Fossil Prep Workshop

[Terry Dactyll]

Theres a few people showed some interest in the fossil preparation that I do, and I know from the outside it looks like magic as you end up with something stunning to look at, where the reality of it is quite different... Its basically a series of techniques and tools, that after gaining experience using them you can apply to any given situation...rarther like any skill base in any field.... I have to add ...I do think having an artistic eye is beneficial.. although not essential ...along with an undertanding of the shapes you are dealing with, to enable you to plan ahead as your uncovering your fossil.... Having patience is obviously of prime importance... its not something that can be rushed without having a knock on effect on the quality of the finished fossil....What I will try and do is put into words and pictures something I just do.... Ive never seen any text books on Prep, so if anyone has any valid comments to add, feel free to contribute...

Assessing the fossils potential... the first thing I do is to try and get a feel for the orientation of the fossil, the boundries it occupies within the rock, how best it could be displayed, ie which way up it would look best, is there enough rock to cut a base on it to make it free standing etc... so its worth sitting and having a think about what your doing, looking at the rock before you start.... Its called planning ahead, and we do it all the time without realising it... the same applies to fossil prep.... dont just grab your airpen and go.... you will soon be dissapointed...

Bulk Rock Removal... I use two methods for bulf rock removal....

Hammer and Chisel... this method is very effective and has been used in one form or another for thousands of years.... Rock has a grain structure, and this structure can be strong in one direction, but quite easy to split in another direction... work this out and use it to your advantage...sometimes rocks that contain lots of calcite have set or semented quite heard, and in these cases, it can have a mind of its own when hammering ... so just get a feel for what you have infront of you... start on somthing that isnt important.... even exposing a fossil in the field, you can begin to learn how the rock behaves, and apply this knowledge at a later date to your prep...wear suitable safety equipment, goggles & gloves to avoid injury...

Cube'ing....This involves taking a thickness of rock off upto any depth you can achieve with a stil saw blade off a slab of rock containing a fossil... Using stil saws is quite dangerous, so its important you fully understand all the safety requirements before you start, and its also noisey and dusty... so wear eye and ear protection and follow all the safety precautions.... a series of cuts are used to roughly the same depth across the surface of rock to be removed in the shape of a chessboard, creating one inch square .. 'pillars'.. of rock that simply knock off quite easily with a hammer and chisel.... you can cut down into the rock to a depth of say 6 " so it is quite effective at bulk rock removal... Keep monitoring what you are doing during cutting, incase you uncover anything else, and dont try and get too close to the fossil in one go.... confidence comes with experience.... this is also a good tool for cutting bases on fossils so they stand up in their own matrix...

[Terry Dactyll]

Compressed Air Tools....Most compressed air tools have quite a high air consumption so its essential you aquire a compressor with a decent capacity storage tank.... Im running a 70 litre compressor at the moment and when im using the die grinders or chisels, it is running continuously to maintain the pressure I need.... With a bigger storage tank, say 150 litres, this would not really be much of a problem....It would have long quiet spells before needing to fire up and refil the tank....also compressors can be noisey, so its important you consider this when thinking of buying one.... there are quiet compressors on the market which cost probably two or three times the amount of conventional compressors....

Air Chisels... These are good for removing upto 3-6 mm of rock at a time... after the inital bulk material has been removed, while you are getting closer to the fossil... a smaller chisel point is more effective for removing greater a thickness as the force from the chisel will then be applied to a smaller cross sectional area... you can see in the photo ive flattened an area of rock adjacent to the stil saw finish, quite quickly in less than a minute using this equipment... eye protection is essential....

Die Grinder.... These fitted with tungsten burrs and grinding tips can quickly smooth off a section of rock, or remove a concave area getting closer to the fossil... they utilise quite a high air consumption, but again are quite effective... In less than a miniute I smoothed over the surface of the flat area I had just created with the air chisel... Eye protection is essential....

Airpens.... I use a Chicargo CP pen for the bulk of my work.... without going into too much detail at this point regarding techniques, and treating it as a mechanism for matrix removal, its very easy to think a cp pen will remove 2-3 mm of rock across a surface .... you use it like you are ploughing a field, applying an even pressure, creating furrows in the rock... the next pass you do at 90 degress to the first, taking the tops off the previous furrows... it can be very effective....The forward exhaust of the air greatly assists visibilty when using this type of pen, blowing the dust and grit away as you progress... Eye protection is advisable... following manufacturers guidelines... and use a good quality dust mask....

