alecogeorgia
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Antithesis of tumbling - Friction retards progress
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Post by alecogeorgia on Apr 1, 2017 6:50:17 GMT -5
Hello tumbling wizards! Have you ever tumbled tanzanite small chips? It is amazing, that I cannot find any information in the web. Such popular stone.. I would like to try for my wife's mosaics. Interesting challenge! I will start with Si 120/200, then AO 500, 1000, polish. What do you think?
Thank you Alec
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jamesp
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Post by jamesp on Apr 1, 2017 9:17:43 GMT -5
Your recipe looks great. I would use the small tanzanites as 40-50% filler and run 50-60% agates about 1 to 1.5 inches in size. The mix of sizes is more important than the recipe in sorts, tumbling a batch of only tiny pieces takes forever.
Welcome from Georgia.
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alecogeorgia
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Antithesis of tumbling - Friction retards progress
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Post by alecogeorgia on Apr 1, 2017 15:24:13 GMT -5
Thank you Jamesp. I thought to use plastic pellets to smooth tumbling and save tanzanite. Why do you think hard stone like agate is better choice?
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jamesp
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Post by jamesp on Apr 2, 2017 11:36:37 GMT -5
Thank you Jamesp. I thought to use plastic pellets to smooth tumbling and save tanzanite. Why do you think hard stone like agate is better choice? I tried tumbling a buch of 1/4 inch glass and 3/16 inch garnets by themselves and they never would round off smooth. Need a mix of sizes !! Small stuff needs big stuff to create grinding pressure. It is for mechanical reasons. Even the barrel full of small soft glass at Mohs 5 would not round off. Tanzanite at Mohs 6.5 will be yet more stubborn. It is a stone that is faceted, quite durable. I learned this big rock thing accidentally by running a 1 pound rock with a bunch of normal sized agate tumbles. The big rock speeds up the grind rate plain and simple on tough agates. Don't use a 1 pound rock, may/will damage your delicate chips. Just add 50% agates 1 to 1.5 inches in size. Plastic pellets just retards grind IMO. Yes it protects, but you can add target rocks like small agates and tanzanite chips till barrel is 80% full with 50/50 chips and 1.5" agates and you will have a very gentle tumble. "A mix of sizes" is sort of a golden rule for efficient tumbling. I put 20% 3/16" garnets in with regular tumbles and they round well. They are hard almandines at about Mohs 8. Very stubborn.
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alecogeorgia
off to a rocking start
Antithesis of tumbling - Friction retards progress
Member since January 2016
Posts: 16
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Post by alecogeorgia on Apr 4, 2017 20:28:54 GMT -5
Thank you Jamesp. I thought to use plastic pellets to smooth tumbling and save tanzanite. Why do you think hard stone like agate is better choice? I tried tumbling a buch of 1/4 inch glass and 3/16 inch garnets by themselves and they never would round off smooth. Need a mix of sizes !! Small stuff needs big stuff to create grinding pressure. It is for mechanical reasons. Even the barrel full of small soft glass at Mohs 5 would not round off. Tanzanite at Mohs 6.5 will be yet more stubborn. It is a stone that is faceted, quite durable. I learned this big rock thing accidentally by running a 1 pound rock with a bunch of normal sized agate tumbles. The big rock speeds up the grind rate plain and simple on tough agates. Don't use a 1 pound rock, may/will damage your delicate chips. Just add 50% agates 1 to 1.5 inches in size. Plastic pellets just retards grind IMO. Yes it protects, but you can add target rocks like small agates and tanzanite chips till barrel is 80% full with 50/50 chips and 1.5" agates and you will have a very gentle tumble. "A mix of sizes" is sort of a golden rule for efficient tumbling. I put 20% 3/16" garnets in with regular tumbles and they round well. They are hard almandines at about Mohs 8. Very stubborn. Thank you James! You gave two advices at the prices of one :-). Now, I know the secret of "rounding". I tried to round amethyst Chips of the same size. Did not work well. Great tumbling and polish , but no rounding...I will use larger stones in the mix. Will mix 50/50 work? 50 - target stone mohs 7 and 50 % of stone for rounding and bigger size 1-1.5". Thank you again for detailed responses.
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jamesp
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Post by jamesp on Apr 5, 2017 2:45:25 GMT -5
I have been tumbling bigger rocks for years. The coarse grit does not last long because the bigger rocks simply grind harder and faster. Simple as that.
If the barrel was filled 100% with rocks as big as salt grains they would really take forever.
The grinding action takes place mostly in the avalanche at the top of the rocks in the barrel. That is where the larger rocks do their grinding by applying pressure.
Finishing and polishing does not require much grinding pressure.
60 % big rocks 40% smalls faster grind than 40% big rocks 60% small rocks. Big rocks being 1-2 inch rocks. Rocks bigger than 2-3 inches can start to damage each other and the chips. So if you want to speed the grind you could use 70% big(1 to 2 inch) rocks and 30% tanz chips.
