dsvilko 12 Posted April 6, 2019 Share Posted April 6, 2019 I have purchased a few small chondrites (mostly an inch or less) and would like to cut them in half and polish the sections. What would be my best option on a tight budget? I have only a standard and drill. Any ideas? If I manage to find a fitting cutting disk (does it have to be diamond?) how do I immobilize the stone for cutting? Quote Link to post Share on other sites
hardtimehermit 512 Posted April 6, 2019 Share Posted April 6, 2019 Hello dsvilko, if i were you i would not try to cut some stones so small. All you need is some wet/dry sandpaper and a nice flat surface, a small mirror or any surface you have that is really flat. Start with 80 grit or 100 and work the stone back and forth until you get as deep as you want to go. Then move on to finer sandpaper 220, 400, 800. It's up to you how far you want to go making your window smoother. p.s. you do not need to wet the paper, but maybe wear a dust mask, and have fun. ht hermit Quote Link to post Share on other sites
dsvilko 12 Posted April 6, 2019 Author Share Posted April 6, 2019 Thanks for the suggestion but the thing is that I would very much like to double the number of stone fragments. I will be giving a small talk / presentation / workshop on the subject of cosmology, astrophysics and meteorites to a small group of school kids and would like to give each one meteorite fragment (without cutting I don't think I'll have enough for everybody and I would like to possibly keep a few interesting fragments for myself as I have just started collecting meteorites). I could possibly hit a few with a hammer and hope they break in decently sized chunks that I could then partly polish though I would very much prefer a more controlled demolition I do have some limited experience polishing meteorite slices with up to 1200 grit and can confirm that I was getting a much better results using a wet sandpaper (pure etanol, I was afraid to use water as it could encourage rusting). When I used a dry sandpaper the fine dust was somehow getting permanently stuck to the meteorite in some locations and couldn't be washed off, giving the surface a unnatural look. Any other ideas would be much appreciated. Quote Link to post Share on other sites
fredmason 1,135 Posted April 6, 2019 Share Posted April 6, 2019 A hack saw and maybe a vise will work...or you can cast them in some type of spackle, let it harden, then cut them....you can do it very low tech.... Chrondrites that I have cut are not very hard... fred Quote Link to post Share on other sites
Au Seeker 3,173 Posted April 6, 2019 Share Posted April 6, 2019 I would think you could cut them with a Dremel and a cutoff wheel, it would give you the best control IMHO. Quote Link to post Share on other sites
Nakhladog 12 Posted April 6, 2019 Share Posted April 6, 2019 https://www.amazon.com/gp/product/B00FPSWWT4?tag=s4343sdfd-20 I have used a similar Walmart saw, works great Quote Link to post Share on other sites
Morlock 1,722 Posted April 6, 2019 Share Posted April 6, 2019 52 minutes ago, Nakhladog said: https://www.amazon.com/gp/product/B00FPSWWT4?tag=s4343sdfd-20 I have used a similar Walmart saw, works great Guys, dsvilko is from Croatia so Walmart or any other big box retailer isn't feasible. I've had some success cracking geodes in half by chiseling all the way around ithe middle a few times, then breaking it open with one heavy blow. Perhaps you could use a hack saw blade to go around the middle of the stone a few times, then with a chisel..gently tap it and hope there's a clean break. 1 Quote Link to post Share on other sites
Strapped 216 Posted April 7, 2019 Share Posted April 7, 2019 Before I bought my rock saw I found a local jeweler who cut gem stones. He cut my meteorites for free. Quote Link to post Share on other sites
Bedrock Bob 4,057 Posted April 7, 2019 Share Posted April 7, 2019 You can get a diamond tile cutting wheel for the 4 1/2" angle grinder. I cut a big geode with one and it worked great. I clamped the stone between two boards and used a bug sprayer to keep water running through the cut. The cut was fairly flat and fairly smooth and didn't chip much. It certainly was not perfect but it worked out just fine for my purposes. And the agate was probably a lot harder than a chondrite. The little diamond blades are pretty common these days. You could rig up a mandrel for one and spin it with a drill motor. They will fit a small circular saw if you can set the foot low enough for the little blade to protrude. The diamond wheels won't cut your fingers so you can even hold tiny stones against the blade. Just be careful of the spraying water and the electric circuit. Cheap diamond wheels don't last long especially if you push hard on them. But for just a few specimens a cheap wheel will work fine. Even one that was thrown away from a tile job will go through most soft rock with a little patience. 1 Quote Link to post Share on other sites
wet/dry washer 197 Posted April 7, 2019 Share Posted April 7, 2019 wrap each with saran-wrap, line them up in a cardboard box and cover with plaster of paris. take to ceramic tile shop, tell him it's a school project, they will probably do it for free. then get some wet sand paper and let the kids polish them. do not sand dry. 1 Quote Link to post Share on other sites
