ivan
starting to spend too much on rocks
Member since March 2014
Posts: 165
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Post by ivan on Feb 20, 2018 14:15:02 GMT -5
This is all kind of fuzzy to me! But the thought has occurred to me concerning the preparation of gem materials in order to obtain a fairly decent polished finished cab upon completion. After pondering on this I decided to present this to our RTH Forum. That is, to people that are more knowledgeable in this matter and have been successful in accomplishing this?
So any information, suggestions, direction & assistance would be appreciated. Using Vibratory or Rotary, if that would make a difference. Hope this helps? Thank you for taking the time to discuss this and for sharing your thoughts & ideas. IV
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Post by parfive on Feb 20, 2018 14:22:08 GMT -5
Fuzzy being the key word, eh?
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Post by Jugglerguy on Feb 20, 2018 14:41:10 GMT -5
Drummond Island Rocks should be able to help you. I know that you should do it in a vibe with lots of ceramics. Chuck can help you with the specifics.
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minerken
Cave Dweller
Member since August 2013
Posts: 466
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Post by minerken on Feb 20, 2018 15:57:20 GMT -5
I have been tumble polishing cabs for several years now. I think the preferred method is using the vib although there are those who can probably get great results using a rotary. The reasons that I prefer the vib is for a few reasons 1. the vibe is much more aggressive and reduces the time necessary to get a high quality to even superior quality polish depending on your expertise and that comes with time. Although the vib is more aggressive it doesn't tend to change the shape much mostly due to not using very coarse grits most vib barrels are not designed to handle anything coarser than 120 grit but there are exceptions. Although they don't affect the shape much there is a rounding on sharp edges and by some this is not acceptable. Technically a cab has a convex surface on a least one of the two faces so this so this dictates that the shape has to be pre-formed (ground) first. usually through at least 120 and probably a minimum or 220 grit. The use of ceramic media is kind of a personal preference and generally depends on how far you take the pre-form here again time and experience and what you want to accomplish dictate what and when to do it. In all fairness you can probably achieve as good or better a product using the traditional cabbing methods i.e. wheels. So is it worth it
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Post by Drummond Island Rocks on Feb 20, 2018 18:03:02 GMT -5
1. I only tumble cabs in the lot-o vibe tumbler and run them through 120/220, 500, 1000 and then sub-micron grade A/O polish 2. I do not tumble any cabs that contain mixed hardness minerals. Those are better left to the cabbing wheels. I mostly only tumble solid agates and jaspers. 3. 80 percent of the load will be a mix of small and large angle cut ceramics. This is necessary due to the large flat areas of cabs. 4. I often go back and clean up the girdle on the cab wheels to get the sharp I edge I like back. This means hitting all the girdles with 220 hard wheel and then 280-3000 soft wheels. I had a couple of really good pictures in the thread below to describe the girdle clean up but photobucket stole them. Might still be good reading. forum.rocktumblinghobby.com/thread/68846/tumbled-cab-girdle-cleanupChuck
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Post by Drummond Island Rocks on Feb 20, 2018 18:44:45 GMT -5
This photo shows why the load need to have such a high content of ceramic filler. Notice the edges are nice and shiny but the flat is still dull. I keep this picture around just to explain this situation. These were tumbled in the lot-o. Notice they are nice solid materials. The cabs shown above had not had the girdles re-worked yet. After re-working the girdles I do not think they could be any better if they were fully cabbed on wheels. Chuck
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Feb 20, 2018 19:54:47 GMT -5
The cabs shown above had not had the girdles re-worked yet. After re-working the girdles I do not think they could be any better if they were fully cabbed on wheels. I agree. Fantastic shine!
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ivan
starting to spend too much on rocks
Member since March 2014
Posts: 165
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Post by ivan on Feb 20, 2018 20:45:48 GMT -5
Fuzzy being the key word, eh? Fuzzy or Foggiest seems to work!
