swagle
off to a rocking start
Member since September 2009
Posts: 3 
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Post by swagle on Sept 23, 2009 14:48:43 GMT -5
My wife and I went to a gem mine (our first one) in North Carolina, and came back with several bags of gems. We decided to buy a rock tumbler. I bought one way too big, but that's ok. We put our soft stones together and started our process. We skipped the first coarse grit per the instructions for soft stones, and used river rock to fill the rotary tumbler 3/4 the way up. We were happy with the results. After the first week, we went to the pre polish stage. After another week we were happy with the results. Our final polish, however, looks the same as our pre polish. We were very careful to clean everything between steps, so I do not know what went wrong, but we have harder stones to tumble next and I do not want to ruin them. Is there anything that can be done with the stones I have, and what did we do wrong? Thanks
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Post by Toad on Sept 23, 2009 15:02:59 GMT -5
Sometimes softer stones don't take a good polish, but more a matte finish. What are you tumbling, and what polish did you use? Someone here is bound to know a polish that might work better for you.
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Post by tkrueger3 on Sept 23, 2009 15:05:54 GMT -5
Couple of things - first, what specific polish are you using for your final polish? For softer stones, often tin oxide works well. Second, a lot of "river rocks" and "beach rocks" simply will never polish - that may be the case with your rocks.
Hope this helps, but I'm sure you'll get better answers from the more learned members here - sabre52 (Mel), among others.
Tom
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Post by deb193redux on Sept 23, 2009 15:10:56 GMT -5
If I understand, the river rock was just filler. As Todd noted, what are the gemstones you wanted to polish?
Unless the gemstones were soft too, I am unclear on skipping the course step.
Anyway, with more details, I am sure there would be more advice.
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Post by Jack ( Yorkshire) on Sept 24, 2009 2:47:28 GMT -5
Swagle
Try a burnishing run of 24hr min in Borax and Ivory (Soapflakes)
This is best done befor the polishing stage
So I would go back and give them a 1000 0r 1200 Grit run first wash, then a burnishing run 24 to 48 hours then wash and do another good polishing run
Any Sharp broken bits in the barrel ? after polishing
IF you have river rocks that are polished (even if not to good ) keep in the batch, other softer Beach rocks could be causing a problem so discard try and have a barrel of same hardnesses.
Try a different Polish CO or TO ? which do you use ?
AS Tom says above TO works better on softer stuff
Jack
Yorkshire UK
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Post by frane on Sept 24, 2009 7:23:21 GMT -5
I always use a separate barrel for only polish also. It is extra expense but your rocks will have less chance to have barrel contamination in your polish step.
As others have said, some softer rocks will only get a matte finish at their best.
Fran
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Post by Hard Rock Cafe on Sept 24, 2009 11:06:42 GMT -5
In a mixed load of hardness, the harder rocks will polish but the softer ones will not. If your beach/river rocks are harder than your gems, your gems will not polish (but the beach/river rocks will).
Chuck
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Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,497
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Post by Sabre52 on Sept 24, 2009 13:11:28 GMT -5
I think all the other folks have already covered most the points but the ,most important question asked was, What kind of soft stones are you tumbling and how soft are they? Porosity is a factor too as is the grain size in the rough. Rocks that are granular or too porous will never take more than a mat finish , if that. If water is absorbed when you wet the rough rocks rather than beading up, you've got a problem. Also rocks below about mohs 3-4 or of mixed hardness due to their mineral makeup are very tough to polish beyond a matte finish. As someone has said, mixed hardness loads are problematic too as the harder rocks grind away and beat up the softer. Your river rock filler may be harder than your target stones. Best bet is have a dedicated barrel for polish/ prepolish or each stage if possible ( that's what I do) to avoid cross contamination and stick to stones of similar hardness for each batch.....Mel
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Post by MyNewHobby on Sept 25, 2009 18:05:55 GMT -5
The only time(s) okay .... more than one .... when I have had the matte finish/issue is the Rainbow obsidian when I was not tumbling it with its own kind and Wonderstones.
When I finally did the final polish of the obsidians together, the polish came out great!
Julie
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Post by Toad on Sept 25, 2009 18:15:02 GMT -5
Hmmmm, guess swagle didn't want to know that bad after all...
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swagle
off to a rocking start
Member since September 2009
Posts: 3
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Post by swagle on Sept 27, 2009 11:32:39 GMT -5
I think the rocks we are concerned about are fluorite and sodalite. As I said before we are beginners. We bought a book about gems and tried to separate the gems into hardness categories. The rest were just fill rock, though many of them turned out to be great looking stones. I do not know what the materials were, all the grit and polish came with the tumbler, and had no names. The tumbler appears to have been home made, though it is very well built, and the instructions and the grit/polish were inside. I think the size is 1 gallon. The instructions that came with the tumbler said that on softer stones the first coarse grit step could be skipped. I have to admit that everything in the instructions was dead on except the final polish step. I think that answers everyones questions. Do you think it was operator error, or is there something else to be done. It does not appear to me that anything changed between the pre polish and the final polish. Thanks in advance for your help.
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Post by tkrueger3 on Sept 27, 2009 12:06:24 GMT -5
Here's my 2 cents: I've been tumbling both sodalite and flourite. My advice - do NOT mix anything else with either the sodalite or the flourite. And with the flourite, be careful with the coarser grits - flourite is so soft that the coarse grits will eat it up very quickly. One batch of mine I started in 60/90 in a small Lortone barrel. I usually run at least a week, but when I opened that batch after the first week, about 30% of the rock material had disappeared.
For both, use lots of cushioning material - lots of it.
Just my 2 centavos. ;D
Tom
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Post by Toad on Sept 27, 2009 14:54:28 GMT -5
As beginners, you may want to set fluorite and sodalite aside and practice on some agates and jaspers first. Not that you can't be successful, but harder rocks are generally easier - even though they take longer. But as Tom said, fluorite and sodalite are really soft - do not mix (it's really important).
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swagle
off to a rocking start
Member since September 2009
Posts: 3
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Post by swagle on Oct 1, 2009 9:20:42 GMT -5
thanks for the help, everyone
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Oct 1, 2009 10:26:21 GMT -5
Sodalite is a pretty easy tumble- just be careful on the course grit- and add a step between med grit and prepolish(I do a 1 week run in 500 grit). Polish is pretty straight forward (I like Tin oxide- but have had great result using Aluminium Oxide as well) Matter of fact I can often sneak soadlite into my regular tumbles with good results. As for Fluorite- well I have tried everything but finally just gave up on it as it NEVER made it to the polish stage.
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