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Post by bobby1 on Oct 6, 2016 13:41:08 GMT -5
I have some tumbling grits labeled 3F and 4f. How do these designations relate to the 220, 400 and 600 grit designations? Bob
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Post by Drummond Island Rocks on Oct 6, 2016 14:41:37 GMT -5
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Post by bobby1 on Oct 6, 2016 15:46:43 GMT -5
Thank you for the chart but I can't see any reference to 3F or 4f. Is there something that I'm missing? Bob
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Post by Drummond Island Rocks on Oct 6, 2016 16:07:09 GMT -5
Thank you for the chart but I can't see any reference to 3F or 4f. Is there something that I'm missing? Bob The bottom chart has FFF (16 microns) and FFFF (11 microns). I guess I was assuming that is 3F and 4F?
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Post by orrum on Oct 6, 2016 18:13:39 GMT -5
I researched that one time. The info I found indicated that the F designations were not silicon carbide or AO grits but we're Pumice grit sizes. At one time pumice was a thing. I could of bought a boatload cheap.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on Oct 7, 2016 0:18:00 GMT -5
Quote from "Gem Tumbling and Baroque Jewelry Making" by the Victors, 25th edition, 1984, pg. 15: "The "F" grades are first class material but the classification of particle size is not as exact as the numbered grades. 2F for instance would be number 280 or finer. It might contain a few grains larger than 280-3F would be 320 and finer. We believe these F grades are excellent for tumbling because of the finer material-but it would not be suitable for lapping. The price is much lower than corresponding number grades."
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Oct 10, 2016 13:41:29 GMT -5
Sorry to jump in. Grit Systems are different outside the US. The US uses the ANSI system, which is what we are used to. Europe, and the rest of the world uses FEPA. These systems are different, but similar - and nothing to do with the abrasive (ie SiC or Al.Ox) F1000 (FEPA) = 4.5 microns, whereas 1000 grit (ANSI) = 5.8 microns. so you can see there is some difference in the sub-micron sizes, but basically interchangeable in larger sizes. F100 = 125 micros, and ANSI 100 grit = 125 microns I hope this helps clear up some confusion.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Oct 10, 2016 15:24:47 GMT -5
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Daimon
off to a rocking start
Member since January 2018
Posts: 20
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Post by Daimon on Feb 7, 2018 17:21:35 GMT -5
Being new to this I am still getting my head around what I need.
I bought a kit from National Geographic which came with grits labelled as Stage 1, 2, 3 and 4.
Thanks to this site I am starting to understand the process and needed to order grit. I found one supplier who told me I only needed grit grades of 80, 400, and cerium oxide polish. This confused me a bit because most articles speak of a 4 stage process. I also asked about plastic pellets and I was told they are really only for professional use. I am not doing this for money but I still want good results. However, I purchased what he said for now. But, the more I read on the forum the less happy I am with the advice from that supplier.
I have found another supplier in the U.K. who supplies Silicon Carbide grit in the following grades.
24. 60. 180. 320. 400. 800 and 1200: They also supply cerium oxide. However, these don't seem to fit in with the 80-220-400-polish.
Which grades of grit should I buy to get the best results and does anyone recommend plastic pellets?
Thanks. Daimon
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