w9nl
off to a rocking start
Member since January 2011
Posts: 3
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Post by w9nl on Jan 3, 2011 12:15:31 GMT -5
First post and first batch. I have been spending lots of time on the Southwestern shores of lake Michigan this past year and recently picked up a Lortone 33B tumbler. I'm doing 2 batches right now. One is with smoother rocks and I started that with 220 grit. I read I should tumble with this for about a week, but I'm wondering if this is too long for rocks that are smooth to begin with.
I have another batch going with 80 grit on stones that were more rough. But even these might be considered smooth considering the pictures I have seen from what some of you are starting with. So I'm wondering if I should go a week wit those as well.
I'm interested in any input and figure this first batch is trial and error so no biggie if these don't quite come out right. I clearly don't know my rocks at this point but I did try to stay away from the softer ones.
Thanks!
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Post by jakesrocks on Jan 3, 2011 12:26:09 GMT -5
I use a Thumlers Model - B tumbler, and run everything for a solid month in 60/90 grit. The grit will continually break down into finer grit. At the end of the month my rocks look like they've just come out of pre-polish. I think you'll find that there are almost as many opinions about tumbling times, as there are members on here. Since this is your first batch, experiment a little, and keep good notes on what you try. Post pics of your results, and the hard core tumblers on here will be able to advise you better than I can. Just to give you an idea, here's a link to a post I made. forum.rocktumblinghobby.com/index.cgi?board=trtphoto&action=display&thread=41706This was 1 month in 60/90 grit. 3 weeks in 220 grit. 2 weeks in 600 grit, and 1 week in cerium oxide. Between each stage I tumble them for 4 to 6 hours in Borax, and rinse them real good. I use a bunch of plastic pellets in pre-polish and polish. Don
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Post by Hard Rock Cafe on Jan 3, 2011 13:14:02 GMT -5
Welcome to the board!
It's not possible to run rocks too long in any stage without recharging. As Don said, the grits break down. Longer early stages lead to rounder stones. Patience is everything in tumbling.
Chuck
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w9nl
off to a rocking start
Member since January 2011
Posts: 3
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Post by w9nl on Jan 3, 2011 13:49:30 GMT -5
Thanks for the replies, but this is my first batch....I have no patience I'll figure out how to post a image and show what I started with. I guess my overall concern with the 80 grit batch was that since these rocks were somewhat smooth to begin with, would a whole week really grind them much smaller. I've taken a peek, but haven't comapred to the original pictures I took.
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Post by jakesrocks on Jan 3, 2011 14:15:20 GMT -5
Patience is the key to successful tumbling. You can't rush it. An extra week or so in rough won't reduce the size of your stones that much, unless you're tumbling soft stone. It just takes the sharp corners off, and smooths out the overall appearance of the stones. Don
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Post by deb193redux on Jan 3, 2011 16:46:43 GMT -5
The problem is that it is almost impossible to evaluate the phrase "somewhat smooth." this could mean anywhere from somewhat rounded to highly rounded and showing a sheen. It also does not preclude a crack or fissure on an otherwise smooth surface. If you are OK with the fissure and want to polish the rest, thats one thing. If you want to remove the fissure, then it could take weeks depending on how deep it is.
Pictures really are essential, but also a clear statement about how much perfection you want in the tumbled stone surface.
Lake superior agates are known to be very hard. In most cases an extra week in course will not be very noticeable.
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w9nl
off to a rocking start
Member since January 2011
Posts: 3
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Post by w9nl on Jan 3, 2011 16:55:59 GMT -5
Hopefully the attachment comes thru OK. Bottom line is after looking closer at this rock I can clearly see the week or more timeframe being essential. I started this Saturday evening and I can see some overall smoothing, but some of the cracks/fissures are very evident. The problem is that it is almost impossible to evaluate the phrase "somewhat smooth." this could mean anywhere from somewhat rounded to highly rounded and showing a sheen. It also does not preclude a crack or fissure on an otherwise smooth surfact. If you are OK with the fissure and want to polish the rest, thats one thing. If you want to remove the fissure, then ite could take weeks depending on how deep it is. Pictures really are essential, but also a clear statement about how much perfction you want in the tumbled stone surface. Lake superior agates are known to be very hard. In most cases an extra week in course will not be very noticable. Attachments:
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Post by deb193redux on Jan 4, 2011 17:30:26 GMT -5
Thanks the pic helps a lot. Yes, I see that the angular edges and pointy bits on some rough people start with are indeed already rounded smooth. So the shape is fairly smooth (with some undulations and bulges, but no deep valleys, folds, or sharply angled planes) - BUT the surface is not smooth because there are some pits and cracks/flakes. Bad news is that I would not call this an agate. (Initially I thought you meant the banded agates folks call 'Lakers'). I would call it a granite. Like a agate there is a lot of silica, but it looks to be in the form of quartz (or maybe some feldspar), which is more macrocrystalline vs micro-crystalline, and there is an amalgam of other minerals (the black bits). You could use an extended grind to further perfect the shape if you wanted to get rid of the bulge I reflect on the right as well as other smaller undulations. Unfortunately I think that as you grind off the cracks and pits you see you will have new flaws exposed. The black bits appear Tobe more flaky, like a mica, and little bits are just going to pop out easily. Also the black bits and the black/orange contacts seem to have pits or scaly/crystally/whitish areas, and I think these go throughout the stone. Some of the cracks might be removed if they are due to the stone banging around in the wild. But they too might be throughout. If you want to shine up what you can, I would grind another week or two to see if you are getting less cracks. Then I would move it through the stages, washing the grit out of the pits very carefuly between each stage. I would use a lot of pellets to keep the black bits from getting knocked out so easily. In the end you should get a shine on some of the translucent orange parts.
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