blackout5783
starting to spend too much on rocks
Member since November 2011
Posts: 248
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Post by blackout5783 on Nov 1, 2012 20:31:46 GMT -5
So I have approximately zero knowledge when it comes to cabbing. Previously my wife and I were grinding preforms on the edge of a tile saw and tumbling/polishing them in a Lot-O. So in an effort to get more control, we picked up a 2 wheel grinder and a spool polisher for a steal (about $60 together) at a mining museum "garage sale". (Side note: you can read about the motor fiasco in the Homemade Equipment section) The results have been less than stellar. At best, our cabs get a "golf ball" look to them. I'd say that they were getting an orange peel finish, but I thought that was the result of overheating? If you can imagine a golf ball with the raised parts polished, but the dimples dull, then you get the idea. I don't have a pic right now, but I'll try to remember to post one. Here's the process at the moment: 100 grit SiC wheel, 220 grit SiC wheel, then 325, 600, 1200, 8000, 15000, 50000 diamond grits on the spool polisher. So here's my thinking (ignore that burning smell): the problem is between the 220 SiC and the first stage of the spool polisher. So I wanted to replace the 220 wheel with an expando and SiC belts, but I have no idea what I'm doing. I was planning on 220, 400, and 600 SiC on the expando, but I wanted to try to polish on that as well. I saw that Covington sells a felt belt for a 6" expando, and thought that would work with CeO or SnO. Is a jump from 600 to polish too big? Should I get diamond belts for after the 600, but before the polish? Do the felt belts even work with a polishing compound on an expando? Like I said, I have no idea what I'm doing! Any help would be greatly appreciated!
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Post by roy on Nov 1, 2012 21:25:37 GMT -5
try a 100 grit diamond wheel on one side and a expando on the other so you can change the belts you will want to run them in water
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jason12x12
freely admits to licking rocks
Member since October 2011
Posts: 798
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Post by jason12x12 on Nov 1, 2012 21:38:55 GMT -5
i think a 600 grit sc is the hole in your process... a necessary step in my book
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Post by stardiamond on Nov 1, 2012 22:13:54 GMT -5
The only time I have any heat is when I am using the canvas pads for polishing and use silicone spray as a lubricant when necessary (not very often). Everything else involves a lot of water. Two geysers under a wheel on the genie and 3 geysers (not as good as the genie) under a wheel on my stardiamond machine.
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Tousled Owl
starting to spend too much on rocks
Member since August 2011
Posts: 129
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Post by Tousled Owl on Nov 1, 2012 23:25:43 GMT -5
I'm equally still dog-paddling in the kiddie pool around here, so bear that in mind and if any of the following is the result of reading too many Kingsley-North catalogs/inhaling too much Gem-Lube or something, somebody please help us both out.
I didn't see you say what material you are trying to work with. For some of the cabochon black belts on this board, they can probably take an emery board and a kitchen scrubby and make a beautiful shiny stone out of a clump of mud. I (and it sounds like you as well), not so much.
What I seem to be learning/figuring out as I go from 0.00 experience to 0.01 experience is that you have to start with the characteristics of your material and work **backwards** to come up with the best course of treatments to get you to your desired outcome.
Some materials are (in)famous for the Titleist outcome. I think the general idea is to work up the line and as you get to 1200 - 3000 - 8000 - 14000 you'll have to bail off the wheels/belts and go to some polishing agent on a pad/non-abrasive belt. Which agent on what kind of pad, as well as knowing when things will go downhill on the next higher wheel/belt is the magic. Everyone will have their absolutely 100% reliable combo, but I have a suspicion that at this stage, the minor variables about how you work a stone on your particular piece of gear start to have an impact. So their 100% method may be not quite so for your circumstances.
I think that assembling a "standard" process will give you a chance to prove that well-known 80/20 principle - you'll get good results 80 percent of the time, but the other 20% will suck - and no matter how you try to jigger the details of that specific process, the suckage will continue.
So, as I am doing my early experiments (aka "the ax-murder period" due to a tussle with some red tigereye), I'm finding that most jaspers and agates will turn out great using a sequence much like what you've described. Wandering off this safe path into obsidian, chrysocolla and its kin, tigereye, boulder opal.... did I mention tigereye? It's an interesting emotional trip to be standing there and have what just worked on THAT rock create a mess out of THIS rock. And occasions some lapis-blue language.
So, I'm hoping while I'm still in the green-belt stage to be able to at least group material by hardness, granularity, obsequiousness, something... into a relatively few number of categories and derive a relatively few number of branches off the main sequence of wheels and belts that ratchet the success rate up into the 90%'s.
Eventually (I hope), skill sets in and you can do with talent and experience what I am relying on toolage to help me with at present. Bear in mind that the variability of all the factors that sound like they should be constants is also in the middle of this. Your 400 belt may cut like a 400 because it is relatively unused, while someone else's 400 belt may give results on an absolute scale more like a 600 since it is nicely broken in.
Anyhow, I don't have very much data to offer on successful sequences/abrasives to offer just yet, but I'm starting to see that it's a least a finite number of variations to contend with, and this is good news.
I'm about to start posting pics (finally!!) and I am going to try to give something like a box score with each one to describe the process and the steps along the way for at least a while. I know looking (ogling!) at everyone else's pics has been very educational and gives me a standard to shoot for.
The other good news is that it's so darn much fun to experiment and figure this stuff out!
