kuullandor
off to a rocking start
Member since February 2018
Posts: 3
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Post by kuullandor on Feb 24, 2018 18:08:40 GMT -5
Hi everyone! I've been collecting stones since I was a kid. I received my first stone from my grandmother when I was 12 and it was a polished amethyst. It has been my most treasured piece in my collection of rough and polished gemstones. The deep, dark purples grabbed me immediately. I always thought about tumbling stones, but I didn't really get started until this past Christmas, when I received a new tumbler from my parents as a gift. After having only tumbled what came in the box with the tumbler and failing the first time, I decided to be a little more scientific about this. I tumbled my first rough following the instructions which came with the tumbler, assuming the instructions were correct. It is a NatGeo tumber, 1lbs capacity. They need to be put back in to polish or possibly pre-polish them again. I was a chemistry and physics double major with a minor in mathematics in college (but I never finished). Having said that, I decided to throw together a spreadsheet (which I will attach), but I want specifics for the calculations. What I'm looking for is a balance scale that calculates to the thousandths place in grams. I have already ordered weigh boats and spatulas for it, but I can't seem to find anything on Amazon that fits my needs. I'm looking for something that will support upwards of two to three kilograms, that way I can determine the total mass in my barrel (including any ceramic media I may need) and get more accurate data for my chart. I'm looking for a balance that is inexpensive ($20 - $40 range). I decided (against all other advice ) to tumble 1 lbs of sapphire. I don't know the exact mass because I don't have a scale and that's what I need. I'm just assuming 2.27 kg (I ordered one pound off of Amazon, so I'm playing fast and loose). Any assistance would be helpful. Additionally, how long should I be tumbling sapphire with silicon carbide for my coarse grit? Tumbling Diary.xlsx (11.63 KB)
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Post by aDave on Feb 24, 2018 18:58:33 GMT -5
Welcome to the forum. Interesting project you have there. Just a couple of questions, if you don't mind.
I'm curious why you are going to weigh out all of your material. Most recipes and tumbling instructions deal more with volume in the barrel instead of weight. Had you found something that lists otherwise?
You asked about how long you should be tumbling sapphire in coarse with silicon carbide grit. Since both are the same hardness on the Mohs scale, you'd probably be in for an uphill battle with little to no results...at all. You are going to need grits that are harder than the target material in order to have any effect on the stones. Since such grit would be out of the norm, I'd have to expect it would also be pretty expensive.
If you're just starting out, I'd be recommending a totally different route in terms material to start with. Then again, I think you know that based upon your comment above. Best of luck.
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Post by vegasjames on Feb 24, 2018 19:31:42 GMT -5
Welcome to RTH.
Scales have come way down in price. You can get really accurate ones pretty cheap anymore on Amazon or Ebay. Just add the specs of 0.1 or 0.01 etc that you want for accuracy.
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Post by Jugglerguy on Feb 24, 2018 19:52:48 GMT -5
Welcome to the site. There have been several new people here lately who have been frustrated by that tumbler. The directions that come with it are definitely misleading, as well as possibly the polish and rocks that come with the tumbler. Here’s a link to a recent thread from someone asking for help. Apparently he didn’t like our advice because he deleted his account. I thought we had some good ideas to try. I believe rockcat11 has had some luck with the National Geographic tumbler.
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rockcat11
starting to spend too much on rocks
Member since August 2017
Posts: 176
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Post by rockcat11 on Feb 24, 2018 22:31:25 GMT -5
I have had some success with the nat geo tumbler. My best advice: Throw out the directions. Get different grit, the stuff that it comes with is garbage. I do the first tumble for anywhere from 1-6 weeks depending on what I am tumbling, with recharges as needed. Steps 2-4 I do for a week each. I use plastic pellets as tumbling media in the pre-polish and polish stages, with about a 60% media to 40% rough ratio. I also clean the living daylights out of the barrel and the rocks before I move them on. Be picky about what you tumble. Anything with pits or big fractures will trap pieces of grit and it will impact the quality of the polish. I am still learning myself. Above all else: be patient. Here is an example of some of the stuff that I have gotten out of my tumbler.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,685
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Post by Fossilman on Feb 27, 2018 15:37:42 GMT -5
Welcome to the forum.....