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ivan
starting to spend too much on rocks
Member since March 2014
Posts: 165
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Post by ivan on Feb 20, 2018 21:09:23 GMT -5
1. I only tumble cabs in the lot-o vibe tumbler and run them through 120/220, 500, 1000 and then sub-micron grade A/O polish 2. I do not tumble any cabs that contain mixed hardness minerals. Those are better left to the cabbing wheels. I mostly only tumble solid agates and jaspers. 3. 80 percent of the load will be a mix of small and large angle cut ceramics. This is necessary due to the large flat areas of cabs. 4. I often go back and clean up the girdle on the cab wheels to get the sharp I edge I like back. This means hitting all the girdles with 220 hard wheel and then 280-3000 soft wheels. I had a couple of really good pictures in the thread below to describe the girdle clean up but photobucket stole them. Might still be good reading. forum.rocktumblinghobby.com/thread/68846/tumbled-cab-girdle-cleanupChuck Do you start with the rough outline cut out and put the rough batch into the tumbler or do you preform or shape your cab first and then run through the steps as outlined. About how long would you say it should take in each cycle. You're right I did find the link but photos not present. Is it possible to maintain an accurate finished cab ... such as 18 x 13 ... or close? The finished cabs posted are outstanding & very nicely done. Excellent symmetry & polish. Thank you for sharing your work & procedure. IV ]
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ivan
starting to spend too much on rocks
Member since March 2014
Posts: 165
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Post by ivan on Feb 20, 2018 21:25:01 GMT -5
I have been tumble polishing cabs for several years now. I think the preferred method is using the vib although there are those who can probably get great results using a rotary. The reasons that I prefer the vib is for a few reasons 1. the vibe is much more aggressive and reduces the time necessary to get a high quality to even superior quality polish depending on your expertise and that comes with time. Although the vib is more aggressive it doesn't tend to change the shape much mostly due to not using very coarse grits most vib barrels are not designed to handle anything coarser than 120 grit but there are exceptions. Although they don't affect the shape much there is a rounding on sharp edges and by some this is not acceptable. Technically a cab has a convex surface on a least one of the two faces so this so this dictates that the shape has to be pre-formed (ground) first. usually through at least 120 and probably a minimum or 220 grit. The use of ceramic media is kind of a personal preference and generally depends on how far you take the pre-form here again time and experience and what you want to accomplish dictate what and when to do it. In all fairness you can probably achieve as good or better a product using the traditional cabbing methods i.e. wheels. So is it worth it Very good post .. minerken. At some point I may get enough ambition to do up a few preforms and see what happens. Not sure if it is necessary but doing it this way sort of takes care of front & back of cabs at the same time. Thanks for taking the time to share your expertise. IV USAF 62-66
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ivan
starting to spend too much on rocks
Member since March 2014
Posts: 165
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Post by ivan on Feb 20, 2018 21:37:20 GMT -5
This photo shows why the load need to have such a high content of ceramic filler. Notice the edges are nice and shiny but the flat is still dull. I keep this picture around just to explain this situation. These were tumbled in the lot-o. Notice they are nice solid materials. The cabs shown above had not had the girdles re-worked yet. After re-working the girdles I do not think they could be any better if they were fully cabbed on wheels. Chuck By the example I see what you mean by the quantity of ceramic media or filler that must be needed. The cabs are, exceptional & thanks again for the information. I don't expect I will be posting any of my finished cabs soon. IV
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Post by Drummond Island Rocks on Feb 21, 2018 7:17:37 GMT -5
1. I only tumble cabs in the lot-o vibe tumbler and run them through 120/220, 500, 1000 and then sub-micron grade A/O polish 2. I do not tumble any cabs that contain mixed hardness minerals. Those are better left to the cabbing wheels. I mostly only tumble solid agates and jaspers. 3. 80 percent of the load will be a mix of small and large angle cut ceramics. This is necessary due to the large flat areas of cabs. 4. I often go back and clean up the girdle on the cab wheels to get the sharp I edge I like back. This means hitting all the girdles with 220 hard wheel and then 280-3000 soft wheels. I had a couple of really good pictures in the thread below to describe the girdle clean up but photobucket stole them. Might still be good reading. forum.rocktumblinghobby.com/thread/68846/tumbled-cab-girdle-cleanupChuck Do you start with the rough outline cut out and put the rough batch into the tumbler or do you preform or shape your cab first and then run through the steps as outlined. About how long would you say it should take in each cycle. You're right I did find the link but photos not present. Is it possible to maintain an accurate finished cab ... such as 18 x 13 ... or close? The finished cabs posted are outstanding & very nicely done. Excellent symmetry & polish. Thank you for sharing your work & procedure. IV ] I do not use any prefabricated settings so holding dimensions has never been a concern for me. I do not think you will be able to end up with a calibrated cab with this method. My reason for tumbling cabs is not to save time it is to end up with a better cab. Certain materials always seem to be a hassle to get finished without any scratches so those are my targets. Materials like Brazilian agate and Montana agates are prime examples. The cabs I tumble are fully shaped and domed on the cab machine with 80 and 220 hard diamond wheels then lightly cleaned up on the soft 280 wheel before going into the vibe tumbler. Once in the vibe tumbler they spend about 48 hrs in each stage. Chuck
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,685
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Post by Fossilman on Feb 21, 2018 11:31:28 GMT -5
I use the rotary for my cabs...They do get some what smaller, but not much (depending on material) I start with the finished preform cuts, load up the rotary to max (fill),also with ceramic pellets...I do start with the 90 grit, to get the edges worked down.. Than go through the 220 stage, 600 stage, prepolish, than polish stages... You will get a 99% return, a few break (Can't be helped)a hidden fracture, etc... They come out so nice.....Thumbs up and good luck..