Enjoy, Jack
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Nov 1, 2012 23:52:07 GMT -5
It sounds like you have the Graves spool polisher. I also use it after I grind with a 100 and 220 wheel. But I do use an expanding drum sander with a minimum of 220 belt on it before going to 325 on the spool. Or with some stones like ocean jasper I find they do better wet on the expando than with diamond on the spool. It helps to save a lot of work getting scratches out to sand after grinding. And I learned the hard way to make sure not to use any ancient diamond paste on it. It seemed to leave a film on the cabs.
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blackout5783
starting to spend too much on rocks
Member since November 2011
Posts: 248
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Post by blackout5783 on Nov 2, 2012 9:33:07 GMT -5
I thought I was missing steps after the 220 wheel. Ideally I'd like to skip the spool polisher entirely for most stuff and finish on the expando. The last two things that we tried were larvikite and chalcedony. Would it work to go from maybe a 600 SiC belt to 800 diamond paste on the spool polisher, work up to 15000 or 50000, then finish with tin oxide on felt or leather? Thanks everyone for your help!
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Post by talkingstones on Nov 2, 2012 19:42:34 GMT -5
Ok...my for what it's worth. I started out on a two wheel Lortone combo unit with a 6"saw on one side, an expando and a sc 100 on the other. The sc is great for rough shaping and I still use it...except that it does enhance fractures because the vibration is hard. On the expando, I took it up to ...and js gems can correct me on this if I'm off... at least 14000. Sounds to me like on your 100-220 levels you arent getting the stones down to what they need to be. Even at 220, you want to remove all of the coarse scratcching and uneveness from the 100. Those low level grinds are where the majority of your work happens. Later stages...from like 600 up are your polishing and should be very light. My biggest problem has always been that I want to move up toooo fast and that sounds like what's happening here. Take your time up through 400. The rock isn't going to go anywhere. It's just a rock. You are the one rushing. From 600 on, make sure you aren't grinding in the same direction. Move that stone around. If it doesn't start to shine at the level you're on, go back a level or two and work the scratches out. Magnification really helps here. If it's still not working for you...ASK MORE QUESTIONS AND POST PHOTOS!!! :-) You're gonna get this and when you do...it's really gonna be cool!
Enjoy!
Cathy
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,623
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Post by QuailRiver on Nov 2, 2012 23:49:45 GMT -5
Welcome to the Hobby! The spool polishers are okay for some stones but they do tend to generate heat which can damage many materials. But you should not smell burning smells at any stage of grinding or sanding. If you do then you are not using adequate coolant. If using a SC 100 grit grinding wheel and then 220 grit SC grinding wheel you can follow with a 400 grit SC sanding belt/disc followed by a 600 grit SC sanding belt/disc. Then for pre-polish you can use a well worn 600 grit SC belt/disc or an 800 grit SC belt/disc. Then go to polish. I like Cerium Oxide on Felt for high silica materials and Aluminum Oxide on leather for most other materials. Or you can follow the 220 grit SC grinding wheel with 600 grit diamond belt/disc, then 1,200 grit diamond belt/disc, and then (optional) 3,000 grit diamond belt/disc. When using SC grinding wheels and sanding belts/discs, to avoid contamination, it's important to wash the stone and dop stick well with soapy water after each stage to remove loose SC particles before going to the next stage. And when using diamond bort it's also important to clean the stone well between stages. I used to use cigarette lighter fluid (Naptha) to clean off the diamond bort between stages. If you don't do this you risk contamination of your wheels/belts/discs. And once a canvas resin belts/disc, wooden spool polisher, or polishing wheel gets contaminated it's very difficult to ever get them uncontaminated. When using diamond grinding wheels, soft flex diamond wheels, or factory charged diamond belts/discs, contamination is not as likely to occur as with SC and diamond bort products. For diamond bort charged belts/discs I used to use Silicon Spray for a lubricant - be careful not to breath the spray. For all other diamond products. SC products, and for oxide polishing pads I use lots of water for coolant. When using SC products it's a good idea to not recycle your coolant water and always fresh clean water to avoid contamination. It's very important to ALWAYS use clean water for coolant on your felt and leather polishing pads in order to avoid contamination. Hope this helps.
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QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,623
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Post by QuailRiver on Nov 2, 2012 23:59:53 GMT -5
I just thought of one other thing I might should mention since you're using SC grinding wheels. When you are finished grinding you should turn off the water coolant supply and leave the motor running until the SC grinning wheels spin dry. If you don't spin the wheels dry the water that has been absorbed by the wheel will settle on the downward side of the wheel and will cause the wheel to be unbalance when the motor is turned back on. In rare cases this has caused SC wheel to fly apart. But at a minimum this can cause a SC wheel to start developing a bad wear pattern similar to how an out of balance automobile tire will.
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Post by Tonyterner on Nov 3, 2012 7:30:18 GMT -5
You've got lots of good advice. Remember the spool polisher you have is for polishing. In my opinion 325 and 600 are not polishing stages. I tried SIC wheels and belts when I first started out to save some money but it cost me a lot of hair. It takes a heck of a lot longer to grind on SIC and I was never happy with the belts. They wore out after only a few cabs. The leap to diamond made a huge difference in my cabs and made me so much happier.
I'm assuming you got your grinder at the Franklin show. My wife picked up a Genie there 2 years ago for only $150. You can get some steals up there.
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