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kuullandor
off to a rocking start
Member since February 2018
Posts: 3
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Post by kuullandor on Feb 27, 2018 20:51:58 GMT -5
Hi all! Thanks for your feedback and help. I REALLY appreciate it. So, the reason I wanted to list the value of mass is specifically because I'm a nerd and I like to be thorough. Since I know it is a one pound barrel, I can better keep track of the total mass (rough + tumbling media) inside. Incidentally, thank you for answering a not thought of question: What is the hardness of SiC? All I had read is that SiC is one of the hardest minerals known to man. I figured it would have been harder than corundum. So thank you for that info, aDave! Very helpful Incidentally, no I haven't found anything that says otherwise, I just thought it might be a metric worth recording. Knowing the accurate and precise mass and density will tell me the volume of material in the barrel. I was looking at the scales available on Amazon, but I was looking for something inexpensive that can measure the mass up to 5 lbs. It was late when I was looking and I couldn't find anything, so I'll look again. Fingers crossed. Thank you, vegasjames, I'll look harder. I did want something to measure to 0.001g, but if I can't find a scale measuring that far out, I'll have to settle. Jugglerguy and rockcat11: I have to agree with you, the instructions that came with the tumbler are garbage. I did a little research on what was being tumbled in the "beginner" mix which came with the tumbler. I just assumed the rough would be of a similar hardness for each stone. After a quick search, I found out that the hardness of the various stones went to as low as 3 on the Mohs and up to 6-7. I immediately knew why they weren't pretty.... I was too excited to start so I didn't do any real research beforehand. Shame on me. In the link shared by Jugglerguy (thank you for the link, btw), I see that small plastic pellets were recommended in the barrel. My mother shared an article with me on RockTumbler.com suggesting the use of ceramic filler media, as the plastic pellets were too difficult to clean properly. I purchased one pound of those to use as filler. What would your suggestions be, based on your experience? Ceramic (large and small) versus plastic pellets? I am nearing one week into tumbling the sapphire, I know it will be difficult. I read (before I started tumbling them) that I should use either B4C or diamond. I thought maybe I could get away with the SiC. Guess not! Based on everyone's feedback, I may (read: am going to) switch to something easier to tumble and go back to the sapphire (and sadly emeralds) at a later date. I'll do those once I get comfortable with the NG tumbler and switch to a different and larger tumbler like one of the Lortones. I am going to pull them out and wash them on Friday (03/02/2018) and see how they look compared to how they looked when I got them. If not much has changed, I will definitely switch to something else. Also, any better suggestions for cleaning the tumbler? Currently, I'm alternating with an extra firm toothbrush (to scrub manually) and then tumbling warm water and Ivory soap shavings (for 2-3 hours). Could anyone suggest anything better? I just don't feel like a toothbrush does a good enough job, but that's just me. I will switch to Borax to clean between batches; I read on (I believe) RockTumbler.com you could use either Ivory soap or Borax. In the link to the thread provided by Jugglerguy, Borax was recommended (thank you again for the link). To everyone, thanks for your replies! You all helped me a lot.
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Post by Jugglerguy on Feb 27, 2018 21:14:35 GMT -5
kuullandor, I do all of my stages after the first in a Lot-O vibratory tumbler. In a vibe, there is no choice between ceramic and plastic. I have finished a few batches in a rotary tumbler and I have used plastic there. Some people swear by plastic in a rotary, some use ceramic in a rotary, some mix the two or use one for one stage and another for other stages. I think it's safe to say that both can work. Plastic has to be changed with each stage. It cannot move along with the stones because grit gets imbedded in it. So the plastic you use in the 500 stage gets saved for the next 500 stage. When you move to polish, use plastic dedicated to the polish stage. Ceramic on the other hand is hard and grit does not get imbedded in it. It's fine to move the ceramic from stage to stage with the rocks. As for cleaning the barrel, just run the rocks for a couple hours with ivory soap or borax and then rinse everything again. Do this twice between stages to be extra careful. You don't need to scrub with a toothbrush, just rinse it out several times. It's nice to have a separate barrel just for polishing.
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Post by TheRock on Mar 1, 2018 13:36:15 GMT -5
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