Arrow Airpen... The second airpen I use has an extended tip fitted and is not quite as heavy duty as the CP... it is great for intricate work, doing centres of ammonites or in between ribs, where the CP pen is proving to be too strong... I use this to great effect under magnification on small nodular material... it is very controllable... and adequate for soft matrix.... Follow manufacturers reccomendations regarding safety....as well as a good quality dust mask

Mini Die Grinder... These are good as finishing tools for smoothing off the matrix when fitted with various small grinding stones... they usually have a 3mm collet so most dremel type attachments will fit into this tool.... unfortunately they have a rear exhaust which doesnt allow the dust to be blown away.... i tend to hold the tool one handed, and bend the exhaust tube round to blow back onto the work.... this has some success, but you find yourself stopping and restarting after having to blow the dust off.... a good quality dust mask is an essential bit of safety kit when using these, even if carried out ...outdoors....

[MikeD]

Thanks for the tips.

[Terry Dactyll]

Mike ... No problem.... I just hope it gives an insight into the tools available for people thinking of prepping their own fossils.... As with everything its practice, so dont start on your best fossil.... have a go at some broken pieces first....

Theres a couple of pen techniques I use besides using it as a point to cut into the rock.... The first is planing or skimming the rock off...which you can do when you start getting close to the fossil, maybe a couple of millimetres away.... It involves angling the airpen so the point is just litterally touching the surface skimming a very fine layer of rock away almost as dust.... you can very easily control this when you get proficient and it saves scarring the fossil as your not pressing in at an acute angle... couple this with a colouring in motion moving the pen across a cem or so and progressing forward... it becomes quite effective at removing the rock...If you have a decent air abrasives kit this is what you would use here, but I dont have that yet, so i have had to adapt what tools I do have .... to do the job...

Planing/Skimming the rock

The second technique I use is for digging down to get deep centres out say on a nautilus... I move the airpen in a circular motion covering a half centimetre diameter area, and am digging down at the same time... The front exhaust of the airpen usualy clears the debris, but you need goggles as it usually blows back straight in you face... Both these techniques need practice as the last thing you want is to scar the fossil....Ive got some images of a double ammonite I did a while back to show you the progress or steps involved... If I remember right it took 90 hours to complete it.... The lower images show the polishing of the calcite and the amount of centre that was missing due to crushing during fossilisation and reconstructed, carved within the rock.....

Anyone fancy doing anything on Air Abrasives.... im all ears....and I hope this what those were interested was looking for....

Edited September 24, 2009 by Terry Dactyll

[Nicholas]

I pinned this topic because it is very useful to new aspiring preppers. You've done an excellent job Terry.

[fossisle]

Terry

What coatings do you use to finish your ammonites?

[tracer]

yeah, this is very, very interesting. and it emphasizes what should have been but isn't always obvious - that the key is extreme patience and huge effort. but the right tools can help reduce that.

air abrasives - air abrasives are magical. it is astounding to see fine detail on fossils emerge effortlessly from ugly, unrecognizableness. and when the fossil's right, and the abrasive's right, and the air pressure's right, you're rapidly turning snarge into diamonds and it's wonderful. especially when you've got on magnifying lenses and can witness the transition occur in all its glory.

[Dicranurus]

Thanks Terry for the useful guide.

[fosceal2]

Wow I really enjoyed this article! As a small jewelry store owner I would like to share the regret I have that we did not buy a silent compressor! My husband,the jeweler,has equipment that runs on an air compressor and it is REALLY NOISY!

Fosceal

[Terry Dactyll]

Thanks Chaps....and glad it meets with your approval....anyone fancy doing any additions to it with say photos and an abrasives media guide... and types of equipment youve tried etc.... I think it would be a great contribution to the thread.... Theres someone I could ask to help me put something together, but I'll wait and see what appears... I know theres some knowledgeable guys amongst you.... and looking at your fossils, I know more than one of you will be using the abrasives kit....also, people who manually prep, using pin vices, dental tools etc....im sure you have loads of tips that people would find useful....Just tag em on the end of this...

Fossisle....I use marble floor polish mainly... and Artists varnish on the 'odd' one... both can quickly and easily be removed with white spirits on a rag, if you feel like a reprep...

[fig rocks]

Thank you Terry for the wonderful knowledge that you have shared!

[Eureka]

Terry,

Thanks a lot for your detailed explanation. it is an unbelievable bible for a begginner preparator.

You should film your fossil preparations and...who knows, distributing them between all fossil lovers.

Cheers,

Eureka

[Bear]

Very nicely done, sir. Thank you for sharing with us.

