Beginner Ammo Prep

[Axelorox]

Hello all,

I currently have these ammonites from a trade with another forum member. They were collected from Carlile shale in New Mexico.

I am hoping to prepare them, but have no experience with this kind of thing. What tools (preferably not too pricey) and methods would be best to use on these?

I'd do my practicing on one of the smaller ones first, and hopefully will be able to end up with a nice result on the larger ones.

Edited October 13, 2014 by Axelorox

[Raggedy Man]

I began using an old dentist drill and dremmel. Most people use pneumatic tools, but they can be pricey. Also with pneumatic tools you need a compressor, which also bumps the price up. I watched a video a few weeks back posted here by a member that showed a kid prepping a fossi with nothing more than a wood broom handle used as a hammer and an old rusty nail.

Needless to say that blew my mind. The set up I did for my wife is simple. A dremmel suspended by a bungy with many many many replacement tips...lol.

I highly stress the use of a mask or some other ventilation as you do not want to inhale that dust.

Best of luck to you in your quest to learn fossil preparation.

Best regards,

Paul

[tmaier]

I use a vibro-pick, rotary dremmel with many attachments, exacto knife, paint and tooth brush with water and vinegar, jewelers screwdrivers, and dental pick. I have a whole box of little tools for picking, poking, nipping, grinding, etc.

The trick to do it, if you can, is to come in from the side and remove matrix towards the fossil, and then when you get to the matrix-fossil boundary, you hope it pops off cleanly. If the matrix sticks to the fossil tenaciously, then you have a problem. If you are working on the surface of the fossil itself you can accidently leave tool marks.

Start learning your matrix and tool behavior on the back of the fossil.

Take breaks so you don't get a case of "shaky hand". Otherwise you slip and gouge the fossil.

It's slow work, so pop in a movie.

I heard that Dremmel makes a vibro-engraver. I haven't seen it and my local Walmart doesn't carry it, but I trust that brand name.

A vibo tool acts like a miniature jackhammer. Don't expect miracles, but rotary tools are too dangerous to use when close to the matrix-fossil boundary.

Expect some negative comments from those elitist guys with the sandblaster tools.

[snolly50]

The best course of action depends on the nature of the matrix and its relationship with the fossil. Does the matrix separate with ease from the material or does it cling? If there is a natural tendency to separate (the popping off mentioned above) at the appropriate juncture; then an engraving tool instead of a grinding rotary device will prove superior. tmailer mentions a Dremmel vibro tool. I have one and it is nicely powerful. However, I find its shape awkward and its heavy and noisy. It fatigues my hand rapidly. I prefer the pencil-shaped ElectroStylus. The ElectroStylus costs more. The Dremmel I found at my local Lowes store.

Again, how you should best proceed is determined by the nature of the piece itself. I can give you a bit of universal advice that will certainly apply to any technique - protect your eyes.

[rejd]

I agree with what everyone else has been saying. slow and steady, especially near the fossil. I used a dremel engraver http://www.dremel.com/en-ca/Tools/Pages/ToolDetail.aspx?pid=290-01 for a while and it worked quite well. It is pretty loud though and can be hard to grip for long periods of time. I now use an air scribe which is much nicer and can provide a bit more finess. Best of luck and I look forward to seeing your results.

[Axelorox]

Thanks for all the advice everyone!

So far I am leaning towards the Electro-Stylus. The comments about the uncomfortableness have made me hesitant about using the Dremel engraver, and I don't want to get into the compressors needed for pneumatic tools.

Would something like the Electro-Stylus be able to used for other types of fossil prep like fish specimens?

@tmaier - What purpose does the toothbrush with water and vinegar serve?

Edited October 12, 2014 by Axelorox

[snolly50]

Thanks for all the advice everyone!

So far I am leaning towards the Electro-Stylus. The comments about the uncomfortableness have made me hesitant about using the Dremel engraver, and I don't want to get into the compressors needed for pneumatic tools.

Would something like the Electro-Stylus be able to used for other types of fossil prep like fish specimens?

@tmaier - What purpose does the toothbrush with water and vinegar serve?

