pacchardon
off to a rocking start
Member since August 2015
Posts: 22
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Post by pacchardon on Aug 9, 2015 15:57:45 GMT -5
I got my first tumbler for Christmas and for Father's Day got my second. Started with jaspers and agates using 60-90 grit for 3 weeks in stage 1. Would using some 46-70 cut down the amount of time for stage 1?
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 9, 2015 17:50:39 GMT -5
Absolutely! The lower grit will be much for efficient at grinding the harder stones (agates, and chalcedonies), and dramatically cut down your cycle times. Save your 60/90 for quartz to 6 in Moh's hardness. If spinning fast enough even with 23 grit, you could be adding grit every 3 days, and cut your grind times in half. 23-45 is ideal. Many other factors are equally important to consider: shape of barrel, barrel size, RPM..etc. The lower grit will work faster, also, which means increased wear on your liners.
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Post by glennz01 on Aug 9, 2015 23:34:18 GMT -5
sometimes cheaper also
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 16, 2015 11:24:33 GMT -5
Good point glennz. Coarser grits are cheaper. Since the finer the abrasive, the harder to separate. Unfortunately, many re-sellers seem to keep the coarser grits at the same price as the 60/90 to make more money.
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Post by glennz01 on Aug 17, 2015 23:10:28 GMT -5
Good point glennz. Coarser grits are cheaper. Since the finer the abrasive, the harder to separate. Unfortunately, many re-sellers seem to keep the coarser grits at the same price as the 60/90 to make more money. That is true but some places sell it really cheap... whenever I need course grit I will buy 50 lbs from here along with more diamond dremel bits... Shipping costs a bit so I usually try to order a lot of stuff and for other people. link
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 18, 2015 12:14:05 GMT -5
thanks for the tip glennz. Good to know. Keep in mind that there is a huge quality range of grit. ROCK hobby retailers are just small consumers of grit, and remarket everything.
Most of the grit today comes from China, and there are huge quality swings. So, when a reseller has a "deal", be on guard. It is usually because they are looking for better sources, and got a lower quality material at a cheaper price. I studied Rockshed's grits, and confirm they are top quality at reasonable prices. I have not looked at any other sellers, and not trying to promote anyone either. I buy a lot of grit for our factory directly from a Chinese manufacturer. I rely on 1 and have 3 in backup. I used to focus on price: $.60/kg per ton for 60 grit. There is even $.30/kg per ton material that is horrible. Looking under the microscope, you can see that the more expensive materials are better quality. I can send anyone images that interested in seeing. Low grade looks like good quality mixed with "50% popcorn filler". High quality is green crystals.
There is nothing wrong with lower grade grits, you just tend you use more. The bad needs even 4x more. So when 50% off, i bet if we look carefully there is a reason..
Also polish - many resellers remarket commonly known abrasives as "magic polish 101" or even use there on name. The hope is you will have success with it, and then rely on buying their "exclusive" branded polish. There is no secret (it is either <2 microns or < .5 micron AL Ox. depending on the goal) So, when they do not offer you a data sheet on the abrasive, you shouldn't buy it...(by law the size of the abrasive must be disclosed in trade, if requested).
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,563
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Post by jamesp on Aug 18, 2015 12:20:58 GMT -5
"So, when they do not offer you a data sheet on the abrasive, you shouldn't buy it...(by law the size of the abrasive must be disclosed in trade, if requested)." Read more: forum.rocktumblinghobby.com/thread/71762/60-coarse-grit-extra-course?page=1#ixzz3jBjLSOFUOh yes, so true. Not sure that a range of sizes makes that much difference with finer AO grades for tumbling within reason. The most expensive AO is finer grits truly sized to one size. Precision screening is expensive. Screen the small grits out of the target. Screen the target out of the bigger grits. Lots of work. AO in a range is way cheaper. And a range works fine for most tumbling applications since the target is to beat it down to a smaller grit size. I called some suppliers and was surprised at the range in 'pre polish' and 'polish'. And the range being sold as 500-1000-5000 etc. Look up single range AO 5000 for instance. Expensive. It is still allowed a range because of mechanical limitations in screening something so small. Smaller the range the more the cost. If you need a 5000 finish on a highly stressed helicopter rotor due to scratches from 3000 particles propagating fractures; there best not be any 3000 particles present. Dealing with human lives in such a situation. I am certain that the AO 500-1000 and 14,000 from the Rock Shed does a darn good job. And I would guess each of them has a range, but seems to have no negative effects when tumbling with them. Point proven if you can put Rock Shed AO 500 in a vibe with agate and get a darn nice polish after 1-4 days. C'est la vie. SiC sure does have levels have quality. It can be cut with lesser quality material, usually flat pieces of SiC. The best shape for SiC particles is closer to round than flat for superior grind performance.
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 18, 2015 12:50:46 GMT -5
Of course not. I wouldn't. I need to know what I'm working with. RS doesn't disclose. I asked, and I was told. I'm fine with that.