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minerken
Cave Dweller
Member since August 2013
Posts: 466
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Post by minerken on Feb 21, 2018 13:08:41 GMT -5
I use basically the same method as Chuck @drummond Island Rocks does but take mine to 600 on the wheels my reasoning behind this is that I figure my saw leaves about a 400 finish. I then start tumbling at 600 grit and then go to at least 1000 this is all a work in progress. I use about the same ratio of ceramic to stone as Chuck does and normally wait until I have a batch of about 40 before starting. Here's a typical batch and a single or two showing how pointy you can get IMG_2697.JPG Modified on March 9, 2015
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Post by Jugglerguy on Feb 21, 2018 14:23:12 GMT -5
Drummond Island Rocks, I couldn't remember if you ran your cabs for a full 48 hours in 120/220. I'm a little surprised by that. I thought you would either start with 500 or run the 120/220 batch overnight before adding your cabs. I guess you'd still have to clean the girdles either way, but the rounding to the edges would be less severe if you started with a finer grit. I see that Ken does that.
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Post by Drummond Island Rocks on Feb 21, 2018 14:47:20 GMT -5
Drummond Island Rocks, I couldn't remember if you ran your cabs for a full 48 hours in 120/220. I'm a little surprised by that. I thought you would either start with 500 or run the 120/220 batch overnight before adding your cabs. I guess you'd still have to clean the girdles either way, but the rounding to the edges would be less severe if you started with a finer grit. I see that Ken does that. Yeah that is a tough one to describe. If I am tumbling preforms with no dome I run them the full 48 hrs because I want the edges to round as much as possible. If I am running domed and pre-grooved cabs I want all of the edges including the groove to be slightly rounded so those I may toss in after the grit has been running for 12-24 hours. If I am running true cabochons I will run my grit for 24-36 hours prior to tossing them in to lessen the rounding. Of course all of that is based on my experiences running 120/220 grit in a lot-o. Straight 220 grit in a different tumbler may change all of that. Chuck
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Post by rockjunquie on Feb 21, 2018 19:19:22 GMT -5
I doubt I'll be taking up tumbling anytime soon, but this is quite interesting. I used to have to buy cabs and I got a few that NOW I know were tumble polished. I do absolutely LOVE the vibe polish, but I wonder for those of you who sell- do you disclose that they are machine polished and not hand polished? I think it should make a difference in price. Or, am I wrong? I take nearly all of mine to 100,000 grit now and I approach a vibe polish, but I doubt I could do one as well every time.
I have had the pleasure of owning one of Chuck's vibe polished cabs and they are perfect! Wow.
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Post by Jugglerguy on Feb 21, 2018 20:03:23 GMT -5
I doubt I'll be taking up tumbling anytime soon, but this is quite interesting. I used to have to buy cabs and I got a few that NOW I know were tumble polished. I do absolutely LOVE the vibe polish, but I wonder for those of you who sell- do you disclose that they are machine polished and not hand polished? I think it should make a difference in price. Or, am I wrong? I take nearly all of mine to 100,000 grit now and I approach a vibe polish, but I doubt I could do one as well every time. I have had the pleasure of owning one of Chuck's vibe polished cabs and they are perfect! Wow. If they have a good polish and have no downsides, why does it matter how the polish was achieved? They’re all done with machines, right? I say use the best machine for the job. I like that Chuck takes the extra step to clean up the girdle so there are nice crisp edges. Maybe if all the edges were rounded off and that didn’t show up well in pictures, then it should be disclosed, but otherwise I don’t see a problem.
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Post by rockjunquie on Feb 21, 2018 20:24:38 GMT -5
I don't think there is a problem. I have heard the argument that a tumbled cab is not hand cut and should not cost as much. I was wondering what y'all thought about that. Personally, I have paid top dollar for cabs that turned out to be vibe polished and I didn't really care. If it's a great looking cab, then it's a great looking cab. I would even argue that it isn't necessary to clean up a girdle. The ones I have seen are still perfectly usable. But, there is a debate. I saw a guy on ebay, I don't know if he is still there, but he had cabs that were hand cut and he had cabs that he advertised as tumbled cabs. He charged less for tumbled stones. I thought it was honest of him to state they were tumbled. Most don't. Being tumbled would not keep me from buying them.
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Post by HankRocks on Feb 21, 2018 20:37:23 GMT -5
One thing about Cabs in the tumbler or in my case, pre-forms, it goes on the basis of survival of the fittest. In every batch I run there are those that break and there are those that deform due to a slightly softer portion. Any that have Quartz exposed along one of the edges is especially vulnerable to deformation. A good number of the West Texas Plumes and Bouquet can be in quartz within the agate biscuit. Not sure that these would work any better cabbed by hand.
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