firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 1, 2009 10:54:36 GMT -5
I have finally progressed to the point of where I feel I have a batch of rocks ready for pre-polish. They've been in rough for 19 days, then 7 days in stage two. I'm making my judgment based solely upon how the rocks "look and feel". However, in referencing Hart's book, he talks about the importance of using some type of magnifier on the rocks to grade them, to distinguish whether all the scratch marks are uniform, and only when they're uniform, should they move on to pre-polish. I do have a magnifying glass, but haven't found that to be much help in viewing scratches. So my question here is do all of you use some type of magnifying implement to grade your rocks before moving on in the stages, or do you just use a look and feel test? If the rocks are not ready to move to the pre-polish, what are the consequences of doing so? Do you ruin the whole batch? Okay, three questions.  |
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Feb 1, 2009 11:59:59 GMT -5
a standard 10X jeweler's loupe should be at hand in any rock processing inspection point, although I don't use them that often with rotary tumbled batches, rather I go on naked eye appraisal, combined with finger feel of surface conditions.
It has been my experience that running 7+ day cycles usually allows each stage to do its thing pretty well, and if any rocks are not ready for the next stage they will make that obvious by revealed cracks or pits.
If you are diligent at the second stage, you usually won't have to cull too much later, as that first to second stage is a pretty good indicator of which rocks will make it the rest of the way.
The one thing, no two things- that might be an exception to that is rocks that might be slightly porous or too soft to run with the other material, stuff that is porous won't shine ever, so if something going into pre-polish seems less smooth than the rest of the batch, it probably should get set aside, and stones that are too soft will be obvious since they are getting a lot smaller- set them aside to run as a batch once you have enough.
Vibe cycles are enough shorter that I can see where a loupe inspection might be warranted, practice with the magnifier will soon reveal things you don't notice the first few times you use a loupe, so I would encourge that anyway, even though I use it more on the cabbing rig than on tumbles.
The consequences range from some rocks that have rough areas or pits even though the rest of them are shiny- to the worst case scenario where nothing takes a shine, most of us can live with the former but the latter situation can be very discouraging
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Post by cpdad on Feb 1, 2009 12:09:59 GMT -5
finger feel and looking for imperfections should be fine if you using a rotary.
you might want to use a loupe with a vibe though if you are first starting out......try not run softer stones with your batches...if you are mixing hardnesses.....you can usually take them put after rough and throw them in a bag untill you get enough for a complete load of the softer stuff.
if your happy with the look and feel after the second stage....you should be just fine moving on.....nothing much is gonna happen after the second stage assuming the barrell is loaded correctly and rocks arent banging into each other....hope that makes a little sense....kev.
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Post by cpdad on Feb 1, 2009 12:12:01 GMT -5
ya...what rallyrocks posted while i was typing ;D....kev.
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firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 1, 2009 20:59:37 GMT -5
rallyrocks and kev, thank you for your input, it's really appreciated. I should have clarified that these were rotary tumbled rocks. After reading your comments, I did re-examine the rocks sans a jeweler's loup which is not yet part of my inventory, and pulled some to send all the way back to a few days of rough. So your comments were very helpful and instructional. I'm still left with some real beauties to go to pre-polish as soon as I have a load.
I do have one more question regarding pellets. I have the plastic pellets and learned here that they're really not necessary in the rough grind. However, I'm now reaching the stages where they do become a necessity and wondered what the rule of thumb is in regard how much you add of the pellets? A tablespoon, 2, 3?
Bonnie
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Feb 2, 2009 0:27:01 GMT -5
I usually try to put in at least 2 or three tablespoons of pellets in any stage after course, but if a load is a little less than ideally full, I'll throw in more pellets to top off a load.
And I try to retain pellets and keep them to run in the same cycle next time, so I have a bin full and labelled for stage 2- another for stage 3 and since I usually run 5 stages I have some set aside for pre-polish and polish, although I usually try to use new ones for the polish cycle just to be on the safe side, but I'd expect no problems recycling polish pellets either.
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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 Feb 2, 2009 13:57:00 GMT -5
Pellets: I use about 1/2 cup for a 3 pound barrel
Magnifying Glass or Loupe to check for scratches: It's up to you. I'm sure most people don't do it unless they have trouble getting a good shine. It surely doesn't hurt to be extar cautious but is surely not necessary for most tumbling material
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firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 2, 2009 21:29:14 GMT -5
rallyrocks and chassroc, once again, thank you for taking the time to assist! All of you experienced tumblers are so generous with your time and experience and that is truly priceless.
I would assume that using the plastic pellets is a matter of preference as to how much as it seems rallyrocks, you do not use as much as chassroc, but you've given me a good range to work with and still be in the safe zone. Thank you also for the advice concerning reclaiming the pellets, this was something other forum members had taught me as well and it's valuable advice as the pellets are not extremely cheap.
I'm not sure how involved I'll become with checking the rocks for scratches as this is not something I'm doing for the art of perfection, but rather something I'm doing for my own enjoyment and no doubt, to gift friends and family. I would hope none of them would examine my rocks that closely. ;D I do think it's a good thing to learn, and in the future, I'll try to teach myself this, but for now I think I'll just go with what I find pretty or engaging in a rock.
