hkswrapsody
starting to spend too much on rocks
Member since June 2008
Posts: 109
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Post by hkswrapsody on Jun 24, 2013 10:39:09 GMT -5
I could seriously use some advice if someone can help. I cut a bunch of cabs, agate, shaped and polished to 900 grit on my grinding wheels. I wanted to try to finish polishing in a vibratory tumbler. The next grit size I have available is 600 grit. I added quite a bit along with tiny ceramic pellets as filler. My slurry now looks like pancake batter and it has been going for twelve hours. How long should I expect to run this batch, agate? What should I be looking for in surface texture to let me know when it is ready for polish. Will I expect to see any shine at all. So far I see a uniform surface with no shine at all. I have a separate bowl for polish. Do I use ceramic bits in the polishing step? The only other media I have is walnut shell. I am aware cleanliness is also an important factor between steps.
In the kit I purchased I have only the polishing media provided, I do have cerium if this is better and soap. If anyone can help me know what I am looking for most importantly to proceed to the polishing step and if I should use the ceramic bits or walnut shell would be most helpful. I have no plastic pellets at this time for filler. Simple observations for this very confused newbie would be appreciated. There are so many different opinions that I am quite confused at this time.
Thanks, Helen
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Post by Jugglerguy on Jun 24, 2013 11:32:24 GMT -5
I'm not sure what size vibratory tumbler you have, so you might have to adjust what I use for your situation. I have a Lot-O tumbler which holds about 4.5 lbs. I only use 1/2 tsp. of grit in each step after 220. I use 2 TBSP of 220, but you're already past that stage. I also use 1 tsp of Dreft laundry soap in each stage. You should have almost no water in the tumbler. I fill my tumbler to the top and then put my hand over the top as a sort of colander and tip all the water out. The rocks are then wet, but there's no water sitting in the bottom. I would let the 600 grit run for about 2 days. The grit will break down to half the size in about 12 hours, so after 12 hours, your 600 grit will become 1200 grit. After another 12 hours it will be 2400 grit. My rocks are usually getting shiny after a couple days in 600 grit.
The next stage I do is 1000 grit (1/2 tsp.) for two days, with Dreft. Without washing, I add 1/2 tsp. of tripoli after two days in 1000, but I don't think most people do this step. It's been working for me, so I keep doing it. I let the tripoli run for another 2 days.
Then I wash the rocks and put them back in the barrel with Dreft and about 1/2 cup water and run for about 5 hours to really clean them before polish. Then I switch to my polish barrel for 2-3 days in aluminum oxide polish.
You mentioned that your slurry looks like pancake batter. My slurry is all stuck to my rocks since I use very little water. It's gray and thick enough to stick to the rocks. I only add a little water from a squirt bottle if the rocks stop moving. In my Lot-O, they slowly rotate around, so you see them moving when you open the top. When the slurry gets too thick, they vibrate, but don't rotate from top to bottom. That's when I know I need to add water. I rarely add water in any other stage than 220. In 220, you're removing more material from the rock which thickens the slurry. In the other stages, you're not removing much material and the grit keeps breaking down, so it doesn't thicken the slurry much.
I almost forgot about the ceramic media. I always use ceramic in the vibratory tumblers at all stages. I use at least about 20%, but more if the rocks are more fragile, like obsidian for example. I've never used walnut shells. Plastic pellets don't work well in a vibratory tumbler from what I've read. Agate is about the easiest rock to get a shine on and should only require about 20% ceramic, or maybe even none at all. I've never polished cabs though, so you might need a lot more to protect them. Its always a good idea to have a variety of sizes in the tumbler, so ceramic will accomplish that since your cabs might be all the same size. You also probably don't have enough cabs to fill the tumbler, so ceramic will fill it. I always run my Lot-O filled right up.
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hkswrapsody
starting to spend too much on rocks
Member since June 2008
Posts: 109
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Post by hkswrapsody on Jun 24, 2013 11:51:08 GMT -5
I have a 3 lb vibe tumbler and I used quite a bit of ceramic bits to cushion cabs and to bring volume up or tumbler. The rocks appear well coated with very little water at bottom of tumbler. I did pour off as much excess water as I could. If I read correctly I should expect to see some shine after 48 hours. I chose agate because it usually is fool proof.
Thanks for the advice and I will certainly follow it as carefully as I can. Having never done this I just needed a little help trying to visualize what cabs would look like after 600 grit. I bought a tumbler and wanted to experiment a bit with other techniques just for fun.
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Post by Bikerrandy on Jun 24, 2013 16:28:22 GMT -5
Your agate cabs should look flawless, with a frosty to semi gloss finish. By flawless, I mean no visible scratches whatsoever. 12 hours might be plenty, rinse a few of them and let them dry to get a good look. If there are any scratches, run them for another day in the same slurry and check again until you're satisfied. If you're happy with them, rinse them really good and tumble in Borax (or ivory soap shavings) for 4-6 hours, rinse and go to the polish stage. If for some reason you're not happy with them after a day and a half in 600, rinse and run them again in some fresh 600.
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hkswrapsody
starting to spend too much on rocks
Member since June 2008
Posts: 109
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Post by hkswrapsody on Jun 24, 2013 16:57:11 GMT -5
Thanks, actually they look frosty with no visible scratches right now. No real visible gloss though. I will let them go overnight just to be sure and follow your cleaning procedure and then polish according to the nice person's instruction above. Maybe I'm being overly cautious but cutting all those cabs was time consuming. I hate to to ruin them because of my own ignorance.
Thanks so much
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Post by Bikerrandy on Jun 24, 2013 19:09:08 GMT -5
Nothing wrong with overly cautious, patience always pays off. Here's another hint, especially with agates, I vibe mine in the polish for a minimum of 7 days (although the manufacturer instructions say 2-3). They will get shinier every day. On the 7th day, rinse them off and run them in Borax again for another 4-6 hours. Agates will come out with a mirror shine every time
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hkswrapsody
starting to spend too much on rocks
Member since June 2008
Posts: 109
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Post by hkswrapsody on Jun 24, 2013 22:23:10 GMT -5
Thanks for all the help
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