I have used the ElectroStylus on Green River fish. It handles that matrix very well. I do not doubt that air powered rigs can turn out a perhaps superior result and faster*, but the expense is an issue as well as the need for a dedicated space with all the attendant peripherals. The ElectroStylus at about $75 is twice as expensive as the Dremmel device. If you wish, look at "Oreodont Prep Series" under this topic. There you will see a little work done with the ElectroStylus.

*and in the case of air abrasive, with more precision and finesse.

In the case of your ammonites, If they were mine, I would poke around a little with a dental tool in an effort to judge the hardness of the matrix and its affinity for the fossil. (Can you get pieces to pop away cleanly from the fossil?) You should be able to tell if the fossil will separate readily. Such an exercise may help you to avoid committing to a tool that may not be suitable to your current need.

Edited October 12, 2014 by snolly50

[Axelorox]

In the case of your ammonites, If they were mine, I would poke around a little with a dental tool in an effort to judge the hardness of the matrix and its affinity for the fossil. (Can you get pieces to pop away cleanly from the fossil?) You should be able to tell if the fossil will separate readily. Such an exercise may help you to avoid committing to a tool that may not be suitable to your current need.

The matrix seems kind of crumbly - I was able to pop some off just using my fingers. I guess I would not need an overly powerful tool then?

[snolly50]

The matrix seems kind of crumbly - I was able to pop some off just using my fingers. I guess I would not need an overly powerful tool then?

If the matrix is coming cleanly away with finger pressure, an engraving tool would take care of it in a short while. I'm assuming the fossils themselves are hard and not crumbly, like the matrix; that would complicate matters. I often use a pin vise with a carbide needle (the needle costs more than the vise). If the matrix you have is universally workable, as you described and the ammonites are hard and stable; you could probably progress quickly and inexpensively using simple tools - needles, picks. Most of all have fun; prepping to me is the most enjoyable portion of this whole avocation.

[Axelorox]

Yeah for the most part the ammonites are hard. However the last one has a few cracks and does seem to be a bit more fragile than the rest.

With the pin vise and needle would it simply involve scraping away at the matrix by hand?

Edited October 13, 2014 by Axelorox

[snolly50]

Yeah for the most part the ammonites are hard. However the last one has a few cracks and does seem to be a bit more fragile than the rest.

With the pin vise and needle would it simply involve scraping away at the matrix by hand?

Yes, if you are close to the fossil, gentle scraping to pulverize the obscuring matrix is the way to go - without scratching or gouging the fossil. However, it is also very useful to exploit any cracks or depressions in the matrix to try and pop off chunks. This eliminates material quicker than eroding it away. You can also be creative with the tool employed for this mechanical approach. A small screwdriver, like for glasses repair could be useful, If you don't mind ruining it. Depending on the characteristics of the matrix, an Xacto knife makes a fine matrix reducer. Again, especially when using tools in a manner in which they were not intended; protect your eyes. Oh, protect everything else too. LOL I once leaned over to pick up something off the ground and jammed a large engraving needle a half inch into my pectoral muscle. OUCH.

[Axelorox]

Thanks for all the advice.

[John K]

http://www.thefossilforum.com/index.php?/topic/49000-first-prep-hoploscaphites/

I prepped my first ammonite from the Bear Paw with a Dremel engraver and rotary grinder.

and yes, most definitely, wear eye protection!

Edited October 13, 2014 by John K

[Axelorox]

Thanks for the link! Seems like most of the ammonite preppers on here use some sort of polish on the final product.

[Triceratops]

Be sure to post pictures as you go along!

[Axelorox]

Well I started working on these today with the Electro-stylus. Some questions/issues:

What kind of surface should the fossils be on when I'm using the engraver? Currently I hold them in one hand, but would this cause cracks from the stress of the engraver?

What type of glue can I use to bond cracked pieces together or seal pre-existent cracks in the fossil?

The electro-stylus is great for detail work and chipping off thin matrix left on the fossil surface, but it is not really suited for removing large bits of matrix at once. Would a dremel tool be better for this?

Overall everything is going well (albeit slowly), with the only issue being one piece that cracked off. It's a very clean break and should be easy to glue back. Now I have a lot more respect of what it takes to prep all the ammonites I see offered for sale!

[Auspex]

As to glue; so long as you don't need slow set time (for aligning pieces), cyanoacrylate is a good choice.

