MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 1, 2019 11:32:32 GMT -5
Now that I've started using plastic pellets for some of the later stages, I've noticed a strange issue. (This is a rotary tumbler)
if I use a certain amount of grit with ceramic media - after the tumbling period (let's say, a week) - I open the barrel and all the grit is used up. Hurray!
BUT... when I use the same size barrel, same amount of grit, and same time period, but use plastic pellets instead - at the end of the time period, a good portion of the grit in unused and just settled firmly on the bottom of the barrel. It's almost like the plastic pellets push the grit to the bottom and trap it there.
I wonder if I need to open the barrel and mix it up during the time period? Tumble it for longer? Use less grit? I do like that the plastic pellets keep the rocks from chipping and bruising during the later stages. However, it takes much longer and wastes grit when this happens.
Has anyone else experienced this? What did you do?
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Post by parfive on Jun 1, 2019 12:46:12 GMT -5
Just use less grit. Most of us cut back in later stages.
If you use four tablespoons of 60/90 (w/no pellets in coarse grind, right?), try three when you go to 500.
No, don’t bother. That’s what a rolling tumbler does all by itself. : )
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MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 1, 2019 13:08:39 GMT -5
Just use less grit. Most of us cut back in later stages. If you use four tablespoons of 60/90 (w/no pellets in coarse grind, right?), try three when you go to 500. No, don’t bother. That’s what a rolling tumbler does all by itself. : ) Well, this in particular is the 120/200 grit stage. I 'should' use the same amount that I normally would with ceramic media. When I do get to 500 or 1000, I cut that in half.
Also, of course this is a rotary tumbler, but even after tumbling for a week I have a large amount of sludge stuck to the bottom. Clearly the rotary action isn't really mixing it up as well.
What I'm saying is that - if all factors are the same - using the ceramic media seems to stir up the grit more effectively than with plastic pellets. I need to use the plastic for more delicate items, but I need to find a fix for this issue.
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Post by Garage Rocker on Jun 1, 2019 13:14:11 GMT -5
I'm a rotary first stage, then Lot-O guy, but do most people use ceramics until the pre-polish and polish stages? The plastic pellets being soft, I would expect them to inhibit the breakdown of grit, where as the ceramic pellets aid in grit breakdown.
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Post by parfive on Jun 1, 2019 13:39:00 GMT -5
The sludge isn’t stuck to the bottom while the tumbler is rolling, it just settles there when you stop tumbling and set the barrel down.
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Post by grumpybill on Jun 1, 2019 14:02:05 GMT -5
Grit will breakdown slower when you use plastic pellets or other soft material for "cushioning" because there is less grinding action.
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Wooferhound
Cave Dweller
Lortone QT66 and 3A
Member since December 2016
Posts: 1,422
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Post by Wooferhound on Jun 1, 2019 23:40:08 GMT -5
Which side is "the bottom" when it's rolling on the tumbler ?
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MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 2, 2019 10:10:12 GMT -5
Which side is "the bottom" when it's rolling on the tumbler ? Well, it would be the actual bottom when taking off the roller and set down. The sludge is so thick and firm there that it wouldn't make sense to get that way just in the one minute I've had it set down before rinsing. It had to somehow get shoved over to the "side" while tumbling and got all packed over there. I add grit last, so it's not like I added grit first on the "bottom" and it just stayed there after I started tumbling. Strange.
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MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 2, 2019 10:11:07 GMT -5
The sludge isn’t stuck to the bottom while the tumbler is rolling, it just settles there when you stop tumbling and set the barrel down. It's pretty settled and a little compact, which dossn't make sense to get into that state in the minute or two after I take it off the roller and pour it into the strainer....
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MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 2, 2019 10:11:44 GMT -5
Grit will breakdown slower when you use plastic pellets or other sift material for "cushioning" because there is less grinding action. This does make sense. I guess I'll just have to plan to tumble longer in each stage that I use plastic pellets - Thank you!
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Post by Rockindad on Jun 2, 2019 10:30:10 GMT -5
Which side is "the bottom" when it's rolling on the tumbler ? Well, it would be the actual bottom when taking off the roller and set down. The sludge is so thick and firm there that it wouldn't make sense to get that way just in the one minute I've had it set down before rinsing. It had to somehow get shoved over to the "side" while tumbling and got all packed over there. I add grit last, so it's not like I added grit first on the "bottom" and it just stayed there after I started tumbling. Strange. You might be surprised how fast this can happen, especially if your slurry is on the thin side and the grit particles are not trapped in suspension. A single minute is more than enough time. Al
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Post by greig on Jun 2, 2019 10:39:38 GMT -5
Any chance that the amount of water is incorrect? It can be difficult to tell because the plastic beads float.
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Post by Rockindad on Jun 2, 2019 15:47:47 GMT -5
We just finished recharges on a bunch of rotary barrels and wanted to see just how fast the grit inside could settle. The barrel we chose had 60/90 SiC, Banded Amethyst and some ceramics along with a bit more water than we would normally use. It was last recharged 5 days ago. We did not plan on opening this until next weekend because of an extremely busy week coming up, so we knew this one would be a bit more watery. After taking this barrel off of the tumbler I let it sit with the lid facing up until I removed the lid and grabbed a small bucket to dump the contents of the barrel into. I'll say this took 30-45 seconds as our setup is pretty streamlined. After dumping the barrel there was a solid layer of grit/ceramics/stones stuck to the bottom. While the grit was breaking down and finer than 60/90 the particles were heavy enough to settle out of the thinner than usual slurry in that very brief period of time.
Al
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MommaGem
spending too much on rocks
Member since April 2019
Posts: 312
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Post by MommaGem on Jun 2, 2019 16:22:58 GMT -5
We just finished recharges on a bunch of rotary barrels and wanted to see just how fast the grit inside could settle. The barrel we chose had 60/90 SiC, Banded Amethyst and some ceramics along with a bit more water than we would normally use. It was last recharged 5 days ago. We did not plan on opening this until next weekend because of an extremely busy week coming up, so we knew this one would be a bit more watery. After taking this barrel off of the tumbler I let it sit with the lid facing up until I removed the lid and grabbed a small bucket to dump the contents of the barrel into. I'll say this took 30-45 seconds as our setup is pretty streamlined. After dumping the barrel there was a solid layer of grit/ceramics/stones stuck to the bottom. While the grit was breaking down and finer than 60/90 the particles were heavy enough to settle out of the thinner than usual slurry in that very brief period of time. Al Thanks for the test - That's great information!!
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Wooferhound
Cave Dweller
Lortone QT66 and 3A
Member since December 2016
Posts: 1,422
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Post by Wooferhound on Jun 3, 2019 13:15:20 GMT -5
Same thing again here . . .
Sounds like too much water to me.
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