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Post by newbiefromdibley on May 21, 2023 19:17:04 GMT -5
(I apologize if this has been addressed elsewhere but I couldn't find the info I need) I'm a newby and trying to understand the various products out there for tumbling and polishing. I'm confused about the relationship between grit vs mesh vs micron. In some sources (e.g. the fabulous Modern Rock Tumbling book by Steve Hart), as mesh size INCREASES, the micron size and the grit size both DECREASEe.g. he suggests trying the following silicon carbides in sequence as a starting point: 80-mesh (155 micron) 220-mesh (56 micron) 600-mesh (9.3 micron) 1000-mesh (4.5 micron) In other sources, like the following post, mesh size and micron size are very comparable across the range, and both DECREASE as grit value INCREASESforum.rocktumblinghobby.com/thread/94542/alternative-aluminum-oxide-powder-polishingHere, the mesh value only ranges from 0.5 to 160, but the GRIT value looks to be closer to the MESH values in the first source - CLOSE but not the same I'm confused when comparing advice and product information from various sources, as the parameters seem to contradict. Is there a standardized chart I should use? Thanks in advance
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Post by Starguy on May 21, 2023 23:11:42 GMT -5
Great question newbiefromdibleyMesh size refers to the number of openings per square inch in the sieve. Microns is the nominal particle size of grit In metric measurements.
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Post by newbiefromdibley on May 22, 2023 6:12:45 GMT -5
Thanks, but what I was querying is why the relationship between mesh size and micron size (and grit size) is different depending on which source you use. Logically, based on your definition it would make sense that as mesh size INCREASES (i.e. more holes per square inch) the micron size DECREASES (i.e. the smaller each one of those holes would be). But that's not what I typically see online e.g. www.gemsociety.org/article/gem-cutting-abrasives-grit-mesh-microns/Micron is obviously a definitive measurement, so is it possible that there are different meanings for the word 'mesh'?
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Post by Rockoonz on May 22, 2023 9:27:43 GMT -5
newbiefromdibley to my knowledge the writer of the IGS article is presenting some wrong information about mesh, in fact their entire article is riddled with inaccurate info, but most of it isn't going to change anything about how we process our rocks. 2nd take, the "mesh" numbers used for this article must be the metric version since they correspond with the microns, when I used screens in the rubber and plastics industry they corresponded with the US grit gauge, I believe the labels on the screen packaging may have included the metric measurement, but for my purposes I generally ignore that. The little differences between mesh and corresponding grit may be due to the shape of the particles, in other wirds something with gnarly structure may require a slightly larger screen mesh to allow essentially the same size particles through. For our purposes grit can be tightly graded of more of a range like gravel is x-minus. In tumbling we generally will use 60-90 ranged grit for coarse and 120-220 as the first 2 steps on a rotary tumbler, largely because the grit costs less. If using abrasive grit on a polishing lap or various types of sanding/polishing tools with diamond powder or paste a tightly graded grit is preferred since the action of the tool is a lot different than a slurry in a tumbler. Also in those applications we use a lot less, so the more expensive tightly graded abrasives are not a huge cost difference. For high precision applications like faceting even the directional orientation of the tiny diamond bits is important, which is why faceting laps cost so much more. In conclusion, when buying abrasive products for lapidary we are often buying things made by artisans for artisans, and my joke as more of a nuts and bolts guy is that artists need people like us to remind them that there are things like physics that they are bound to. What they say it does is often (always) more important than what they say it is.
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Tommy
Administrator
Member since January 2013
Posts: 12,646
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Post by Tommy on May 22, 2023 9:44:42 GMT -5
Welcome newbiefromdibley glad to have you here. FYI, I moved your thread out of the forum help area and into the Rock Tumbling area. Again welcome!
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Post by Starguy on May 22, 2023 11:25:02 GMT -5
Well put Lee RockoonzI was going to reply how it doesn’t matter that much as long as you’re in the range for what you’re trying to accomplish. It’s the motion of the tumblers which is doing the work. The grit is the tool designed for a specific result.
