Uncle Siphuncle Posted June 30, 2010 Share Posted June 30, 2010 (edited) I ran up to Cincinnati last weekend to party with 55 of my old high school friends for my 40th birthday. In between festivities I managed to slip in some impromptu fossil collecting time. I enjoyed making a number of good finds including the crinoid crown in the attached image. I think it may be Pycnocrinus dyeri. I'm not even sure what formation I was collecting but it is Ordovician. The rock seems a little too hard to blast down with baking soda. The way the matrix is humped, there is a good chance that the arms may be splayed out below the surface of the matrix. What is the best way to prep this specimen without damaging it? How best to explore for arms? Scribe? Then what blaster media? Hard media would would wipe out detail and give it a strange sheen. Would KOH work on a specimen like this? I may try a little on the corner of the matrix as an experiment if I hear no comments on this. All replies welcome. Edited June 30, 2010 by danwoehr Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
MikeD Posted June 30, 2010 Share Posted June 30, 2010 That looks incredibly promising and cool. Ask "cousin it" for advice as he has extensive experience with Ordovician crinoids. Link to comment Share on other sites More sharing options...
jpc Posted June 30, 2010 Share Posted June 30, 2010 KOH? Have you used this before? I have been told about it by guys in Switzerland but never used it. Someone even gave me a small amount once. Can you tell us about usinh KOH? As for your crinoid, do you think dolomite owuld be bad for it? I'm just asking... I have zero experience with crinoids and very little exp with Cincinatti fossils. Link to comment Share on other sites More sharing options...
tracer Posted June 30, 2010 Share Posted June 30, 2010 don't know if the surface on the back or somewhere is of similar texture, but i would experiment on the back probably using dolomite. i would definitely not use koh. if i found that i could remove a relatively thin layer with the air abrasive and have it look ok across the matrix, then i'd start at the exposed edges and carefully work outward, taking years if necessary to do it right, trying to channel x-man and his megafish exploits. dedicate as much time and effort as possible to getting this thing right. it's a cool fossil. to all you other san antonio area hunters - you're welcome Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted June 30, 2010 Author Share Posted June 30, 2010 I took another spectacular crown as well as 18 perfect Flexicalamene trilobites...not bad for a weekend I didn't even plan to collect. Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
tracer Posted June 30, 2010 Share Posted June 30, 2010 flexicalymene is one of the few formal names i find cool and amusing. but exogyra is still my favorite. Link to comment Share on other sites More sharing options...
seanm Posted June 30, 2010 Share Posted June 30, 2010 I agree with Tracer on this one. One other thing you can do when the matrix is hard and you are worried about damaging the fossil is to mask it as you are going along. Mix a little latex rubber with some talcum powder and paint on to the areas you have already prepped and allow to dry. By doing this you will not over abraide any areas that you have done already. Keep doing this as you prep it (takes longer as you have to wait for it to dry) and when you are all finished you can simply peal of the masking. Sean Rock kickers of the world unite Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted June 30, 2010 Author Share Posted June 30, 2010 Good thoughts.... Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted June 30, 2010 Author Share Posted June 30, 2010 And Tracer my favorite as a 5th grader flipping through fossil books was always Scaphites quandrangularis nodosus Meek....(no joke) Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
Auspex Posted June 30, 2010 Share Posted June 30, 2010 And Tracer my favorite as a 5th grader flipping through fossil books was always Scaphites quandrangularis nodosus Meek....(no joke) "Mucrospirifer mucronatus"... Made my young mouth do funny things "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
tracer Posted June 30, 2010 Share Posted June 30, 2010 "Mucrospirifer mucronatus"... Made my young mouth do funny things <handing auspex a tissue> here, wipe that mucronatus off your nose... Link to comment Share on other sites More sharing options...
