steelhead9 Posted January 11, 2011 Share Posted January 11, 2011 All great advice about removing it, but I would liberally soak it with a penetrant/stabilizer such as paleobond or starbond. This will seal all the cracks and stabilize the matrix before you attempt to remove it. good luck! Still Life Fossils Link to comment Share on other sites More sharing options...
dougbugs Posted January 11, 2011 Share Posted January 11, 2011 I have been using a gasoline powered concrete saw with a diamond blade for over 30 years (I like the Stihl brand). It weighs about 30 pounds but I would be lost without it. I am too lazy to pound away with hammer and chisel for hours on end. Most things, even in hard limestone, can be cut out in less than 5 minutes. Of course there is still no guarantee that it is going be extracted exactly the way you want it. Sometimes there are cracks in the rock or fossil that are impossible to see. If the fossil is composed of many small plates (I am thinking crinoid or echinoid) I sometimes cover the fossil with mineral tack or modeling clay to keep the pieces from being vibrated apart and lost. Before you start sawing, you want to make sure that you have searched the immediate area for other fossils. Once you begin cutting, the surrounding rock gets covered with dust and collecting becomes impossible. Very dusty but very effective. I guess you could cut down on the dust if you used water for a coolant. I never have this luxury. I am sure that you can rent these saws at most rental places. Link to comment Share on other sites More sharing options...
Wrangellian Posted January 12, 2011 Share Posted January 12, 2011 I have been using a gasoline powered concrete saw with a diamond blade for over 30 years (I like the Stihl brand). It weighs about 30 pounds but I would be lost without it. I am too lazy to pound away with hammer and chisel for hours on end. Most things, even in hard limestone, can be cut out in less than 5 minutes. Of course there is still no guarantee that it is going be extracted exactly the way you want it. Sometimes there are cracks in the rock or fossil that are impossible to see. If the fossil is composed of many small plates (I am thinking crinoid or echinoid) I sometimes cover the fossil with mineral tack or modeling clay to keep the pieces from being vibrated apart and lost. Before you start sawing, you want to make sure that you have searched the immediate area for other fossils. Once you begin cutting, the surrounding rock gets covered with dust and collecting becomes impossible. Very dusty but very effective. I guess you could cut down on the dust if you used water for a coolant. I never have this luxury. I am sure that you can rent these saws at most rental places. You can use a diamond blade with one of these saws, and without water? I'm glad to hear that. I spent what I consider a lot of money on a masonry saw just to find out that the masonry blades don't seem to work very well - they immediately overheat and melt the rock, even with a hose aimed in there to cool it, and yet take forever to get thru a piece. I know the diamond blades don't have this problem but I never got around to seeing if I could use one on that type of saw, and without water. I understand they may not last as long without water but that's a price I think I can afford to pay.. Link to comment Share on other sites More sharing options...
dougbugs Posted January 12, 2011 Share Posted January 12, 2011 You can use a diamond blade with one of these saws, and without water? I'm glad to hear that. I spent what I consider a lot of money on a masonry saw just to find out that the masonry blades don't seem to work very well - they immediately overheat and melt the rock, even with a hose aimed in there to cool it, and yet take forever to get thru a piece. I know the diamond blades don't have this problem but I never got around to seeing if I could use one on that type of saw, and without water. I understand they may not last as long without water but that's a price I think I can afford to pay.. Yes, you can definitely use a diamond bladed concrete saw without water. The blade will not last as long without coolant, but I can get a few years worth of cutting out of one blade. The length of service depends a lot on what type of rock you are cutting. I use my saw a lot to trim matrix and cut down the size of the slab after I have prepped the fossil. A word of caution - The saw and the rock can get quite hot so be careful when you pick up the fossil that you sawed out. Link to comment Share on other sites More sharing options...