dsvilko 12 Posted April 7, 2019 Author Share Posted April 7, 2019 Thank you all for excellent ideas! I will definitelly try some of them and report the results when my stones finally arrive. Quote Link to post Share on other sites
frank c 969 Posted April 7, 2019 Share Posted April 7, 2019 Get a bottle of non toxic RV antifreeze to use for "coolant" when cutting with a power tool. Quote Link to post Share on other sites
AzNuggetBob 1,553 Posted April 7, 2019 Share Posted April 7, 2019 Frank even using water for cutting coolant in fact any liquid coolant, any foreign substances could technically destroy the scientific integrity of the meteorite itself. IMO unless its a common well documented variety. the meteorite and its scientific value far out weighs the value of a cheap diamond saw blade. AzNuggetBob 1 Quote Link to post Share on other sites
Bedrock Bob 4,057 Posted April 7, 2019 Share Posted April 7, 2019 28 minutes ago, AzNuggetBob said: Frank even using water for cutting coolant in fact any liquid coolant, any foreign substances could technically destroy the scientific integrity of the meteorite itself. IMO unless its a common well documented variety. the meteorite and its scientific value far out weighs the value of a cheap diamond saw blade. AzNuggetBob Scientific integrity in this case is a specimen with a polished face to give to young students. Water or anti-freeze won't damage that because the value of the experience far outweighs any value that a little space rock has. Unless they are from a fresh fall or are a rare type most chondrites have very little scientific or monetary value. IMHO using them as a learning tool could only increase their worth. 1 Quote Link to post Share on other sites
fredmason 1,135 Posted April 7, 2019 Share Posted April 7, 2019 how can we complicate things...let me count the ways.... simple is always better and easier... fred 2 Quote Link to post Share on other sites
AzNuggetBob 1,553 Posted April 7, 2019 Share Posted April 7, 2019 1 hour ago, Bedrock Bob said: Scientific integrity in this case is a specimen with a polished face to give to young students. Water or anti-freeze won't damage that because the value of the experience far outweighs any value that a little space rock has. Unless they are from a fresh fall or are a rare type most chondrites have very little scientific or monetary value. IMHO using them as a learning tool could only increase their worth. Thanks for your two cents. AzNuggetBob 1 Quote Link to post Share on other sites
Bedrock Bob 4,057 Posted April 7, 2019 Share Posted April 7, 2019 20 minutes ago, AzNuggetBob said: Thanks for your two cents. AzNuggetBob And thank you for your seven cents worth! I think it was worth a dime. But I will have to owe you the nickel because I am broke. Quote Link to post Share on other sites
AzNuggetBob 1,553 Posted April 7, 2019 Share Posted April 7, 2019 8 minutes ago, Bedrock Bob said: And thank you for your seven cents worth! I think it was worth a dime. But I will have to owe you the nickel because I am broke. Wait a minute, you lost me in the math. AzNuggetBob 1 Quote Link to post Share on other sites
Au Seeker 3,173 Posted April 7, 2019 Share Posted April 7, 2019 20 minutes ago, AzNuggetBob said: Wait a minute, you lost me in the math. AzNuggetBob Bob, I think Bob was figuring his two cents into the equation. 2 Quote Link to post Share on other sites
fredmason 1,135 Posted April 7, 2019 Share Posted April 7, 2019 x plus y minus z equals.... 1 Quote Link to post Share on other sites
Bedrock Bob 4,057 Posted April 7, 2019 Share Posted April 7, 2019 (edited) 11 minutes ago, fredmason said: x plus y minus z equals.... ...A nickel. But I don't have it because I spend all of my time bow fishing and none of it working. And it does not look like things are going to change any time soon. Unless the fellows on this forum will accept cut bait as payment I am going to have to take their valuable opinions on credit. Edited April 7, 2019 by Bedrock Bob Carp. It's what catches dinner. 1 Quote Link to post Share on other sites
frank c 969 Posted April 7, 2019 Share Posted April 7, 2019 An I think you guys were using "CLINTON" math ! ========================================== Using a cooling agent will extend the life of your blade tremendously AND keep you from heating up BOTH the meteorite and the blade and don't breathe the dust from DRY CUTTING either. If you have something of tremendous rarity or value then BY ALL MEANS send it to someone in the know to fabricate, Otherwise if its a practice or playschool meteorite thing by all means use a wetting agent. 1 Quote Link to post Share on other sites
AzNuggetBob 1,553 Posted April 8, 2019 Share Posted April 8, 2019 frank your breathing meteorite dust every day whether you like it or not. AzNuggetBob 1 Quote Link to post Share on other sites
dsvilko 12 Posted April 8, 2019 Author Share Posted April 8, 2019 I do have an easy access to liquid nitrogen and even liquid helium. How's that for inert cooling? The stones are tiny and highly weathered so I don't think a bit of distilled water will make much of a difference. Not really expecting to discover new amino acids in a CI chondrite bought for $0.2/g. Quote Link to post Share on other sites
wet/dry washer 197 Posted April 8, 2019 Share Posted April 8, 2019 using water won't hurt, dry them with a hair dryer and shellac them, last for years. 1 Quote Link to post Share on other sites
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