot of rock dust, I have a large industrial air filtering unit which removes the dust before exhausting outside.

Besides these motorized and air powered tools, I have zillions of dental picks, scratch awls, tweezers and miscellaneous hand tools. Of course I probably only use a handful regularly. Sort of like hats. I have a ton and only wear one or two. One never knows when a special need will come up though.

Fossil preparation is an activity which some people seem to have a talent for and some don't. I have known several collectors who went to the large expense of getting a sandblast unit, and after playing with it for a bit, never cranked it up again. Perhaps its comes down to a strong desire to accomplish something and an obsessive nature. I don't know. I do think that for a happy result you need to enjoy the process.

I hope I've managed to explain what I do to some extent. Let me know if you have any particular questions.

Best from Cincinnati, Ohio, USA, the land of the drought.

Jerry"

Here are a couple more stacks taken of the same fossil. The highest magnification pic covers an area of approx. 4x3 mm. The level of detail exposed by Jerry's preparation is quite incredible when you consider the small area involved.

Bruce

Nikon D80 ISO100, Stack of 11 frames using CombineZM


This image is just 4mm by 3mm in area.

[Mike B in OKlahoma]

Very interesting, thanks to you both for explaining that. I'd never have the patience for the process! Not to mention that I wouldn't let something that blows abrasives around in the same home where I keep and clean my camera sensors!

[Bruce Williams]

Thanks Mike .

Yes, I'm verging on paranoid when it comes to changing lenses so dust management would be an important factor. Jerry does touch on this:

quote: "...In addition, since these processes all generate a lot of rock dust, I have a large industrial air filtering unit which removes the dust before exhausting outside." .

Bruce

[rjlittlefield]

Good grief! These are excellent images and simply astounding fossil prep!!

Thanks for going to the trouble to put all this together -- much appreciated!

--Rik

[Bruce Williams]

Thanks Rik - Close-up and macro photography is a great way to explore these amazingly detailed fossils and certainly gives one an added appreciation of the work that went into their preparation.

Bruce

[Wim van Egmond]

Thank you Bruce!! It is magnificent. I bet it is dusty work! Indeed this should not be done near your camera set up. And I hope on his microscope the focus still operates well.

I hope to see more of this! The work sounds like fun to do when you live near fossil rich dry areas! The idea that you are staring at such an old fossil seafloor is thrilling, especially with details like this. I have a small fossil collection and with mostly small fossils. They are relatively cheap and often more detailed than the big fossils that sell for high prices!

Is Jerry a seller or does he do this as a hobby? It is a bit of a strange business, with a lot of fake stuff. That is why these small and subtle fossils are so interesting. This is real and this is about what makes fossils so interesting, being a window to the past.

Wim

[Bruce Williams]

Thanks Wim.

You know I feel exactly the same about this sort of dioramic fossil. It's like looking at a 3D photograph that (in this instance) was taken almost half a billion years ago. It's staggering to think that it was already unimaginably ancient long before the first dinosaurs roamed the Earth!

It's my impression that Jerry is principally an enthusiast although his work does come up for sale on eBay from time to time.

Bruce