mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Oct 4, 2023 9:25:40 GMT -5
I tried to tumble a large 5-6 inch "yooperlite" in a 12lb barrel. I filled the rest of the barrel up with 1/2 inch pea gravel, plus 12 tbsp of 46/70. I used a little extra water since there is softer mudstone/limestone rocks in the pea gravel.
After a week, I got practically no grind at all, not even the gravel looked ground down. The slurry was watery and there was a lot of unused grit.
This is a first... where did I go wrong here? Too much water? Too much filler?
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rocknewb101
fully equipped rock polisher
Member since October 2022
Posts: 1,368
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Post by rocknewb101 on Oct 4, 2023 9:30:36 GMT -5
Could the large difference in size be a contributing factor? So instead of 1 large and a bunch of tiny, should there be medium in there too? I'm not sure, I'm just throwing out thoughts...I have never tumbled one large rock before so I don't have that experience.
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Post by HankRocks on Oct 4, 2023 10:10:21 GMT -5
When you are in the grinding mode you do need a assortment of rock sizes. It's just physics, when grit is between the large piece and all the smalls, the smalls will tend to move out of the way sparing the grit particles from being broken down much and not doing much grinding. When contacting larger rocks, they will not move out ot the way as much and there will be grinding and more grit breakdown. After I have any large pieces shaped as I want them in the 1st and 2nd stage(220 SiC), I move them to a batch consisting of one really large piece along with all previously run and shaped smalls. That in my 600Sic, 500 AlO and Polish stages. I have run several med large together in the 15 pound barrel and the UV-18 assuming the collisions between them will be less frequent. My favorite large, pictured below, ran using this method. The piece is English Ballast Flint from an un-disclosed location on the U.S. East Coast, has about the best polish I have managed to produce. If you zoom in you can see one of the Hubble deep space views of faraway galaxies. IMG_3840 by Findrocks, on Flickr
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mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Oct 4, 2023 11:29:59 GMT -5
Beautiful polish! Very nicely done. You should be proud of that one! I figured the weight of the large rock would be enough to produce a grind. I guess not. I guess if you think about it, all similar size smalls would be equally pushing away from each other, rather than grinding into each other, despite larger rock in the barrel. I was trying to gently grind the large yooperlite because it has lots of fractures in the syenite matrix. I wanted to minimize bruising. I'll try again with some medium sized rock in the mix. I thought all small gravel in the course stage would act similar to ceramics as used in finer stages. I guess this shows a good difference between grinding and polishing. I've polished larger rocks before, but there were a mixture of sizes.
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dshanpnw
fully equipped rock polisher
Member since December 2020
Posts: 1,071
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Post by dshanpnw on Oct 5, 2023 8:51:31 GMT -5
Maybe too much water. Maybe you can let it run until all the grit is used up, maybe two weeks before checking it. I'm thinking you filled the barrel to 3/4 full. What does the pea gravel look like? I have tumbled a large piece of rose quartz (3-4 inches) with a large agate (3-4 inches) together in a 12 pound barrel filled with ceramic media. It took a very long time, but it worked. I just started tumbling a pretty big chunk of carnelian yesterday in a 12 pound barrel. It is mixed with other rocks of all different sizes to 3/4 full. I'm just trying to grind enough to see what the carnelian looks like beneath the rough surface. I'm anxious to see if that mix in the barrel works out or not.
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mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Oct 5, 2023 12:34:20 GMT -5
Maybe too much water. Maybe you can let it run until all the grit is used up, maybe two weeks before checking it. I'm thinking you filled the barrel to 3/4 full. What does the pea gravel look like? I have tumbled a large piece of rose quartz (3-4 inches) with a large agate (3-4 inches) together in a 12 pound barrel filled with ceramic media. It took a very long time, but it worked. I just started tumbling a pretty big chunk of carnelian yesterday in a 12 pound barrel. It is mixed with other rocks of all different sizes to 3/4 full. I'm just trying to grind enough to see what the carnelian looks like beneath the rough surface. I'm anxious to see if that mix in the barrel works out or not. The extra water certainly is possible. Most of my gravel mix is pretty heavy with limestone and other soft rocks. I use it regularly in other barrels as a cushion with a mixture of tumble sizes and it works very well. In those barrels, I usually add a bit extra water (usually to about 1" to 1 1/2" below top of rocks), otherwise the slurry will turn to pudding. This time, I added extra-extra water expecting the multitude of small gravel to make a VERY thick slurry. The opposite happened. Here's a pic before, extra water to the very top of the rocks. I was expecting a super-thick slurry from the new pea gravel. 3/4 full (even though the photo looks weird). This is a photo of a completely different previous run in a 6lb barrel that turned to complete muck. This used the same pea gravel. I was trying to avoid this situation by adding the excess water in my 12lb yooperlite run.