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alecogeorgia
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Antithesis of tumbling - Friction retards progress
Member since January 2016
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Post by alecogeorgia on Apr 5, 2017 8:59:13 GMT -5
I have been tumbling bigger rocks for years. The coarse grit does not last long because the bigger rocks simply grind harder and faster. Simple as that. If the barrel was filled 100% with rocks as big as salt grains they would really take forever. The grinding action takes place mostly in the avalanche at the top of the rocks in the barrel. That is where the larger rocks do their grinding by applying pressure. Finishing and polishing does not require much grinding pressure. 60 % big rocks 40% smalls faster grind than 40% big rocks 60% small rocks. Big rocks being 1-2 inch rocks. Rocks bigger than 2-3 inches can start to damage each other and the chips. So if you want to speed the grind you could use 70% big(1 to 2 inch) rocks and 30% tanz chips. Great advice, Jamesp! THANK YOU. Do you have any insight on the degree of polish of the filler large stones? Shall they be tumbled already or rough is ok?
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jamesp
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Post by jamesp on Apr 5, 2017 9:44:37 GMT -5
Well, I would assume you are starting with tanz chips and 1-2 inch rocks that need rounding. They should round together about equally, in coarse grit. That means 6-12 weeks and adding coarse grit at least every week.
So the large rocks are as much the target as the chips. They both start out rough, and end up rounded, and then end up polished.
If the chips are rounding faster, then move the whole batch to the next step. Use the large rocks again on the next batch of tanz chips. After 2 runs the large rocks should be catching up in roundness. Basically the large rocks are the media and the chips are the target. It is the reverse, usually the small rocks are the media. In your case you want smalls as target. Nothing wrong with that.
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alecogeorgia
off to a rocking start
Antithesis of tumbling - Friction retards progress
Member since January 2016
Posts: 16
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Post by alecogeorgia on Apr 5, 2017 22:33:46 GMT -5
Well, I would assume you are starting with tanz chips and 1-2 inch rocks that need rounding. They should round together about equally, in coarse grit. That means 6-12 weeks and adding coarse grit at least every week. So the large rocks are as much the target as the chips. They both start out rough, and end up rounded, and then end up polished. If the chips are rounding faster, then move the whole batch to the next step. Use the large rocks again on the next batch of tanz chips. After 2 runs the large rocks should be catching up in roundness. Basically the large rocks are the media and the chips are the target. It is the reverse, usually the small rocks are the media. In your case you want smalls as target. Nothing wrong with that. Many thanx, Guru! :-)
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jamesp
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Post by jamesp on Apr 6, 2017 7:48:47 GMT -5
Well, I would assume you are starting with tanz chips and 1-2 inch rocks that need rounding. They should round together about equally, in coarse grit. That means 6-12 weeks and adding coarse grit at least every week. So the large rocks are as much the target as the chips. They both start out rough, and end up rounded, and then end up polished. If the chips are rounding faster, then move the whole batch to the next step. Use the large rocks again on the next batch of tanz chips. After 2 runs the large rocks should be catching up in roundness. Basically the large rocks are the media and the chips are the target. It is the reverse, usually the small rocks are the media. In your case you want smalls as target. Nothing wrong with that. Many thanx, Guru! :-) No stranger to the tumbling of chips. They can be real slow if you do not add 50% rounder 1-2 inch rocks. Most of these are 3/4 to 1.5 inch thin chips. They are a target of metal smithing one day. www.flickr.com/photos/67205364@N06/sets/72157649230302913
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SirRoxalot
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Post by SirRoxalot on Apr 8, 2017 10:32:43 GMT -5
I'd suggest using something softer and not too much bigger than the tanzanite. Maybe feldspar?
Tanzanite has perfect cleavage in two directions. You put agates in with that, and you might have a problem.
Might want to over-fill the barrel and keep a close eye, and ear on it.
A loud, hard, cascading action will surely ruin that tanz. If you've tumbled feldspar before, you'll understand.
Good luck, and please let us know how it works out. I've got a kilo of the stuff on order.
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alecogeorgia
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Member since January 2016
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Post by alecogeorgia on Apr 8, 2017 21:45:36 GMT -5
I'd suggest using something softer and not too much bigger than the tanzanite. Maybe feldspar? Tanzanite has perfect cleavage in two directions. You put agates in with that, and you might have a problem. Might want to over-fill the barrel and keep a close eye, and ear on it. A loud, hard, cascading action will surely ruin that tanz. If you've tumbled feldspar before, you'll understand. Good luck, and please let us know how it works out. I've got a kilo of the stuff on order. Ok. Thank you. I thought for a while and decided to use a mix of ceramic media, agate ( <=3/4"). I did "overfill" a bit with larger chips of my own amethyst of aquarium quality😁. The sound of tumbling is perfect for now. Will check every day to exclude surprises.
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alecogeorgia
off to a rocking start
Antithesis of tumbling - Friction retards progress
Member since January 2016
Posts: 16
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Post by alecogeorgia on May 6, 2017 14:45:28 GMT -5
Hello All who is interested.
I have completed my first experiment with tanzanite chips. The results are between satisfactory and good. Pros: I did not kill the stones. My output is around 75%. I got material lighter at the end and definitely polished. I am surprised that tanzanite is pretty hard, so next time I start with 60/90 grit. ( this time I started with 125). Cons: I expected more rounded corners, but my goal was not to get "nothing".
Conclusion: We can do it! Carefully! :-)
Thank you All for the advises. P.S. I cannot upload a picture. Error message says: this forum exceeded volume...:-)
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jamesp
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Post by jamesp on May 7, 2017 6:28:52 GMT -5
If they all survived without breaking I would increase the bigger rocks from 3/4 to average 1.5. I think you will speed your grind up a good bit.
Good move on moving to coarser 60/90. Chips are slow to round.
Glad you got close to your target.
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