Tagged: @rleder @robertross @jkallmeyer
March 11, 2016 at 10:03 pm #3417
I re-read the paper you gave us but I interpret it differently. The authors say they used “Rewoquat, a 75% solution of ….” So I read that as the Rewoquat itself is a 75% solution of the active ingredient. When they talk about using it later in the paper they just say they use Rewoquat with no indication of dilution. At least that’s the way I read it.
I don’t know what Rewoquat looks like but the material that Mathew is finding that is supposedly “equivalent” is quite viscous so that further dilution will be necessary. I hoping that Ronny @rleder will get back to us about Rewoquat dilution when he returns from his travels in Germany.
JackMarch 14, 2016 at 1:12 pm #3425
Hey guys,@jkallmeyer, @john-christian,
you can use Rewoquat diluted with Isopropanol up to 20% but the results are way better with the full strength. Like I said it is just a very high concentrated detergent (tenside) similar to the one used for laundry but much higher concentrated. The more you dilute it the worst it works. A good thing is that you can reuse it several times what reduces the costs dramatically. Just let the Rewoquat-sediment solution rest till the sediments sink down. Than you can decant Rewoquat and use it again 😉
RonnyMarch 14, 2016 at 1:18 pm #3426
Ahhh ,@jkallmeyer, @john-christian, I forgot to mention that it is not biodegradable and ecologically harmful in it’s original high concentration. But you can release it very low concentrated with water. Just make sure that you reach a similar concentration like with laundry detergent (like I said it’s the same just higher concentrated. One last thing: Rewoquat is inflammable and you should wear rubber gloves and protection glasses while usage.
cheers from Germany
RonnyMarch 14, 2016 at 4:08 pm #3430
Thanks, your posts on Rewoquat were very helpful..
JackMarch 15, 2016 at 12:02 pm #3437Matthew SpeightsParticipant
Thank you for the information. I got the sample last week, so will start testing once I get the time. The equivalent of Rewoquat available in the USA is an approximately 90% solution, so it is much thicker than the 75% solution available in Germany. Its viscosity is something between that of very cold honey and petroleum jelly, so I will have to dilute it somewhat with isopropanol.March 16, 2016 at 10:57 pm #3493
I am a huge fan of preparation and have been learning steadily for several years. I want to encourage people to continue to share tools and techniques for those of us that are amateurs. However, some amateurs are more advanced than you think. For example, fossil prep is my hobby, but I have a nice dissection microscope with 5MP camera that is the BEST tool I own for prep. Large or small, everything I prep goes under the microscope. Is it wrong to love high-end optics? I also have a dual tank Comco air abrasion unit and 3 PaleoTools airscribes (Paleo ARO, ME-9100 & MicroJack 3). I have an 80 gallon compressor with an Ingersoll Rand Thermosorb Air Dryer and high-end desiccant dryers. I also have the big Comco vacuum system that connects with the large work cabinet. I use Butvar and the gamut of Paleo Bond adhesives and I am experimenting with diluted vinegar, but I want to learn more. Not having a knowledge source readily available, I am hoping the experts do not hold back by assuming amateurs only have rudimentary tools. Prepping is a passion and I am fully invested.
Jon CartierMarch 17, 2016 at 2:23 pm #3498
Hey Jon (@jon-cartier ), it is good to have posts like yours. Yes we know that some amateurs have very professional equipment, sometimes even better than most of the museums. We are definitely not assuming that amateurs have rudimentary tools. But some amateurs might appreciate that the more experienced folks share their knowledge and it does”t matter if the recommendations come from vocational or avocational paleontologists. What matters is the fact that we share and learn together to reach the best level of practice. Please tell us more about your experiences, even after decades of being a professional paleontologists we still can learn something knew. We really appreciate your input 😉
all the best
RonnyMarch 17, 2016 at 10:55 pm #3551
@rleder – I am totally on board with that. I have many friends interested in prep work who span the spectrum from novice to advanced and everything in between. I just want to encourage the pros to share what they know. : )
JonMarch 26, 2016 at 3:14 am #3617
Some of the Mosasaur teeth that come straight out of the North Sulphur River are extremely brittle. Sometimes they come out fine in the matrix but most times the teeth are extremely fractured and explode when removed. Putting PaleoBond Field Consolident or diluted white glue on the fossils prior to removal is helpful if the matrix is dry, but in the lower levels where the Ozan layer is, is often constantly very wet during the prime hunting seasons.