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Post by chris1956 on Oct 5, 2023 15:44:20 GMT -5
Maybe too much water. Maybe you can let it run until all the grit is used up, maybe two weeks before checking it. I'm thinking you filled the barrel to 3/4 full. What does the pea gravel look like? I have tumbled a large piece of rose quartz (3-4 inches) with a large agate (3-4 inches) together in a 12 pound barrel filled with ceramic media. It took a very long time, but it worked. I just started tumbling a pretty big chunk of carnelian yesterday in a 12 pound barrel. It is mixed with other rocks of all different sizes to 3/4 full. I'm just trying to grind enough to see what the carnelian looks like beneath the rough surface. I'm anxious to see if that mix in the barrel works out or not. The extra water certainly is possible. Most of my gravel mix is pretty heavy with limestone and other soft rocks. I use it regularly in other barrels as a cushion with a mixture of tumble sizes and it works very well. In those barrels, I usually add a bit extra water (usually to about 1" to 1 1/2" below top of rocks), otherwise the slurry will turn to pudding. This time, I added extra-extra water expecting the multitude of small gravel to make a VERY thick slurry. The opposite happened. Here's a pic before, extra water to the very top of the rocks. I was expecting a super-thick slurry from the new pea gravel. 3/4 full (even though the photo looks weird). This is a photo of a completely different previous run in a 6lb barrel that turned to complete muck. This used the same pea gravel. I was trying to avoid this situation by adding the excess water in my 12lb yooperlite run. Too much soft rocks? That is what the second photo makes me think as thick as it is. Can you take the soft ones out and try it with that?
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dillonf
fully equipped rock polisher
Hounding and tumbling
Member since February 2022
Posts: 1,622
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Post by dillonf on Oct 5, 2023 21:17:38 GMT -5
That top pic definitely makes me think too much water is the culprit. I up my water volume sometimes when I am gonna let the barrel run for 3 weeks straight, but I have never used that much water.
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dshanpnw
fully equipped rock polisher
Member since December 2020
Posts: 1,071
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Post by dshanpnw on Oct 6, 2023 7:14:42 GMT -5
I definitely understand why you thought more water would help after seeing that paste/not slurry surprise. Holy moly, I've had that happen a couple times. That's probably from the soft rock debris. You shouldn't mix soft rocks with harder rocks. Your rocks should all be about the same hardness on the Mohs scale, 6.5 to 7.0, or all softer rocks, 5.5 - 6. The soft ones will not help grind the harder ones. Change your pea gravel to ceramic media and you'll get better results, promise.
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mgroothuis
starting to spend too much on rocks
Member since November 2022
Posts: 166
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Post by mgroothuis on Oct 6, 2023 17:06:31 GMT -5
I definitely understand why you thought more water would help after seeing that paste/not slurry surprise. Holy moly, I've had that happen a couple times. That's probably from the soft rock debris. You shouldn't mix soft rocks with harder rocks. Your rocks should all be about the same hardness on the Mohs scale, 6.5 to 7.0, or all softer rocks, 5.5 - 6. The soft ones will not help grind the harder ones. Change your pea gravel to ceramic media and you'll get better results, promise. Yeah, the thick slurry mishaps really suck! Most of my tumbles are only hard rocks, unless I'm doing something out of the ordinary like petoskey or lightning stones. I generally only use the pea gravel mix when there's larger, heavy rocks in the barrel. I tend to tumble rocks larger than 2-4 inches quite often. Sometimes larger. So, the softer gravel does a few things for me: Obviously, it's softer. It cushions the harder large rocks in my barrels preventing bruising on my smaller rocks in the barrel. Plus it usually forms a pretty nice slurry that coats everything, kind of like Borax in the vibe. The grit is nearly always used up after a week with pretty good results. Plus, when I dump the slurry in buckets, the the pea gravel slurry separates into pure water on top and thick precipitate at the bottom. The clear water can go right down the drain, and I can quickly dry the rest for the weekly trash can. It makes slurry disposal so much easier. I do use ceramic media, but only entering the next stage with 120/220 SiC. I couldn't afford it in the rough stage with 10 barrels running at a time. haha
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dshanpnw
fully equipped rock polisher
Member since December 2020
Posts: 1,071
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Post by dshanpnw on Oct 7, 2023 7:07:49 GMT -5
Looks like you have a good process to keep up with that many barrels. Your slurry disposal is similar to how I do it. Thanks for posting.
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