[Axelorox]

As to glue; so long as you don't need slow set time (for aligning pieces), cyanoacrylate is a good choice.

Thanks for the suggestion; cyanoacrylate is something I already have on hand and I can snap the broken piece back into position pretty quickly so that should work. Any idea on what to use to strengthen cracks?

[Auspex]

... Any idea on what to use to strengthen cracks?

Just wick some in and let it set; excess can be removed later by gently wiping with acetone.

[snolly50]

Well I started working on these today with the Electro-stylus. Some questions/issues:

What kind of surface should the fossils be on when I'm using the engraver? Currently I hold them in one hand, but would this cause cracks from the stress of the engraver?

No, I believe your hands are probably strong enough to resist cracking.

Sorry, I could not resist.

I use a folded bath towel for the fossil to rest upon when using an ElectroStylus. For larger chunks of matrix it is possible to cut a "slot" using the ElectroStylus. Making a series of these cuts in proximity allows you to come back with the tool held a 90 degree angle and break loose larger chunks of matrix. This is often quicker than pulverizing it completely. It just takes some practice and experience with the material you are working to get a feel for the process.

[Axelorox]

I'll give that strategy a shot. I've been using the carbide tip so far - is that what you use?

[Triceratops]

No, I believe your hands are probably strong enough to resist cracking.

Sorry, I could not resist.

I use a folded bath towel for the fossil to rest upon when using an ElectroStylus. For larger chunks of matrix it is possible to cut a "slot" using the ElectroStylus. Making a series of these cuts in proximity allows you to come back with the tool held a 90 degree angle and break loose larger chunks of matrix. This is often quicker than pulverizing it completely. It just takes some practice and experience with the material you are working to get a feel for the process.

Te he!

[tmaier]

Axelorox,

You asked me what the water, vinegar, and brushes were for...

When you get down to the fossil, then sometimes you have very fine particles of limestone that are still sticking to the fossil. You can wet the fossil with water, then apply some vinegar, wait a minute, then give it a scrub with the toothbrush to knock the particles off. If you try to knock them off with the vibro pick, you are likely to leave tool marks. You can also try pushing them off with a dental pick or jewelers screwdriver. Anyway, the vinegar is for fine clean up work. Look at the photo below, and the dark fossil was cleaned up in the final stages by repeated brushing with vinegar.

Snolly's advice about removing lots of matrix by digging rows with the vibro, and then use a screw driver to pop off chunks is very handy. I will also use a rotary dremmel with a cut-off stone disk. You can get a pack of them cheap. You will need a pack of them because they crack and fly apart pretty often. They also wear down fast. You van cut fine rows in the matrix, insert screw driver, and then twist it, and whole chunks will come off. In the photo below, the large gastropod was 50% embedded in matrix, but using the dremmel I popped off large chunks, and then did the finer work with the vibro to pop matrix off near the fossil surface. Then a brush up with water and vinegar. I left that small chunk of matrix, and flattened the bottom off by cutting with the disks, to make a matrix pedestal. Now it is 90% exposed and sits nicely like a paper weight on its matrix.

These cut-off disks fly apart at high speed, so wear some form of eye protection!

There are a lot of cheap attachments for the rotary dremmel you can get.

Another trick I use, I call "pedestaling". You cut deep slots in the matrix in with the dremmel or the vibro, to under cut large chunks of matrix. You make the unwanted matrix sit on a pedestal, then you sneak your screwdriver into the cuts and twist... the whole chunk comes off. You can remove a lot of matrix quickly this way. As Snolly mentions, trying to removing large chunks of matrix by vibroing through the whole thing would take forever, so you need to learn to pop chunks off for the large work.

The bad part is if there are other fossils in the matrix, and you find you have cut into them. Another problem is if you are not familiar with the anatomy of the fossil you are working on, and damage it by being overly aggressive in the wrong places. Study the anatomy of other fossils of the same type before trying to prep one.

And I sometimes use the vibro tool by holding the fossil in my hand, or have the fossil on a towel, or sometimes have the fossil on a hard surface. If you have it on a hard surface the vibro will be more aggressive, but sometimes you want that gentle touch, so using a method of holding the fossil that allows some vibration recoil absorption like a towel will give you extra finesse, for those delicate areas.

Good luck and show us your progress.