Scylla Posted January 12, 2011 Share Posted January 12, 2011 Using a saw dry will cut down on your useful lifespan too from inhaling the dust. Link to comment Share on other sites More sharing options...
tracer Posted January 13, 2011 Share Posted January 13, 2011 there are a number of methods of making diamond blades and they vary dramatically in cost and performance, and some would be very unsuitable for using dry, and potentially dangerous. it is really annoying to pay big bucks for a saw blade, but sometimes it's the way to go. link as for stabilizing the rock in situ before sawing, i'm ambivalent on the methods. pouring a bunch of brand-name ca glue on specimens will jack the cost quite a bit over time of collecting them. and that concept is really most suitable for people who have air abrasive prep tools to remove all the bonded dirt and matrix and excess ca from the extracted fossil. i have been known, however, to put a soft cloth over a fossil and put light hand pressure on it when banging away with a rock hammer or when using a pneumatic illinois near it, cuz dampening vibration will at times keep something from leaping loose undesirably. (that's really kinda important when mining crystals, by the way. they like leaping loose.) Link to comment Share on other sites More sharing options...
Wrangellian Posted January 13, 2011 Share Posted January 13, 2011 I am mostly working with shale so I think a saw will last longer dry than on eg. sandstone, which I dont mind cutting wet anyway - it's the shale I need to keep water away from otherwise it crumbles and splinters like it's going out of style. I need to learn more about the different diamond blades or any kind of blade that will cut sedimentary rock effectively when used dry. I have a small thin diamond blade for my Dremel and the cuts I've made with it so far do not noticeably heat it up. Maybe larger blades on larger rocks will create more heat, I dunno. As for stabilizing, I assume by "ca" you mean cyanoacrylate, Tracer? I bought a tube of 'Paleobond' before I learned it is essentially crazy glue, and then I learned furthermore that 'ca' degrades in the presence of moisture, or at least turns blue, but in any case a change can't be good for the long term usefulness of the product. (I want my fossils to stay bonded once I've bonded them to my satisfaction!) I've been using diluted WeldBond for my shale fossils and I've had no complaints about it so far but I've heard complaints from others. I just hope it doesnt cause problems when I go to trim it, as I can't avoid having to stabilize first, then trim. Link to comment Share on other sites More sharing options...
tracer Posted January 13, 2011 Share Posted January 13, 2011 i'm not sure what's in the product that you mentioned, so can't comment on it. if what you're stabilizing *has* to be stabilized, then the decision is easy. i was talking about putting cyanoacrylate glue on a dirty fossil in hard matrix as being something i would have second thoughts about doing if i didn't have a good way to get it off the surface later. plus the stuff can be like forty or fifty dollars a bottle for some brands in a larger bottle. and by the way, if you've never tried to mess with a large bottle of thin cyanoacrylate glue, i can tell you that you will be rapidly and unforgettably punished for any unsuave technique in using it. it gets quite hot as it rapidly sets in the presence of moisture, which, unfortunately you contain, sooo... Link to comment Share on other sites More sharing options...
Wrangellian Posted January 13, 2011 Share Posted January 13, 2011 i'm not sure what's in the product that you mentioned, so can't comment on it. if what you're stabilizing *has* to be stabilized, then the decision is easy. i was talking about putting cyanoacrylate glue on a dirty fossil in hard matrix as being something i would have second thoughts about doing if i didn't have a good way to get it off the surface later. plus the stuff can be like forty or fifty dollars a bottle for some brands in a larger bottle. and by the way, if you've never tried to mess with a large bottle of thin cyanoacrylate glue, i can tell you that you will be rapidly and unforgettably punished for any unsuave technique in using it. it gets quite hot as it rapidly sets in the presence of moisture, which, unfortunately you contain, sooo... I'm trying to think if there are any other reasons why I dont use that stuff... let's see: turns blue with moisture, sticks best on skin, then burns.. goes everywhere but where you want it to go... I dont think it sticks very well in the presence of h2o, it seems to me it didnt bond damp shale very well when I last tried. Link to comment Share on other sites More sharing options...
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