Bonnie
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huffstuff
fully equipped rock polisher
Member since August 2007
Posts: 1,222
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Post by huffstuff on Feb 3, 2009 17:11:03 GMT -5
Hi Bonnie - this may be obvious, so I don't mean to offend.... I also let my rocks get fairly dry as part of my grading, especially between 1 and 2 (I understand that in this message you are talking about stage 2 going to stage 3). It's easier for me to see cracks that way. I'm pretty picky about what I move on to the next stage.
I'm glad you're enjoying this fabulous hobby!
Amy
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firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 4, 2009 18:24:02 GMT -5
Hi Amy, thank you for your advice and input! You know that whole batch of rocks ended up going back to Stage 2 for another week. I had put them in a container marked as ready for pre-polish, and of course they dried completely. The more I looked at them completely dry, the less happy I was with moving them on to pre-polish, so backwards they went! I'm curious though as to what happens in Stage 2 as opposed to Stage 1? From my very limited experience, it seems that the coarse stage does a great deal of shaping, smoothing, getting rid of pits and hard edges, etc. So when the batch is then moved to the finer grit of Stage 2, is the shaping and smoothing continued but to a lesser degree? I'm not sure I'm asking this correctly, but I've been very curious as to what exactly Stage 2 accomplishes, primarily because I've finally moved a batch into that stage. Bonnie |
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Feb 7, 2009 19:26:59 GMT -5
Bonnie: I rely solely on look/feel to judge when rocks go from coarse to medium and then from medium to pre-polish. I have observed that different aspects of the rock are visible wet vs. dry. I usually check them wet (just after rinsing) and save them in a jar until I have enough. Then, as I load the next stage, I check them again now that they have dried out. I inevitably send some back from this second check. I am really uptight about when rocks move on and have a lot of patience, so I always err toward the "send it back!" side of things.
I usually run many rounds of coarse (5-15) before I have enough to run medium. I usually run two loads of medium to end up with enough for one load that runs from pre-polish to the end.
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firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 8, 2009 19:52:26 GMT -5
ejs, thank you for your input on this. You know you have been the one who has been most instrumental for me in teaching me to send rocks back when there was any doubt. I know that's something you have said repeatedly to me in my time on the forum. Matter of fact, you had a "recipe" you posted recently which I think you used for black jasper (and the end result was gorgeous) and I actually wrote that recipe down and put it in my book to follow. Also the instruction to examine them wet, then dry, has been very helpful, as the dry stage, upon reexamination has prompted me to move lots of rocks back for another round of coarse. I've found that I'm not getting impatient any longer to move rocks on through the stages, but rather to wait until I feel they're truly ready. I think the reward of learning this kind of patience will present itself in the finished product. So at this point I have three barrels still working on coarse, and just about enough ready for second stage, and likely I'll examine those again before I actually commit. None of the rocks have yet moved to pre-polish, but rather have gone the other direction. I think they're being ready wasn't so much a reality as it was my being impatient to get to that finished rock.
Bonnie
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ejs
spending too much on rocks
Member since July 2008
Posts: 478
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Post by ejs on Feb 8, 2009 20:10:57 GMT -5
Bonnie: Thanks for your kind words. It sounds like you've got just the right attitude. I will sometimes let a borderline rock go from a coarse tumble to my "ready for medium" jar. But then at the end of the medium tumble, I insist that every rock be rounded and smooth. I feel like the end of medium is the last chance to pull any rocks out before a bad one can do some damage during pre-polish; a not-quite-ready-for-medium rock won't screw up a batch in medium grind. I hate the idea of one rogue rock screwing up a whole batch of polish! I think of it like this: the worst rock is the one that will determine the quality of the final polish. So I try to make that weakest link still be pretty darn strong. Keep going and keep us posted!
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Post by LCARS on Feb 9, 2009 1:19:03 GMT -5
One thing about using a loupe or magnifier to "grade" stones is that you have to know what your looking at/for but it is a good idea to do a running subjective/comparitive analysis of the macro surface texture of your various stones at different stages to acquire the necessary experience.  ;D I find a jewelers loupe especially usefull for inspecting my more "precious" batches about halfway through the polish stage to look for scratches caused by possible grit contamination. That way I can remove and basin rinse the stones and decant the slurry in a separate container while I scrub the lid and barrel. If you pour it back in the barrel slowly except for the last bit, any particles will stay behind and you can usually continue the polish stage (albeit for a bit longer) if you catch it in time. At the prepolish stage it can be tough to tell if any rogue grit particles are making deeper scratches until you get a feel for each type of stone and how it looks before/during/after each stage. |
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firstrune
starting to spend too much on rocks
Member since January 2009
Posts: 156
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Post by firstrune on Feb 10, 2009 14:09:12 GMT -5
LCARS, thank you for your input and suggestions. I do appreciate it. I have a jeweler's loupe on my list of future accessories to buy. At this point, I'm so new to this I'm staying with the tough guys, the agates and quartz and jasper mainly because I've learned here that these are the best rocks for a beginner to learn with. I hope in the future that I can move to the more challenging and more demanding rocks and I can see where I'll need to learn the art of grading to a higher degree.
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;D
