StoneCrazy
spending too much on rocks
Stone Crazy
Member since July 2011
Posts: 331
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Post by StoneCrazy on Aug 17, 2011 8:58:47 GMT -5
It doesn't take much anymore to get me confused, but this should not be that confusing. Ok My rocks went in med grit for two weeks . I recharged the second week. Then gave them a bath with ivory for a couple hrs. I layed them out and they dried. I couldn't believe that they were shinny. Not glossy but maybe satin kinda shine. So the next thing is prepolish right or fine grit. They started fine grit on the 13th. today they are dull cant even get a shine with rubbing them with polish? does this sound right? I started this new batch because I thought I didn't leave the first ones in long enough with the med. grit. They came out dull after two weeks with the fine grit.
Well I hope I didn't confuse you too much
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Aug 17, 2011 9:18:44 GMT -5
You didn't say what you are tumbling. Softer rocks (like obsidian) often behave this way. Your med grit broke down enough so that it acted like a prepolish, so when you put in the fine grit it actually roughed up the rock. Also if you lost too much volume the rocks crash into each other. The solution may be to add bulk, plastic pellets or similar rocks already brought to the same stage. Also run the fine grit longer so it can break down to at least the same state as your med grit.
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StoneCrazy
spending too much on rocks
Stone Crazy
Member since July 2011
Posts: 331
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Post by StoneCrazy on Aug 17, 2011 9:29:30 GMT -5
I'm tumbling rocks from Cape May Beach. These are mainly quartz with a few other odds and ends in there.
Thanks Steve. I will keep them a tumbling.
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Steve
has rocks in the head
Member since June 2005
Posts: 506
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Post by Steve on Aug 17, 2011 9:48:53 GMT -5
The few other odds and ends could also be the problem. If these are harder than the quartz (agates or jasper) then they may keep the quartz from polishing. Typically, only the hardest material in a mixed run will polish. You may need to take out any harder material.
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StoneCrazy
spending too much on rocks
Stone Crazy
Member since July 2011
Posts: 331
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Post by StoneCrazy on Aug 17, 2011 9:55:37 GMT -5
Yes you are right. That is what I have in with them, but aren't they the same hardness.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Aug 17, 2011 13:01:35 GMT -5
Boy, I don't understand why folks have such a problem tumbling quartz materials. I do pretty much nothing but mixed batches and often include crystalline quartz, agate and jasper in the same mix with no problem. Only reason I can see for rocks getting rougher after they are already shiny is batch contamination where coarser grit has somehow gotten into he load or too much knocking together which can frost over the stone with little micro fractures. Otherwise as you've seen in your long runs in medium grit, the grit simply breaks down with time and eventually becomes prepolish etc. I use plastic beads in every batch after coarse grind to cushion the load and prevent too much knocking together and clean very well between batches plus use a dedicated barrel for prepolish and polish so as not to contaminate the pre and polish barrels with grit.
My final formula for quartz family gems which I repeat time after time is:
60/90 till the rocks are smooth and rounded with weekly wash offs and recharges ( could go as long as six to eight weeks)
110/220 fine grind one week (with plastic pellets) ( two days if I use the vibe) Tripoli prepolish five days (with plastic pellets as filler) vibe (or rotary seven days)
Rockshed aluminum oxide 5 days (with plastic pellets as filler) vibe (or rotary seven days)
Dreft burnish one day
This is actually probably longer runs in prepolish and polish than I need but I'm not impatient so I just keep the runs a little longer. Mirror polish every time. It ain't rocket science but you must be consistent and keep everything clean and filled to proper levels and it always does best with a good mix of sizes. Actually, the more small stones you have the better the polish you'll get on slabs and larger stones......Mel
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StoneCrazy
spending too much on rocks
Stone Crazy
Member since July 2011
Posts: 331
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Post by StoneCrazy on Aug 17, 2011 14:42:09 GMT -5
Thanks Mel Good info
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unclestu
Cave Dweller
WINNER OF THE FIRST RTH KILLER CAB CONTEST UNCLESTU'S AGUA NUEVA AGATE
Member since April 2011
Posts: 2,298
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Post by unclestu on Aug 17, 2011 15:45:34 GMT -5