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Post by newbiefromdibley on May 23, 2023 6:59:55 GMT -5
Welcome newbiefromdibley glad to have you here. FYI, I moved your thread out of the forum help area and into the Rock Tumbling area. Again welcome! Thank you Tommy- sorry, still navigating my way around!
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Post by Mel on May 24, 2023 14:35:07 GMT -5
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Post by newbiefromdibley on Jun 4, 2023 19:02:37 GMT -5
Thanks for all your input. Let me turn this around then and ask 'what is a good polish to use for the final stage of rotary tumbling of mainly quartz, jasper and agate'? What grit/mesh/micron values should I be aiming for? I've read that cerium oxide is good for these, so can you recommend a specific product that won't cost a fortune in shipping? Would this be ok? www.amazon.com/gp/product/B074XC3QYG/ref=ox_sc_saved_image_1?smid=&psc=1
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Post by hummingbirdstones on Jun 4, 2023 22:47:20 GMT -5
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Post by newbiefromdibley on Jun 5, 2023 7:34:33 GMT -5
Thanks- yes that does seem to be a really popular choice, but the shipping costs for the size I would use are more than the cost of the product. I guess that's not an issue for big users but I was hoping to find something more reasonable for a light user like me.
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Post by southernlakehuronguy on Jun 5, 2023 7:57:45 GMT -5
Thanks- yes that does seem to be a really popular choice, but the shipping costs for the size I would use are more than the cost of the product. I guess that's not an issue for big users but I was hoping to find something more reasonable for a light user like me. I too like to save a buck when/where I can. I bought a 4 pound bag of Diatomaceous Earth from Tractor supply for my pre-polish for $13. I ran it for a week and was quite surprised at the shine I got. I E-mailed the manufacturer and asked what the micron size is, but never got an answer. But anyway, even though I haven't tried it, I would bet if one were to run it for 2 weeks, results would be great.I see Lowes sells a 7 ounce bottle for $8, and labels it as Organic Natural Insect Killer, but is D.E.
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Post by Rockoonz on Jun 5, 2023 9:49:29 GMT -5
Thanks- yes that does seem to be a really popular choice, but the shipping costs for the size I would use are more than the cost of the product. I guess that's not an issue for big users but I was hoping to find something more reasonable for a light user like me. I too like to save a buck when/where I can. I bought a 4 pound bag of Diatomaceous Earth from Tractor supply for my pre-polish for $13. I ran it for a week and was quite surprised at the shine I got. I E-mailed the manufacturer and asked what the micron size is, but never got an answer. But anyway, even though I haven't tried it, I would bet if one were to run it for 2 weeks, results would be great.I see Lowes sells a 7 ounce bottle for $8, and labels it as Organic Natural Insect Killer, but is D.E. Diatomaceous earth is not sold as an abrasive or polish to my knowledge, so asking for particle size is unlikely to get you an answer, but the Wiki indicates a wide range. Considering what it is I would think it will only work well with softer stones, since it is mostly fossilized algae. The good news is if you have problems with sand flies and their root eating larvau like we do the used slurry may be useful around young trees and plants.
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Post by southernlakehuronguy on Jun 5, 2023 13:35:07 GMT -5
Diatomaceous earth isn't advertised as an abrasive, but if you google it, it is used in many products as an abrasive, one in which is toothpaste.As far as effectiveness, here is something I copied...The effectiveness of diatomaceous earth is linked to how much silica it contains. Its particles have sharp edges that look like broken glass when examined under a microscope. These edges are able to cut through an insect's exoskeleton, and the powder sticks to its feet and skin. Once the powder is absorbed by the insect's body moisture, the insect dehydrates and dies.That is why I chose it as a pre-polish.Okay, I'll have to run a batch of mixed rocks through a 2 week polish cycle using D.E. just to see how it goes. I was just trying to help OP in finding something affordable.
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Post by newbiefromdibley on Jun 5, 2023 20:06:50 GMT -5
Thank you all for your suggestions, I'l give them a try
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