rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 86
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Post by rockrockrock on Feb 27, 2021 21:43:11 GMT -5
Hello, Everyone. I'm not a rockhound, but I've gotten great advice from this forum in the past. I make a consumer product out of different kinds of expensive plastics. One of my matierals does not like water, so I polish it dry. Over the past two years I've had a lot of success putting a little Aluminum Oxide powder (dry, no water) on a smooth pad or even a dry chamois and just doing it that way, by hand. The results are amazing. Because the material I use is like a gemstone it shows the very tiniest micro-scratches, so even after this application there's still some work to do. After the chamois thing, I put the workpiece into a vibratory tumbler and run it dry in corncob with successive grit ratings of 14,000, then 25,000, then 50,000, and finally 100,000. After that, I finish it off with a cotton buff and jewelry rouge. It really comes out gorgeous. The link below is to the kind of powder I've been using, known as Linde A, which works great but is very expensive. I believe there is a less expensive alternative out there that will do what I need to do, but I'm quite clueless in this area. Would love your suggestions, and if you have direct links all the better. cuttingedgesupply.store/products/linde-a-polish?currency=USD&variant=33348647944291&gclid=Cj0KCQiA-OeBBhDiARIsADyBcE6r2Qyr8-bnrK2aRjupF62lSWzTdRC1ZJbkW6ks9pAwNjbqflPg1PAaAqLvEALw_wcBOne more bit of information. The stuff above has an abrasive particle size of about .3 micron, which translates to about a 75,000 grit rating. I don't anything nearly that fine. Anything in the range of a 1-2 micron abrasive particle (10,000-15,000 grit rating) would probably work great AND save me a lot of money. The vibe tumbling will take over from there, and it works gangbusters. Thank You in Advance for your expertise and insights, RRR
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 28, 2021 4:43:42 GMT -5
Rock Shed alum ox polish is 14,000 grit/1 micron and does a fine job. Not sure about the size distribution but it seems quite pure. Be aware that average priced aluminum oxide abrasive is allowed to have a lot of particle size variation. When a tumbler is tumbling hard rocks the aluminum oxide breaks down to much smaller sizes. Not so when tumbling soft plastic unless running hard media with it like polishing ceramics. On subject of particle size variation for our aluminum oxide tumbling abrasives: This is Comco advertising their alum ox 285 grit/55 micron has a tighter size bandwidth than 'others'. But it has a lot of AO 220 to AO 600 mixed in with it. This variation is legally allowed to be advertised as AO 285 !! What you see advertised is rarely what you get. Pure AO 285 would cost many times more. Pure AO 400 +/- 5% probably costs $40/ounce. And super fine Linde a alum ox is expensive anyway. .3 microns is incredibly small to easily manufacture and sift to pure into 100% .3 microns. Particles size bell curve: Grit to micron conversion
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Post by As I in does tries! on Feb 28, 2021 4:43:46 GMT -5
Greetings and welcome from Scotland, yes Union Carbide's Linde-A (Aluminum Oxide) is very expensive it was usually sold by the ounce, as it is aimed at faceters, however there are plenty no-name Aluminum Oxide can be bought for as little $4 per pound, then there are other compounds such as medical grade Borax (Borax Ph. Eur), medical grade Titanium Dioxide and Zinc Oxide see my tumbling guide in my signature. Zinc Oxide is available from UKGE see Lapidary Vendors Worldwide.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 28, 2021 5:10:49 GMT -5
Greetings and welcome from Scotland, yes Union Carbide's Linde-A (Aluminum Oxide) is very expensive it was usually sold by the ounce, as it is aimed at faceters, however there are plenty no-name Aluminum Oxide can be bought for as little $4 per pound, then there are other compounds such as medical grade Borax (Borax Ph. Eur), medical grade Titanium Dioxide and Zinc Oxide see my tumbling guide in my signature. Zinc Oxide is available from UKGE see Lapidary Vendors Worldwide. Tell it As I in does tries!. About all of the alum ox purchased for rock tumbling is cheap grade AO. Think what you want but it's a fact. No matter since it breaks down(actually it rounds to smooth)..
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 86
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Post by rockrockrock on Feb 28, 2021 13:41:19 GMT -5
Greetings and welcome from Scotland, yes Union Carbide's Linde-A (Aluminum Oxide) is very expensive it was usually sold by the ounce, as it is aimed at faceters, however there are plenty no-name Aluminum Oxide can be bought for as little $4 per pound, then there are other compounds such as medical grade Borax (Borax Ph. Eur), medical grade Titanium Dioxide and Zinc Oxide see my tumbling guide in my signature. Zinc Oxide is available from UKGE see Lapidary Vendors Worldwide. Tell it As I in does tries! . About all of the alum ox purchased for rock tumbling is cheap grade AO. Think what you want but it's a fact. No matter since it breaks down(actually it rounds to smooth).. James, thanks to you and the other posters. Since I am totally foreign to this world, could you possibly recommend a couple websites who sell this stuff, and/or even post some links. Also, in general, I just really resent paying shipping. If it's available on Amazon or eBay or somewhere else with no extra freight charge this is where I want to buy. It just really rankles me. We sell a consumer product through our site and we NEVER charge for shipping. This was the #1 consideration I had when forming the company. Thanks again for any further info. RRR
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 86
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Post by rockrockrock on Feb 28, 2021 13:47:03 GMT -5
Greetings and welcome from Scotland, yes Union Carbide's Linde-A (Aluminum Oxide) is very expensive it was usually sold by the ounce, as it is aimed at faceters, however there are plenty no-name Aluminum Oxide can be bought for as little $4 per pound, then there are other compounds such as medical grade Borax (Borax Ph. Eur), medical grade Titanium Dioxide and Zinc Oxide see my tumbling guide in my signature. Zinc Oxide is available from UKGE see Lapidary Vendors Worldwide. Tell it As I in does tries! . About all of the alum ox purchased for rock tumbling is cheap grade AO. Think what you want but it's a fact. No matter since it breaks down(actually it rounds to smooth).. Actually, I found it and this is VERY reasonable and sounds perfect. Could you please just confirm that this is the correct item, before I place my order? www.rockshed.com/rock-shop/rock-tumblers-supplies/rock-tumbling-grit-and-accessories/aluminum-oxide-polish/Thank You, RRR
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Post by rmf on Feb 28, 2021 14:40:46 GMT -5
Cerium-R Oxide 1.2 MICRON SIZE
Linde 'A' Polish A .3 micron alumina powder that is 99.98% pure aluminum oxide polishing powder with a 9 mohs hardness. A super polish for almost any gemstone.