If you get a tooth that exploded into cubes when removed despite your best efforts, here is what I do.
1. I wrap the wet broken pieces in heavy aluminum foil. sometimes to keep it stable and not make it worse, I will collect a handful of fine grain mud and pack it around the pieces after soaking it in white glue or PaleoBond Field Consolident .
2. When I get home and let it dry out, I get it under good light and my dissection microscope. Any magnification is better than none. I take the largest free piece of tooth enamel and soak it with low viscosity PaleoBond penetrant stabilizer. (40CPS). I soak up extra glue with a rolled up section of paper towel so it does not create thick glue areas that prevent the pieces from fitting back together. Once it dries, I clean all surfaces with the tip of a new Exacto blade. it makes cleaning inside each of the vertical tooth grooves much more manageable. The thin layer of glue will peel off the enamel without too much trouble and it even helps lift some of the dirt and sediment from the exterior enamel of the tooth.
I repeat this process with each piece of the tooth, cleaning and stabilizing each one at a time. as I find sections that fit together, I test fit and work them to fit as tightly together as possible. Then I will use the penetrant stabilizer to glue them together. many of the pieces are as small as 1 mm.
Over time the pieces assemble into a tooth that is all or mostly complete.
I have enclosed a few pictures of an exploded Tylosaur Mosasaur tooth from the Ozan in the North Sulphur River and the progress toward a reassembly.
Jon CartierMarch 26, 2016 at 4:41 am #3621
Black Cat Mountain Trilobite
I had the pleasure of getting to spend some time with the famous Bob Carroll, the sole lease holder of the Black Cat Mountain (BCM) trilobite site near Clarita, OK. His shop is filled with homemade tools and techniques learned over a lifetime of prepping JUST Trilobites from this one Quarry. He is not just talented. he is a Michaelangelo with Trilobites. He allowed me to ask questions and even capture a bit of video so that I could study and practice working BCM Trilobites. Bob is a very kind and generous guy and I really appreciate his willingness to share some time with me.
I studied what he showed me and practiced on scrap trilobites for 3 years before I was brave enough to show him some of my work. I am still not near what he can do, but I am definitely getting better. Here is a sample of working a BCM Trilobite and my technique.
I start with air scribes to take off the big matrix and expose the outline of the trilobite. Getting too close to the trilobite will cause damage, so the airscribe work must be slow and under magnification. the trilobites are typically one inch or less long. Stop with the airscribe once the edges are exposed.
Next I move to swivel pin vices and dental picks sharpened on diamond grinding stones. I pick at an exposed side and uncover the entire Trilobite a little at a time. Once it is exposed, I work the landscaping around the base of the trilobite to give it a surface that makes it look living.
After I have the Trilobite exposed and roughly landscaped, I start on the cleaning of the surface. It is challenging to avoid damaging the fine features on the surface of the shell. I have tried several methods, but I do not turn to air abrasives until I absolutely cannot get any more matrix off with the Exacto tip. Under magnification, I pick and chip off as much matrix as I can, working deep into the segments and around the dermal bumps trying to avoid scratching the surface. As soon as I have as much matrix off as possible, I turn to the air abrader. I only hit the surface of the Trilobite in very short passes and check to ensure I am not burning through the shell. You can tell you are burning through the shell when it starts turning lighter color. it is only the width of a few sheets of paper in many areas. The eyes are especially thin and fragile. be extremely careful here to avoid damage. Also the base of the axial lobe down the center of the thorax is challenging to clean.
Once the trilobite is clean, I finish landscaping and present.
Jon CartierMarch 26, 2016 at 4:48 am #3626
Here are a couple more pictures. I do not have a picture of the final form, but the last picture below is the completion of the pick work – right before the air abrasion. I use 50 micron Sodium Bicarbonate on this matrix. occasionally, I will mix in a little Aluminum Oxide if the matrix is too hard.
JonMarch 26, 2016 at 11:05 am #3630
Hey Jon (@jon-cartier), pretty impressive job! Thank you so much for sharing your experience in preparation with all of us. That is exactly what this is all about.
all the best
RonnyApril 14, 2016 at 10:56 pm #4358
I just finished uploading a number of fossils to the “Fossils” page here. They are all cut and polished specimens that show the internal structures of various fossils. I do this myself but didn’t know if my methods would be of interest or appropriate for this forum. Check out those posts and if you think this would be of interest let me know.