[siteseer]

... Using stil saws is quite dangerous, so its important you fully understand all the safety requirements before you start, and its also noisey and dusty... so wear eye and ear protection and follow all the safety precautions....

Yes, no matter what you're doing while prepping, always wear eye protection. It's not just the dust, flying rock particles, and solvents. One time, I was cleaning off some glue with a scalpel, pressing harder than I thought, and the tip of the blade snapped, bouncing off the left eyepiece of my safety glasses before I realized what happened.

It's easy to downplay the dangers and push your luck but your number will come up someday. Just put your glasses on each time you prep and be ready.

[Nicholas]

Good advice, I once slipped with my rotary tool which had a metal cutting disk in it. I had a very nasty wound on my hand on it for some weeks afterward.

[barefootgirl]

Thanks!

[djasper]

Very helpful...Thank you

[grampa dino]

I love your work and the fossils

That was a very good read.

Did you Know that here in Alberta

One needs a permit to do any type of work

on any fossil even just washing could be a big NO NO

What are if any the regulations in your world

[davehunt]

Thanks Terry for this detailed post.

Dave

[Terry Dactyll]

Cheers for the kind comments....

grampa dino..... ''What are if any the regulations in your world''?....you own what you find basically, and as a consequence can decide whats happening to the fossil...

[bigjohn835]

How did you know that other fossil was below? I am always amazed by the ability of people on here to look at a rock, (that I would pass over), and know that there's a fossil under there. Most fossils I prep, never seem to be in one piece. Most comes off really easy, then it just stops.

[Terry Dactyll]

bigjohn835....I wish I could say it was my xray vision or gut feeling or even a 6th sense, but in reality it was a keel showing like in the photo below.... Dont tell anybody, but once i got it home and started cleaning it, i found the edge of a third i had left in the rock.. .. it should of been a triple .... so I need some more lessons myself....

[Terry Dactyll]

Arthropleura armata prep Job

I suppose you could call this method selectively weakening a rock, to 'hopefully' do what you want when you ...'smack it ' with a hammer & chisel... lol

Something a bit different that I did a while ago after finding a rarther large carboniferous nodule that split totally wrong leaving a significant part of the positive (part) still attached to the negative (counterpart)... I suspected it was arthropleura armata but I wasnt really sure and so I got an ID from an expert who confirmed it was.... and this stuff isnt common so I wanted to do it some justice... after carefully looking at it for a while and checking the seperation layer seemed to continue under the still attached rock on the negative, I decided to guess the boundaries of the fossil and cut into the nodule creating 'square faces' that I could use for 'purchase' to chisel from and hopefully lift the rock away containing the fossil and then re-attach the bits back onto the positive.... and tidy it all up.... It was a gamble but it paid off... it worked a treat...

If you look at the images you can see how it was before I started work on it... The red lines indicate areas that I cut into the nodule using a die grinding stone, to create the required vertical edges to chisel from... without doing this the chisel would just of slipped or maybe a hammer blow be deflected into following the wrong path of fracture.... to ensure the chisel was sharp enough for the job I used a wood chisel with a very fine edge to direct the force where i wanted it.... and once each section was lifted away I carfully glued it in place on the positive using superglue....

Arthropleura armata ....Westphalian in age

In conjuction with a UK carb expert we determined this is part of a specimen that was around 1.8 - 2 metres in length and seeing they were considered vegetarian he suggested... '' that would do some damage to your cabbage patch''....

[glacialerratic]

Amazing find and great prep/restoration work!

Thanks for putting this thread up -- very informative.

Do you know if there's ever been an articulate Arthropleura found? Or are all the finds pieces, reconstructed?

Truly an awesome arthropod!

[Terry Dactyll]

michigantim..... I agree, I love it to.... Just a quick google on the web shows very little 'actual fossil material' about.... although this looks a fair chunk of one below....

http://bestiarium.kryptozoologie.net/wp-content/uploads/2009/08/Arthropleura-armata-Saarland-1024x768.jpg

and

http://www.yale.edu/ypmip/taxon/arthro/36259.html

I would imagine with the animal having a large bodymass and conditions (rainforest-like) with the humidity of the enviroment it begain to break down and decay very quickly after death, so finding any pieces at all is quite a rarity..... mainy you see reconstructions.... some more convincing than others.... this one is my favoroute....

http://www.geology.cz/aplikace/fotoarchiv/sobr.php?r=700&id=14570

Heres another bit I found..... a leg in a siderite nodule....