Mirco Aluminum: Covington's Gold Label Polish #1 99% pure micro alumina polishing powder. Excellent for vibrating tumblers, lappers, and ultrasonic machines. Great for Petrified woods, Agate, Rhodocrosite, Jade and other stones. Approximate size 2 - 3 microns and a 9 on the MOHS scale.
Covington's Gold Label Polish #2 99% pure micro alumina polishing powder. Excellent for vibrating tumblers, lappers, and ultrasonic machines. Works especially well with Leather or Felt. Great for super fine polish on all hard and soft stones. Approximate size .5 microns and a 9 on the MOHS scale.
Tin Oxide 99.9% Ultra High purity tin oxide. Over 85% particle size distribution 1 micron or less, and 58% is .37 micron. Excellent polishing on almost any gemstone including hard to polish stones.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 28, 2021 17:21:08 GMT -5
The Rock Shed link is correct. That would be my suggestion.
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 86
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Post by rockrockrock on Feb 28, 2021 17:36:48 GMT -5
The Rock Shed link is correct. That would be my suggestion. James, thanks for all your help on this. It looks good. There appear to be very few specs on this item on their site, so I've written them to verify the grit and mesh ratings before placing my order. However, anything around 10,000 or higher should work fab for my application. Starting at 14,000 (or sometimes even 8000), I switch to corncob vibe tumbling which does a terrific job. Thanks Again, RRR
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Feb 28, 2021 18:55:47 GMT -5
The Rock Shed link is correct. That would be my suggestion. James, thanks for all your help on this. It looks good. There appear to be very few specs on this item on their site, so I've written them to verify the grit and mesh ratings before placing my order. However, anything around 10,000 or higher should work fab for my application. Starting at 14,000 (or sometimes even 8000), I switch to corncob vibe tumbling which does a terrific job. Thanks Again, RRR Good luck RRR.
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Post by Bob on Mar 1, 2021 16:05:32 GMT -5
I don't do any kind of high end polishing, but do have a retired client that did, although he can't tell me too specifically about what he did and why because some of it is classified. But one day he tried to tell me what really happens on a microscopic level when a polish polishes the target material, which is usually harder than the polish. He spent 3 years comparing super fine diamond dust vs. high grade cerium oxide for some applications. He lost me in the science because it got too complicated. He really lost me when he said the amorphous surface of the target material when successful for some materials has some things in common with a liquid! But one thing I do remember is the number of variables are intimidating (spectrum of dry to wet, what carrying agent liquid, material of polish pad, purity of polish, uniformity of polish particles, pressure, ambient temp, heat at interface, whether polishing room has filtered air and if so what level, frequency of cycles, and many more). He definitely said that everyone thinks the finer the polish (least micron size particles) must be a better polish, but this isn't true.
Posted just in case any of that is helpful because I have no direct knowledge of this topic.
He also told me that some polishes in rock tumbling may get better with repeated uses. I have never yet thrown away a polish, and some is now 5 years old but I've never kept rocks polished years ago from those recently polished to see if shine looks any different or the same.
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rockrockrock
noticing nice landscape pebbles
Member since August 2016
Posts: 86
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Post by rockrockrock on Mar 1, 2021 19:53:44 GMT -5
I don't do any kind of high end polishing, but do have a retired client that did, although he can't tell me too specifically about what he did and why because some of it is classified. But one day he tried to tell me what really happens on a microscopic level when a polish polishes the target material, which is usually harder than the polish. He spent 3 years comparing super fine diamond dust vs. high grade cerium oxide for some applications. He lost me in the science because it got too complicated. He really lost me when he said the amorphous surface of the target material when successful for some materials has some things in common with a liquid! But one thing I do remember is the number of variables are intimidating (spectrum of dry to wet, what carrying agent liquid, material of polish pad, purity of polish, uniformity of polish particles, pressure, ambient temp, heat at interface, whether polishing room has filtered air and if so what level, frequency of cycles, and many more). He definitely said that everyone thinks the finer the polish (least micron size particles) must be a better polish, but this isn't true. Posted just in case any of that is helpful because I have no direct knowledge of this topic. He also told me that some polishes in rock tumbling may get better with repeated uses. I have never yet thrown away a polish, and some is now 5 years old but I've never kept rocks polished years ago from those recently polished to see if shine looks any different or the same. Bob, interesting stuff. Thanks for your input. I continue to always experiment, although I have a process working for almost two years now that gives me the results I need. I think the Rock Shed material mentioned above my another method would get me where I need, and it's dirt cheap compared to the other stuff I've been using. I'm gonna give it a try and play with it a bit. Lots of trial and error, but I love learning new things every day -- especially if a new process saves us $$$ -- so I'll definitely give it a whirl. Thanks, Bob. RRR
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