Boy, I don't understand why folks have such a problem tumbling quartz materials. I do pretty much nothing but mixed batches and often include crystalline quartz, agate and jasper in the same mix with no problem. Only reason I can see for rocks getting rougher after they are already shiny is batch contamination where coarser grit has somehow gotten into he load or too much knocking together which can frost over the stone with little micro fractures. Otherwise as you've seen in your long runs in medium grit, the grit simply breaks down with time and eventually becomes prepolish etc. I use plastic beads in every batch after coarse grind to cushion the load and prevent too much knocking together and clean very well between batches plus use a dedicated barrel for prepolish and polish so as not to contaminate the pre and polish barrels with grit. My final formula for quartz family gems which I repeat time after time is: 60/90 till the rocks are smooth and rounded with weekly wash offs and recharges ( could go as long as six to eight weeks) 110/220 fine grind one week (with plastic pellets) ( two days if I use the vibe) Tripoli prepolish five days (with plastic pellets as filler) vibe (or rotary seven days) Rockshed aluminum oxide 5 days (with plastic pellets as filler) vibe (or rotary seven days) Dreft burnish one day This is actually probably longer runs in prepolish and polish than I need but I'm not impatient so I just keep the runs a little longer. Mirror polish every time. It ain't rocket science but you must be consistent and keep everything clean and filled to proper levels and it always does best with a good mix of sizes. Actually, the more small stones you have the better the polish you'll get on slabs and larger stones......Mel Thanks Mel. I have not started tumbling yet but itiis only a matter of time. I book marked this for the future. Stu
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Post by tanyafrench on Aug 17, 2011 17:20:25 GMT -5
Chaplady, you are receiving information from the pros. I also have mixed quartz with agates and jaspers and have had some great results. I have always used the rotary tumbler until now and I have a load in the vibe tumbler which I am taking out on Friday. Since I check this several times a day, so far I am very pleased and tempted to take them out now but they've only been in since Monday. Anyway point is that you follow what Mel is telling you and you should begin to get a great batch, nice, smooth and shiny. Good luck and don't get discouraged.
Tanya
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Post by ColtChainmailJewelryDesigns on Aug 17, 2011 20:04:04 GMT -5
I bookmarked this too, thanks mel!
Steve, You said softer stones like obsidian.... Isn't Obsidian a hardness of 7 or something? =P
~Colt
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Aug 17, 2011 20:18:44 GMT -5
Colt: Nope, obsidian is mohs 5- 5 1.5 while agate and jasper usually run a bit harder ( mohs 6-7) depending on inclusions etc.. Plus, since it has no crystal or fibrous structure, obsidian is not tough but rather brittle. Gets microfractures from being knocked around really easily so best tumbled alone. I did though, do a batch of apache tears along with feldspar and they all polished well enough....Mel
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Aug 20, 2011 16:56:17 GMT -5
Colt: Nope, obsidian is mohs 5- 5 1.5 while agate and jasper usually run a bit harder ( mohs 6-7) depending on inclusions etc.. Plus, since it has no crystal or fibrous structure, obsidian is not tough but rather brittle. Gets microfractures from being knocked around really easily so best tumbled alone. I did though, do a batch of apache tears along with feldspar and they all polished well enough....Mel But she's tumbling 'mostly quartz' with agate and jasper. Her question pertains to this mix. Not obsidian. So, more concisely, aren't quartz, jasper and agate all the same hardness? This leading to the success mentioned above?
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Aug 20, 2011 17:45:27 GMT -5
shotgunner: I was responding to Colt's question about obsidian . And yes, quartz agate and jasper are all of similar hardness depending on inclusions, though crystalline quartz is a bit more brittle and less tough than things like massive quartz and quartzite that you would find a lot of in beach gravel. Crystalline quartz as a result, can sometimes be a bit chippy in a mix with large agate or jasper stones....Mel
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chassroc
Cave Dweller
Rocks are abundant when you have rocktumblinghobby pals
Member since January 2005
Posts: 3,586
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Post by chassroc on Aug 22, 2011 8:11:38 GMT -5
Chaplady, I have tumbled "Cape May Diamonds" before with great success.
Heed the advice you've seen in this thread.
You did the right thing, ignoring coarse and starting with medium grit for these ocean tunmbled rocks.... and use filler(plastic or ceramic) with any quartz
When in doubt, don't mix rocks.
Charlie
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