Doctor Mud Posted May 24, 2015 Share Posted May 24, 2015 Well, I'd been working on a little fella. A small Tumido crab a bit bigger than RJBs Tiny Tim. But things got fiddly (crushed legs) and a tad sticky (matrix won't flake from the shell nicely), so I thought I would have a break and work on a larger specimen, Everything went well, despite the rock being the hardest I've worked with yet (it blunts tungsten carbide styli in a day's session!) I worked my way down to shell and everything was dandy. Well then things got sticky. This is when the matrix doesn't flake off nicely from the crab shell. You have to work closely to the shell and almost grind down to the shell. I tried working under the scope and I can see that the problem is caused by calcite crystals that grow into the shell and the matrix, binding the two together. I managed to tickle some off under the scope with a micro jack but I'm stuck now. I even tried making a window to the left to work my way back. But also very sticky. I wonder if an air abraded would be the best option here. I don't have one yet and finances will prevent that happening for a while. Comments and suggestions welcomed! The concretion is about 15 cm across. It will be quite "leggy" on the right hand side and I can see the tips poking out. This was found on the same day near 6ixes "weeping concretion" 1 Link to comment Share on other sites More sharing options...
Doctor Mud Posted May 24, 2015 Author Share Posted May 24, 2015 Thanks so much for this great information TriloAnt. I was thinking an air abrader might be the way to go, but hoping there might be another option. I've had sticky crabs before, but nothing like this. I have been able to tease off tiny chips under the scope but here I just get right down to the shell with the matrix still holding on for dear life! Funny that half prepped nicely. I normally find the top is always somewhat sticky and the rest is ok. That's why I tried making the test window on the left. I might have to put it aside until I am in a position to set up for air abrasion. Building a blast cabinet would be a good way to go for cutting down dust and flying rock chips with scribing too. I have a prep booth I made that could be easily modified. All I would need is some sort of dust extraction system. I see there is a great thread for a"poor mans" air abrader set up here on TFF and it suggest a shop vac. I have been thinking of getting some sort of pneumatic chisel. The Tumidocarcinus concretions can be large so there is a lot of bulk matrix removal to do. Link to comment Share on other sites More sharing options...
RJB Posted May 25, 2015 Share Posted May 25, 2015 Hey Doctor Mud. looks to me like your doing a super good job with that crab. Im just wondering how much time you have in it so far? RB Link to comment Share on other sites More sharing options...
Doctor Mud Posted May 25, 2015 Author Share Posted May 25, 2015 Thanks RB. I'm really happy with what has been exposed. I really like the colours and the preservation is excellent. I put a couple of days in so far, so 16 hours ish. To start it was quick, but things slowed to a glacial pace once I entered stickyville. Sometimes I wonder if finessing at low power can make life more difficult with sticky crabs and more power is needed to separate shell from matrix. I guess then there is the danger of shell peeling off as well. Link to comment Share on other sites More sharing options...
RJB Posted May 26, 2015 Share Posted May 26, 2015 You've got more patience than I Doctor Mud. I would not put in that kind of time for stickiness. I simply don't have the patience for it. Like Trilo says, "slow and steady". RB Link to comment Share on other sites More sharing options...
Doctor Mud Posted May 26, 2015 Author Share Posted May 26, 2015 (edited) Thanks guys for the words of wisdom and support. I agree totally. I've tried approaching at higher power and the matrix just won't budge. You end up with several mm of caked on matrix. I know RB - it's a battle of will power to keep it up. If I had lots of crabs I wouldn't bother with the micro surgery, but these Tumido concretions are hard to come by. Some days I find none and I only get to visit a couple of times a year. I've decided to put this guy aside until I can set up for air abrasion. It looks like it will be really nice and I don't want to ruin a great specimen. I just can't get the matrix to budge anymore with the scribe without damaging the shell. I'll focus on my smallest one for now. It's working out well. Edited May 26, 2015 by Doctor Mud Link to comment Share on other sites More sharing options...
6ix Posted June 25, 2015 Share Posted June 25, 2015 Wow, its looking great - some real nice detail there mate! Will you be able to leave it alone? Link to comment Share on other sites More sharing options...
Doctor Mud Posted June 14, 2020 Author Share Posted June 14, 2020 Progress at last! Years ago I hit the wall on this crab. It was sticky, but doable. Then it got super sticky. I thought it was impossible. I recently got a microscope articulated arm for my scope. There was absolutely no seperation of rock from shell on most of the carapace and legs. Just have to go real slow under the scope. With a Microjack. This is my toughest prep yet! Good news is that the front end and pincers are not sticky. 5 Link to comment Share on other sites More sharing options...
fossisle Posted June 14, 2020 Share Posted June 14, 2020 Patience rewarded!! Cephalopods rule!! Link to comment Share on other sites More sharing options...