JackApril 15, 2016 at 9:25 am #4359
Hey @jkallmeyer, you do this with equipment you have at home? That definitely is of interest since most of the technical equipment for cutting and polishing hard rock is quite expensive and also easy to ruin if you don’t know the proper handling. I have cut and polished hundreds of agate and fossil ammonites for museum events in Germany as give away. It is not as easy as it seams even with the right equipment. So once again, yes we are very interested in your setup and technique.
RonnyApril 15, 2016 at 5:19 pm #4361
I have a number of specimen photos posted on the Fossil page here that are cut and polished by hand (one shown below). Primarily, the specimens shown are calcitic and are relatively soft. One specimen is silicified. My methods are labor intensive but fairly easy to do.
1) Unless you collect a specimen that is fairly flat to begin with, you will need to cut the specimen (or have someone else cut it for you).
2) I use an old Felker Di-Met diamond saw. This is a contractor’s saw with a 1 HP motor. The blade is a Black Diamond brand, 12″ diameter which will allow up to 155 mm maximum cut depth. I use water from a garden hose through flexible nozzles to lubricate during the cutting. I have the saw on a roll around table and I use it outside as water sprays everywhere under use. The saw has a sliding table but no vise. I installed a lip on the back side to help guide the material into the saw. See photos.
3) Tile cutting saws are available fairly inexpensively at big box stores. These saws are designed to cut marble and other stones as well as ceramic tile. The stones being cut are all fairly thin so the motors on these may be underpowered for cutting thick materials. My saw had a 1/3 HP motor on it when I first acquired it and I was able to make that work by slowing down the progress into the blade by not pushing as hard. This could also work on the smaller tile saws.
4) Diamond saw blades are expensive so a saw with a vise is best to stabilize the specimen. This will also give a smoother cut. As I said, mine has no vise so I go to great effort to make sure I can hold the piece steady throughout the cut. If you wiggle the piece you can bend and ruin the blade.
5) All of my polishing is done by hand. I do not own any type of lap at this time. I use automotive wet/dry finishing paper for all but the final stage. All papers that I use are wet and then placed on a 1/2 inch thick piece of Lexan that I have propped on an angle in a utility sink (I’ve also done this outside while sitting on a lawn chair with the Lexan in my lap). I use these grits of paper: 100, 220, 320, 400, 600, 800, 1000, 1200 and sometimes 1500 and 2000.
6) I start with 100 grit paper to get out the saw marks and make the piece flat. This is the most time consuming part of the process. It is a matter of scrubbing the surface against the paper. The paper is kept wet as needed. Any time the piece is lifted off the paper to inspect progress, the paper must be rinsed off before placing the piece back on the paper. This step removes any tiny chips that could be trapped under your specimen when you start sanding again – this would put a big scratch in your work and cause you to start all over. Always rub the specimen in one direction only so the scratches you are putting on the specimen from the sandpaper can be distinguished from the scratches already on the specimen. Examine the surface with a 10-x hand lens to be sure all sanding marks are going in the same direction over the entire surface of the piece. Once this is accomplished, switch to the next finer grit paper and turn the specimen 90 degrees before starting to sand so the new scratches can be distinguished from the previous. Continue this process all the way through to the finest paper you are using. Be very careful to keep the specimen flat during this process so it doesn’t rock and make the surface rounded or beveled.
7) For a final polish, I use Cerium Oxide abrasive powder on a wet 1/4 inch thick white felt pad. The pad is placed on a 1/2 inch thick Lexan piece for support. This is a rubbing process just like the sanding although your motion can now be circular or linear. Always inspect the pad for tiny rock chips that may flake off your specimen as they will absolutely ruin all of your work.
8) This process works very well for any specimen that is calcitic. On small specimens the sawing can even be skipped. Specimens that are Dolomite can be done too but it requires a bit more elbow grease as they will be harder. Silicified specimens are tough as they are considerably harder and not really practical to do by this method.
9) A four inch diameter specimen will take about 2 hours from start to finish using this method and it’s a great workout for you arms!.
10) The silicon carbide wet/dry paper can be obtained at automotive finishing suppliers except for the 100 grit. I get that and the Cerium Oxide from Kingsley North (they deal in lapidary equipment and supplies).
