Post by lacami on Apr 30, 2013 7:23:36 GMT -5
Hello!
Got some questions about how to progress with my very first batch of tumbled rock, namely sodalite. (Maybe a bit stupid to start out with a softer rock, buuut it's so pretty and I want to see how it turns out... )
I rather recently bought my first tumbler (a Lortone 33B) and started out with tumbling sodalite. Broke some of it with a sledgehammer to get some smaller pieces. I had about a pound, not enough to fill the barrel properly, so I added 2 deciliters (I think that's almost one cup) of plastic pellets, and so the barrel was 2/3 filled. Thought they might add some nice cushioning, too!
After a few days running with 2 tablespoons of 60/90 SiC (instructions I got recommended 3 for rocks with 7 in hardness and a bit less for softer rocks, so I took 2), I had a nice grey slurry. Ran it for a week, then added another tablesoon of grit because I couldn't feel any real pieces of grit in the slurry anymore.
Yesterday, after 17 days of tumbling, I decided to take them out and clean them and check how they were doing. And... they still have quite a lot of "layering", a few tiny holes and a some shallow cracks that won't seem to be ground away. (I guess those instructions recommending about a week in 60/90 grit and less if the rock is softer are all lies...? )
They weighed 480g when I started and now they weigh roughly 420g. Not very much ground away, is it? I read somewhere that one might expect 30% loss in the first stage, is that correct?
Anyway, a lot of background info there, sorry for that... xD Anyway, my basic question is, and I'm reaching out to all you lovely pros out there:
How to progress? Should I tumble them again with the plastic pellets? Or should I wait until I get some ceramic media? (Rather difficult to get in Sweden if you want the price to be decent, so I'm thinking about buying some from the US - even if you add shipping it'll be much cheaper than buying here xD)
I thought the pellets might help, apart from cushioning, with moving the grit around to the nooks and crannies of the rock and make it smoother. The sodalite is properly worn down, no sharp edges anywhere, but I want to remove those dents, because they'll surely catch tons of grit... plus I suppose those little dents won't be worn away in the 120/220 step, right?
I'd some really nice and smooth sodalites in the end since I'm planning to give a few of them bellcaps and make necklaces, so I don't want to continue in case I totally mess them up until I know a bit more about how sodalite behaves in rotary tumblers with 3lbs barrels. I'm prepared for failure though, its my first tumble session after all! ;D
Anyway. Advice is much welcome. How to remove those supertiny cracks and "layering"? Could it be that the plastic pellets cushioned too much so that the rocks didn't hit those places enough...? Maybe I used too little grit? (Or too much? xD) So difficult to know how much to really use with all the different instructions... ^^'
Thank you very much in advance!
// C
Got some questions about how to progress with my very first batch of tumbled rock, namely sodalite. (Maybe a bit stupid to start out with a softer rock, buuut it's so pretty and I want to see how it turns out... )
I rather recently bought my first tumbler (a Lortone 33B) and started out with tumbling sodalite. Broke some of it with a sledgehammer to get some smaller pieces. I had about a pound, not enough to fill the barrel properly, so I added 2 deciliters (I think that's almost one cup) of plastic pellets, and so the barrel was 2/3 filled. Thought they might add some nice cushioning, too!
After a few days running with 2 tablespoons of 60/90 SiC (instructions I got recommended 3 for rocks with 7 in hardness and a bit less for softer rocks, so I took 2), I had a nice grey slurry. Ran it for a week, then added another tablesoon of grit because I couldn't feel any real pieces of grit in the slurry anymore.
Yesterday, after 17 days of tumbling, I decided to take them out and clean them and check how they were doing. And... they still have quite a lot of "layering", a few tiny holes and a some shallow cracks that won't seem to be ground away. (I guess those instructions recommending about a week in 60/90 grit and less if the rock is softer are all lies...? )
They weighed 480g when I started and now they weigh roughly 420g. Not very much ground away, is it? I read somewhere that one might expect 30% loss in the first stage, is that correct?
Anyway, a lot of background info there, sorry for that... xD Anyway, my basic question is, and I'm reaching out to all you lovely pros out there:
How to progress? Should I tumble them again with the plastic pellets? Or should I wait until I get some ceramic media? (Rather difficult to get in Sweden if you want the price to be decent, so I'm thinking about buying some from the US - even if you add shipping it'll be much cheaper than buying here xD)
I thought the pellets might help, apart from cushioning, with moving the grit around to the nooks and crannies of the rock and make it smoother. The sodalite is properly worn down, no sharp edges anywhere, but I want to remove those dents, because they'll surely catch tons of grit... plus I suppose those little dents won't be worn away in the 120/220 step, right?
I'd some really nice and smooth sodalites in the end since I'm planning to give a few of them bellcaps and make necklaces, so I don't want to continue in case I totally mess them up until I know a bit more about how sodalite behaves in rotary tumblers with 3lbs barrels. I'm prepared for failure though, its my first tumble session after all! ;D
Anyway. Advice is much welcome. How to remove those supertiny cracks and "layering"? Could it be that the plastic pellets cushioned too much so that the rocks didn't hit those places enough...? Maybe I used too little grit? (Or too much? xD) So difficult to know how much to really use with all the different instructions... ^^'
Thank you very much in advance!
// C