Doctor Mud Posted June 15, 2020 Author Share Posted June 15, 2020 12 hours ago, fossisle said: Patience rewarded!! Thanks! I’ve never worked so hard on a crab before. You can only flake off mm sized bits of rock or you have to grind down to the shell surface. A scope is essential if you want to preserve the lovely colours and texture of the carapace surface. Link to comment Share on other sites More sharing options...
RJB Posted June 15, 2020 Share Posted June 15, 2020 Very nice job my friend. Glad you got back to this one. Looks like that right back leg is folded back and going to the tippy tippy. Thats gunna make it even cooler. Looking forward to more update photo's. RB 1 Link to comment Share on other sites More sharing options...
6ix Posted June 16, 2020 Share Posted June 16, 2020 Wow - great effort mate! Link to comment Share on other sites More sharing options...
Doctor Mud Posted June 16, 2020 Author Share Posted June 16, 2020 14 hours ago, RJB said: Very nice job my friend. Glad you got back to this one. Looks like that right back leg is folded back and going to the tippy tippy. Thats gunna make it even cooler. Looking forward to more update photo's. RB Thanks Ron, yes my first “yoga” crab. Almost missed that tip in the back leg. Suspected it might be doing that based on the angle of the leg. So was careful while removing rock for the back end. Link to comment Share on other sites More sharing options...
Doctor Mud Posted June 16, 2020 Author Share Posted June 16, 2020 1 hour ago, 6ix said: Wow - great effort mate! Thanks! It’s been a marathon. Very tiring working on such stickiness. Feels longer than it actually has been though. Purposely didn’t count hours, but it’s “only” been 8 sessions at around 5 hours each so about 40 hours. So far. Could be worse 1 Link to comment Share on other sites More sharing options...
crabfossilsteve Posted June 17, 2020 Share Posted June 17, 2020 Yes, those bloody sticky crabs are a pain, but looks like you are coming along quite nicely, Using that microjack can allow you to attack the crab at an extreme angle which can make prepping a sticky crab a little easier. Looking good so far. Link to comment Share on other sites More sharing options...
6ix Posted June 19, 2020 Share Posted June 19, 2020 Dude, I can do about a half hour at a time until previous injuries catch up with me... I remember you telling me how you had 2 electric engravers to swap between them when they got too hot... that's commitment. Link to comment Share on other sites More sharing options...
Doctor Mud Posted June 24, 2020 Author Share Posted June 24, 2020 On 18/06/2020 at 8:40 AM, crabfossilsteve said: Yes, those bloody sticky crabs are a pain, but looks like you are coming along quite nicely, Using that microjack can allow you to attack the crab at an extreme angle which can make prepping a sticky crab a little easier. Looking good so far. Thanks! Looking forward to something a bit easier next Link to comment Share on other sites More sharing options...
Doctor Mud Posted July 22, 2020 Author Share Posted July 22, 2020 Some progress! The only parts that aren’t sticky are the claws and the front of the carapace. I will keep slowly progressing and update you again soon 2 Link to comment Share on other sites More sharing options...
fossisle Posted July 22, 2020 Share Posted July 22, 2020 Coming out beautiful!! Cephalopods rule!! Link to comment Share on other sites More sharing options...
6ix Posted July 22, 2020 Share Posted July 22, 2020 Wow, coming along steadily! Link to comment Share on other sites More sharing options...
crabfossilsteve Posted July 22, 2020 Share Posted July 22, 2020 Yes indeed, looks like you are making progress. I find if you use the microjack and just run it along at a sharp angle along the edge of what you've exposed of the crab you can follow the shell material as appose to coming down onto the matrix. Hope that makes sense. You are just shaving off the matrix from the shell material. Good luck. Looks to be a cool crab. Link to comment Share on other sites More sharing options...
Doctor Mud Posted August 17, 2020 Author Share Posted August 17, 2020 Finally, 5 years after finding it, a break for 5 years, 30 sessions and well over 100 hours......It’s finished! 18 cm across. 2 Link to comment Share on other sites More sharing options...
Doctor Mud Posted August 17, 2020 Author Share Posted August 17, 2020 4 Link to comment Share on other sites More sharing options...
Ludwigia Posted August 17, 2020 Share Posted August 17, 2020 2 minutes ago, Doctor Mud said: Finally, 5 years after finding it, a break for 5 years, 30 sessions and well over 100 hours......It’s finished! 18 cm across. Beautiful!! 1 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Doctor Mud Posted August 17, 2020 Author Share Posted August 17, 2020 Happy with how it turned out! I want an easy one next though - if there is such a thing? Time to celebrate the end of a project with a nice glass of scotch, thanks to everyone for following along and for words of advice and encouragement! Those leg tips on the right were a nice surprise! P.S. the photo of me is before the whiskey It was a long weekend finishing it off. 3 Link to comment Share on other sites More sharing options...
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