Re: [meteorite-list] Contamination during cutting - what impact does it have on analysis?
Hi Michael, I use the cutting rust preventative by Bill Mason that you Mix with distilled water (just a little goes a long way, making It very inexpensive). Bill is the developer/inventor of all the Paleobond products, but then got into meteorites. He knows His stuff. After slicing I put the slices in 96% alcohol (I can get it in Mexico). Regular "rubbing alcohol" is like 30% water - you want As little water as possible, as the alcohol soaks up the water, then Rapidly evaporates. I then set them on a paper towel on a plate which I put in the over to be super dried by the pilot light. Be sure They are very dry before removing. Otherwise, you will likely Be protected form rust due to the rest preventer, but your specimens Will weigh out heavy and then get "lighter" as they dry out. This time can be just a couple hrs for thin slices and 4 or 5 hrs For very thick slices - more for end slices thicker than 5 or 6mm. To get this cutting agent see BILL MASON near the Bottom of my home page: http://michaelbloodmeteorites.com For contact information. Best wishes, Michael On 5/18/10 11:44 AM, "Met. Michael Gilmer" wrote: > Hi List, > > I was wondering, while waiting for some freshly-sliced meteorites to > cool in the oven, what kind of contaminants does cutting add to the > meteorite? I am very careful and I only use distilled water as a > coolant - to prevent chlorine contamination of the specimens. But I > am sure that distilled water alters the specimens in some ways. Also, > I use a diamond-coated blade during cutting, so might this impart some > tiny diamond particles into the meteorite matrix? > > Let's assume an unclassified meteorite is sliced for classification - > if the analysis detects diamond, is it easy to discern if the diamond > was present prior to cutting or is it a contaminant from the cutting > blade? > > On a molecular level, I assume that stainless steel is shed from the > blade as well. Could this throw off elemental metal results? Besides > cutting, consumer polishing also imparts particles from the sandpaper, > buffing compound, rouge, or whatever else is used. > > I would imagine that NASA would use a sterile cutting tool and > environment, but most meteorite collectors and dealers don't. So what > exactly is in the prepared meteorite specimen you receive? > > Best regards, > > MikeG __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Contamination during cutting - what impact does it have on analysis?
Hi Mike, I just was reading last night about how they cut the Antarctic meteorites and they did a study on what is imparted to the meteorite from the blade (they don't use any coolants while cutting). Diamonds and some of the metal does smear and stick to the meteorite. Here's the link to the article (half way down the page). http://www-curator.jsc.nasa.gov/antmet/bandsaws.cfm The study also found traces of "organic" compounds that were contamination due to the plastic bags they used. Everything at some level is a contaminant, but I'd think certain obvious things are noticed and disregarded. NASA uses a nitrogen cabinet to store and cut their meteorites to prevent oxidation. Yes, they are more concerned about contamination due to the 'pristine' nature of their meteorites (no or little contamination from air pollution etc), but it still happens. I agree that water must do something to the chemistry, but not a clue what. -cheers, ryan __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Contamination during cutting - what impact does it have on analysis?
Hi List, I was wondering, while waiting for some freshly-sliced meteorites to cool in the oven, what kind of contaminants does cutting add to the meteorite? I am very careful and I only use distilled water as a coolant - to prevent chlorine contamination of the specimens. But I am sure that distilled water alters the specimens in some ways. Also, I use a diamond-coated blade during cutting, so might this impart some tiny diamond particles into the meteorite matrix? Let's assume an unclassified meteorite is sliced for classification - if the analysis detects diamond, is it easy to discern if the diamond was present prior to cutting or is it a contaminant from the cutting blade? On a molecular level, I assume that stainless steel is shed from the blade as well. Could this throw off elemental metal results? Besides cutting, consumer polishing also imparts particles from the sandpaper, buffing compound, rouge, or whatever else is used. I would imagine that NASA would use a sterile cutting tool and environment, but most meteorite collectors and dealers don't. So what exactly is in the prepared meteorite specimen you receive? Best regards, MikeG -- Mike Gilmer - Galactic Stone & Ironworks Meteorites http://www.galactic-stone.com http://www.facebook.com/galacticstone __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list