Crinoid Queen Posted June 30, 2010 Share Posted June 30, 2010 That is beautiful. I only use dental pics and a tooth brush to work on mine. I start from the calix and work my way up along the arms keeping the pic flatand then using a fine wire brush to expose the fine detail at the finish. Nice find! Good luck Prepping it! Link to comment Share on other sites More sharing options...
pleecan Posted June 30, 2010 Share Posted June 30, 2010 (edited) Too increase the cutting power of air abrasion ... one can increase the air pressure with the baking soda or go with a smaller diameter nozzle. Having maxed out, one can try mixing various ratios of harder media ie (aluminum oxides or SiC )with the baking soda... try 5%, 10%, 20% aluminum oxide with the baking soda to incremental increase cutting power of the blasting medium. PL Edited June 30, 2010 by pleecan Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted June 30, 2010 Author Share Posted June 30, 2010 I suppose during the hurricane this week I can do a little prep work! Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
ashcraft Posted June 30, 2010 Share Posted June 30, 2010 The crinoidsI have prepped have been silicic, so I use acetic acid and a tooth brush to find the general lay of the arms, then blast or remove with a scribe depending on the amount of material needed. Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
crinus Posted July 1, 2010 Share Posted July 1, 2010 I got a personal request for my input on this subject so here goes. I use two tools when I prep crinoids. Air abrasive machine and air scribes. I use powdered limestone (similar to powdered dolomite, but cheaper) as my media and control the cutting by pressure and powder flow. If you have a Crystal Mark machine, you can control both. For the scribe I use the ARO type of scribes and NOT the CP type. I would start air abrading somewhere near the calyx and only use the air abrasive machine until I locate an arm. Once you know the depth of the arm you can then begin using the scribe and go back and forth between the two pieces of equipment. It will be a slow process. You cannot scribe everything and then switch to the air abrasive machine since the depth and position of the arms can change. It is easy to damage the arms if you do not know where they are. I once did a series of pictures of cleaning a crinoid. I can post those here. There are about 20 pictures. Basically it would show the back and forth between the two tools. If interested, I can resize the photos for posting them here. BTW. Very nice crinoid and it isn't even cleaned. I suspect that it will be a spectacular specimen. It looks like it will be in the starburst pattern. There are a several starburst pattern preserved crinoids on my web page if you are not sure what I mean by starburst. crinus Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted July 1, 2010 Author Share Posted July 1, 2010 Thanks Crinus....I'll employ the techniques mentioned. I have an ARO scribe as well but don't use it often as it seems a bit fickle. It tends to cut in and out as the accumulator pressure fluctuates between extremes, and this is a 20 gallon tank. Have you had similar issues with your ARO pen, and if so, have you made any adjustments to make it run continuously? Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
crinus Posted July 1, 2010 Share Posted July 1, 2010 Thanks Crinus....I'll employ the techniques mentioned. I have an ARO scribe as well but don't use it often as it seems a bit fickle. It tends to cut in and out as the accumulator pressure fluctuates between extremes, and this is a 20 gallon tank. Have you had similar issues with your ARO pen, and if so, have you made any adjustments to make it run continuously? Yes, the ARO does not work well below 100 psi. If your compressor does not come back on until you are below 100 psi you will have problems. You need a compressor that kicks back on above 100psi. I called the repair service for my compressor and explained the problem. The tech guy told me what I need to do but he also indicated that was illegal. Basically what he told me to do shifted everything over and now my low point is 100psi and my high point is about 150 pst. Compressor was not rated for 150psi. It had been about 10 years since I did that and the compressor is still working fine. You also have to remember to make sure the ARO is oiled. I assume you are putting oil into you air line. crinus Link to comment Share on other sites More sharing options...
MOROPUS Posted July 1, 2010 Share Posted July 1, 2010 <handing auspex a tissue> here, wipe that mucronatus off your nose... The stranges I`ve ever found on books, is the ammo Parawedekindia Arduennensis.Try to say it faster and louder! And another I like, is the echie Disaster Granulosus. Link to comment Share on other sites More sharing options...
crabfossilsteve Posted July 1, 2010 Share Posted July 1, 2010 I work on crinoids also and I would reiterate pretty much what Crinus said. I'd recommend dolomite or limestone and adjust the pressure and flow of the abrasive till you get the right mix and aggressiveness. Yeah start at the calix and work out. Work slowly and you should get a very nice display. Also agree that the Aero can be finicy and you need to keep it cleaned and oiled, but it is an excellant tool. Good Luck Crabfossilsteve Link to comment Share on other sites More sharing options...
cousin it Posted July 3, 2010 Share Posted July 3, 2010 [Ca,Mg]CaCo3 not a good medium. If you use it, keep your angle of attack very low. Better to use NaHCO3, and then rely on a scribe, or pen vice. http://soliussymbiosus.wordpress.com/ Link to comment Share on other sites More sharing options...
Recommended Posts