This is really targeting the polish. "What is it? I dont know but it works..." If it is a household cleaning product, they can get away with that. If they are selling an abrasive, from what I know, they must disclose. There is nothing for them to fear, since it is really the QUALITY of the product, and its purity that should be the "secret". What's with the need of almost every rock shop to claim to have a secret sauce?
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,563
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Post by jamesp on Aug 18, 2015 13:13:29 GMT -5
Of course not. I wouldn't. I need to know what I'm working with. RS doesn't disclose. I asked, and I was told. I'm fine with that. This is really targeting the polish. "What is it? I dont know but it works..." If it is a household cleaning product, they can get away with that. If they are selling an abrasive, from what I know, they must disclose. There is nothing for them to fear, since it is really the QUALITY of the product, and its purity that should be the "secret". What's with the need of almost every rock shop to claim to have a secret sauce? Abrasive companies often take a deep breath when asked about the size range of their product. They are about all described on a bell curve and the math can be complicated. And the range is usually bigger than the customer was expecting. They are quick to send samples to 'try' for your given process. Glad I found good abrasives that work.
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Post by glennz01 on Aug 18, 2015 13:20:18 GMT -5
I would be interested in seeing other pages that offer good quality grit for cheap.
The polish I got came from black cat mining and works like all the other polishes I used. I should ask for the size but... for finishing the final polish on my cabs I use this stuff and it puts a glass shine on agates not using much polish.
They have the cheapest polish that I could find and were willing to take it out of the tub and put it in bags to lower the cost of shipping. I will get more polish from them most likely unless my local lapidary shop guy can give me a better deal. .since i'm more than a customer maybe he can give me close to what he paid from kingsley north, presuming thats where he gets it from.
Please do post links and a microscope image would be interesting to see of the 60/60 grit or whatever type)
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 18, 2015 17:27:19 GMT -5
good quality Black SiC 60/90 from a reputable company 16x 60x below
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 18, 2015 18:05:29 GMT -5
Of course not. I wouldn't. I need to know what I'm working with. RS doesn't disclose. I asked, and I was told. I'm fine with that. This is really targeting the polish. "What is it? I dont know but it works..." If it is a household cleaning product, they can get away with that. If they are selling an abrasive, from what I know, they must disclose. There is nothing for them to fear, since it is really the QUALITY of the product, and its purity that should be the "secret". What's with the need of almost every rock shop to claim to have a secret sauce? Abrasive companies often take a deep breath when asked about the size range of their product. They are about all described on a bell curve and the math can be complicated. And the range is usually bigger than the customer was expecting. They are quick to send samples to 'try' for your given process. Glad I found good abrasives that work. jamesp-your right. Many play the hold the breath game, but many do not, once they know you are a real customer and not a threat to their "secrets". They buy a specific grade and they should disclose the abrasive size (fixed or the range) they are selling, so you know what it is... Nothing wrong with Jamesp-secret sauce-101. But if you call them up, the seller should say "its <1 micron Al Oxide". This just states the mesh size and the abrasive. and this information should justify the price when dealing with, for example .3 micron should be the most expensive. So the person learning, understands the process, and not caught up in false and confusing marketing. Keep in mind that you are far more advanced than anyone here, so you actually think about the options when you polish. Most just polish....and that's plenty fine. Ideally the package would simply specify what it is we are using. Don't get me wrong, because the these lapidary resellers are needed - its just the games many play to hide the information, in order to profit. In a sense, misinformation. How to learn about the true hobby without toying around...? The more options the better. I would buy only from the sellers that help me learn, support me, in order to win my repeat business.
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Post by glennz01 on Aug 18, 2015 18:48:15 GMT -5
stonemaster499What does bad grit look like? I have a 30x magnifier (which I can get higher) to compare. Thanks
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stonemaster499
noticing nice landscape pebbles
Member since July 2014
Posts: 97
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Post by stonemaster499 on Aug 18, 2015 19:37:30 GMT -5
lower quality SiC. You can see by the color, crystal structure, and purity. Green is the top quality. The sample I showed was from black 60/90 SiC seller popular in these forums. Good quality for black SiC 60/90 and sizing is correct. Better quality is more green and translucent. Lower quality you see more mixture of sizes, opaque, fillers (looks like popped popcorn). The lower quality was seen by my staff, and they dont have access to a 220x microscope, and saw what i described using a 10x loupe.
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Post by glennz01 on Aug 18, 2015 19:46:25 GMT -5
i'll have to take a look and see how good it is
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jamesp
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Member since October 2012
Posts: 36,563
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Post by jamesp on Aug 18, 2015 19:55:47 GMT -5
Ha, I have no idea what works best except by trail/error stonemaster499. After studying the various aluminum oxides I was perplexed, much less the size distribution. The coarse SiC was straightforward. Good quality 30/60 and 45/70 SiC is great for coarse grind. If I had my druthers I would use high grade straight SiC 30.
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