ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 18, 2021 17:53:16 GMT -5
I've noticed that a lot of people use aluminum oxide grit for the 500 (3rd) stage in their vibes. I know that silicon carbide breaks down into shards and keeps grinding, while aluminum oxide breaks down into little balls. So does it just depend on the hardness of the rocks you have in your vibe?
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Post by Rockindad on May 18, 2021 19:06:12 GMT -5
It's great that you clearly have been reading up, I think a lot of people miss out when they ignore the wealth of information accumulated here when they only focus on the current threads. The way each of these breaks down also affects what they can do to the rocks. For instance there are members here who run 500AO in their vibes and let it break down until it is fine enough for polish.* I never liked the results enough to stop there and have always gone onto polish, sometimes throwing in a 1000AO step as well (typically for softer stones). I have never seen 500 SiC get close to that no matter how long the run, real nice matte finish is about it.
*I think this works a lot better in the rubber barrel of the Lot-O than a harder bowl like the UV-10, though I run my 500 in the same bowl as the 120/220SiC.
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 18, 2021 19:35:23 GMT -5
Thanks, Rockindad , for the reply. It's good to hear from someone that has a experience with different tumblers and vibes. Today, I switched my Lot-O vibe from the 150/220 silicon carbide grit to the 500 silicon carbide, BUT I also have some 500 aluminum oxide grit. Do you think I should rinse everything and switch over to that?
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on May 18, 2021 19:42:47 GMT -5
The 500 AlOx works so well in the vibe (Lot-O) that I have no desire to even try 500 SiC. If anything, I am tempted to try a larger grit aluminum oxide in place of the 120/220 grit silicon carbide just to see how it works in the vibe so that I could only use AlOx in the Lot-O and leave the silicon carbide only for the rotary.
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 18, 2021 20:18:34 GMT -5
So, I'm kind of surprised that in a machine that in a machine that breaks grit down so quickly, everyone uses the grit (aluminum oxide) that stops grinding sooner. Sorry I'm just looking for a solid reason here, not just blind faith. LOL I'll gladly try both if anyone is curious.
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 18, 2021 20:28:59 GMT -5
Of course, if my batches turn out different using different types, then I'll still ponder the reason; so I guess the joke would be on me! 😆
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on May 19, 2021 7:36:23 GMT -5
So, I'm kind of surprised that in a machine that in a machine that breaks grit down so quickly, everyone uses the grit (aluminum oxide) that stops grinding sooner. Sorry I'm just looking for a solid reason here, not just blind faith. LOL I'll gladly try both if anyone is curious. I’d be curious to learn how they compare. Assuming you have achieved good shaping in coarse and your second stage, the third stage is mainly a scratch eliminating step. Both silicon carbide and aluminum oxide should be good at eliminating the scratches from the previous stage. However, if you are working with very hard rocks, I could see how silicon carbide may edge out aluminum oxide in removing those scratches more quickly. I would guess that if you compared a batch run in 500 grit silicon carbide to a similar batch run in 500 grit aluminum oxide, the differences should be minimal, with the silicon carbide batch having a more frosted appearance and the aluminum oxide having a shinier appearance due to more polishing action occurring as the aluminum oxide rounds off. Please post some pictures if you do compare! I love a good experiment! 👍
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 19, 2021 9:36:18 GMT -5
brian , I love a good experiment, too! So, when I checked my Lot-O this morning, the rocks had been in with 500 silicon carbide grit for 12 hours. The slurry had definitely thickened, and I had to add more water. So, there is some significant grinding going on. I emailed The Rock Shed since they sell both types of 500 grit and list them for rotary or vibratory tumblers; so we'll see what they say. If it is wrong to use the 500 SiC, I can switch them over to the 500 AlOx at a moment's notice. I have noticed on YouTube videos that after the 500 AlOx stage, the rocks look pretty shiny when dried. I bet that will not be the case with the 500 SiC. I also was googling this topic, and found that thegemshop.com recommends the 500 SiC grit for the vibe, but they are also using a different vibe - the Tumble-Vibe. Sorry for all the random thoughts - I just think it's interesting!
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Brian
fully equipped rock polisher
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Post by Brian on May 19, 2021 10:13:15 GMT -5
Random thoughts are the best! I just started a batch in the Lot-O last night in 500 grit aluminum oxide. I pulled out this chunk of poppy jasper that I was tumbling to see how it would finish, so this provides a nice big surface for some comparisons. It’s not shiny yet, but it certainly looks like it may be by the time the 2 day cycle is done. If I remember, I will try to take more pictures tomorrow evening. I took some shots in bright sunlight and in the shade so hopefully you can tell what the surface looks like. Edited to add that this rock was never put in coarse. I started it in the vibe using 120/220 SiC simply because I am not yet sure what I want to do with it yet but I wanted to see what kind of finish it will take.
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 19, 2021 10:56:27 GMT -5
Shawn from The Rock Shed just replied to me:
"Thanks for the note. So I think you could use either in a vibe but SIC may become embedded into poly barrels more easily than Aluminum oxide. We feel that the AO actually works a little faster than the sic. We started selling AO because SIC was going up in price but after using it, we liked it better."
So now we know! 🙃
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ericabelle
spending too much on rocks
Instagram acct: @erica_shoots_everything
Member since April 2021
Posts: 482
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Post by ericabelle on May 19, 2021 11:03:54 GMT -5
Beautiful jasper, brian ! I bet that will be gorgeous polished since it is already beautiful! I posted Shawn's reply (from The Rock Shed) above. If the aluminum oxide works faster, I may switch my barrel over to it now. (I had already put 500 SiC in the barrel before I started this thread yesterday.) OR I could continue with my experiment. Sounds like the results may be about the same. Hmm.... Decisions, decisions! Since this is my first time using my Lot-O, if the rocks don't have a mirror shine it's probably going to be a "user error" anyway! 😂
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on May 19, 2021 19:18:19 GMT -5
Thanks for posting Shawn's reply. I have to say I'm a little surprised that AlOx may actually work faster than the SiC. Although that may mean that getting to the finished product may be faster if the aluminum oxide gets a head start on the polishing.
And thanks for the compliment on the jasper! I really love how this one looks already that I want to do as little to it as possible.
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,512
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Post by Brian on May 20, 2021 17:52:33 GMT -5
Here are some photos of that same rock after 48 hours in 500 grit aluminum oxide. It wasn’t a perfect run since it dried out too much overnight due to the warmer weather. I’m guessing it would look even better had I given it any time in coarse rather than just a couple days in 120/200.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
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Post by Benathema on May 20, 2021 21:53:53 GMT -5
I reckon your 120/220 SiC has passed 500 by the time you reset for 500. May have something to do with the AO seeming faster.
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