11) Note that not all specimens will exhibit a mirror finish. That depends on the grain structure of the specimen. Some are fine grained and solid while others are coarse grained and porous. Either way, the internal structures of some fossil can be beautiful and help with identification.
JackApril 17, 2016 at 10:48 pm #4379
Hi Ronny @rleder
and Matthew @matthew-speights –
Here are some action shots of wet sawing a silicified stromatoporoid. This took longer than it should have. My estimate of time, had I not encountered an issue, would be about an hour. Two action photos attached plus one of the cut surface. The internal structures are somewhat visible in this photo. Polishing will make this spectacular.
JackApril 19, 2016 at 3:07 pm #4386
Hey Jack @jkallmeyer, that is a very impressive tool and your home lab is very well equipped, respect for that. Your saw reminds me of the saw I was using at the stone prep lab at the University of Leipzig, even if we had some more safety features and regulations (like plexiglas shield etc.) and cutting free hand was a no go 😉 I always had to fix the stones (it took ages) on a slide with automatic propulsion. That way the cut was always straight and smooth and no chance to ruin the blade. The blade diameter was almost 20 inch (50 cm) and I had another monster saw with a huge motor and a 30 inch blade for big blocks. The speed of the smaller one was stepless adjustable and best for cutting all kind of stones (soft and very hard), even agate. For polish I used cilicium carbid powder or Coferpol polish powder (mixture from Al2O3 , Cr2O3 , SiO2) on a glass plate. And then looping with not to much pressure till the agate shines 😉
We also let kids polish agates at special family museum events. First we cut the agate nuggets, then we glued them back together with hot glue. The kids had to split the nuggets and polish them with the powder. After finishing they could take the shiny agates as a gift home and their parents could give us a donation if they like. That was always a lot of fun.April 19, 2016 at 9:30 pm #4389
Oh yeah, safety. I should have mentioned the lack of a belt guard and you picked up on the other areas of concern. I do have the belt guard but it will not fit over the current drive set-up. This saw was originally the student saw at UC. It had fallen into disrepair and UC has no equipment maintenance staff so I was able to acquire it. The OEM original motor, pulleys and belt were missing having been replaced with a small motor and V belt drive. When I upgraded the motor I went with a more robust drive belt – I did not go back to the OEM drive because of cost. Anyway, I am not near the drive when operating the saw. I would love to have a Plexiglas splash shield but since I have to push the specimen it would get in the way so I just get wet. This saw never had a drive system to move the specimen as it is basically a heavy duty tile saw. The sliding table does have holes in it to attach a potential vise but I have none to attach. Cutting “flat” specimens is not too much of a problem. Irregular shapes like the stromatoporoids though can be interesting.
In your explanation you mention some polishing materials. It sounds like you are able to take a specimen from cutting directly to polishing. Is that right? What grit size are these materials?
JackApril 20, 2016 at 11:16 am #4390
Hey Jack (@jkallmeyer), very smart of you to acquire that saw from UC. I have seen a lot of technical equipment like intact microtome, microscopes, stone saws or whole lab facilities been thrown away just because the Professor who had purchased it from his fundings left the University and the new Professor had no use for it or simply disliked the color of the furniture or the brand of the equipment. That was always super frustrating to see how tax money was wasted. I also think that especially the machines build in the 60s or 70s are of much better quality, build to last forever. I was able to rescue and store some nice tools from being carelessly discarded. For example a very nice ultra microtome. Answering your question about polishing, we used COFERPOL UG and here is the data sheet from it’s website:
Polishing- and Abrasive compound on basis of surface optimized metal oxides
COFERPOL UG is the better substitute of Cerium Oxide.
Polishing- & Abrasive Characteristics
best surface quality
high abrasive power = fast polishing (50% faster than Cerium Oxide)
high shape and and heat stability
Al2O3, Cr2O3 , Si2O : min. 98 %
Particle form: spherical
Predominant particle size: ~ 0,3 micron
Density: 5,2 g/ml
No dangerous cargo
Not regarded as hazardous waste, as defined by EU Directive 91/689/EEC
Advantage of raw materials and location
Manufactured synthetically in Germany by large-scale production
CERIUM OXIDE SUBSTITUTE COFERPOL UGCofermin Chemicals GmbH & Co. KG
GermanyApril 20, 2016 at 9:21 pm #4393
That COFERPOL UG sounds great but not available in the US. Next time you are in Germany maybe you could bring back a kg for me 😉
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