jack360
off to a rocking start
Member since May 2007
Posts: 18
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Post by jack360 on Jun 5, 2007 19:57:12 GMT -5
Got some large mine rough. Not expecting wealth or fortune.
My dad has a grinder. I wanted to grind away some of the matrix before tumbling for obvious reasons. Anyway when I got down close to the emerald, I noticed that the rock almost emitted a kind of light from within'. (Heat) Anyway, when I stopped grinding to my dismay the side I grinded was near flat (what I wanted) but it was all WHITE.
What used to be green was now a smokey white color. I made some assumptions. The emerald got too hot. Correct? Thus changing the color of the stone internally somehow? Correct?
If so, why does this happen.......and is there a way to avoid it?
Am I wasting my time with this post?
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Post by joe on Jun 5, 2007 20:35:43 GMT -5
I've never worked emeralds so I don't know, but is it possible the heat "crazed" the stone? Look closely and see if the white isn't a lot of tiny cracks in the stone. The entire surface may be crazed, giving it a white look. That needs to be ground away. Use a lot of water flowing over the stone while grinding and maybe use a finer wheel. what kind of setup did you use to grind it?
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jack360
off to a rocking start
Member since May 2007
Posts: 18
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Post by jack360 on Jun 5, 2007 21:28:10 GMT -5
Yeah, you're right I think,..........cause I took the same emerald and have had it tumbling in 90 grit for 72 hrs now and the white is gone.
However, I did loose the flat "shape" I was going for. Now it's just round. Lol.
Ok setup is your standard store bought sears craftsman grinder.
It has a rough grinder on the left side, a finer grinder on the right side.
It was meant for tools I think. Sharpening blades, whatnot.
Not emeralds.
So tell me, what kind of grinder should I be looking for? (Noob here)
Thanks
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Deleted
Deleted Member
Member since January 1970
Posts: 0
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Post by Deleted on Jun 6, 2007 0:59:30 GMT -5
I hate when you have a good rock and something goes wrong and destroys it. A few months ago I found a nice rock with some nice big crystals on the top and I was walking outside to take a look at it and tripped and slammed it on the ground and the rock didn't get a scratch, but all the crystals had been smashed off.
(I was annoyed because that wasn't the first time I have done this)
Nathaniel
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Post by sandsman1 on Jun 6, 2007 3:13:00 GMT -5
i would think any wet grinder would be ok with the right wheels on it but you need a water drip to cool the stone wile your workin it --- you can make a wet grinder i have seen some good ones made here by members or you can buy a bare bones one like a lortone or something like that and find a deal on a motor and wheels i made my first one from a lorton 2 wheel 8 inch for around 200.00 with carbide wheels and it worked fine till i got a taste of the diamond wheels and i wouldent go back now -- but i bought the grinder on ebay new for 100.00 and watched ebay some more for wheels and a motor i think i was gettin wheels for like 15 to 20 bucks apiece when i was lucky and bought an expandable drum and belts to do from 220 to 1200 to finish cabs and i found 1/3 horse motors new from a guy for 18.00 apiece then i set up a water drip for it with a five gallon bucket
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Post by joe on Jun 6, 2007 21:12:26 GMT -5
Oooh yeah, using that grinder dry would overheat a stone. It has Aluminum Oxide wheels. They can work on stone but are NOT the ideal! Sands has it right (Of course he does, I learned from him and many others here!!  ) Silica Carbide wheels are much superior. And a water system, whether a drip or a bubbler, is very helpful to keep the dust under control and keep the stone cool. What kind of grinder you want is gonna be determined by your budget. If you have 1800 bucks to spend look up the Diamond Pacific Genie. If not there are many other options. I use a Lortone arbor. You can make your own stuff if you are good with tools. |
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RockyBlue
fully equipped rock polisher
Go U.K.
Member since June 2006
Posts: 1,719
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Post by RockyBlue on Jun 7, 2007 1:28:05 GMT -5
Hey Jack!
I had the same problem when i first got my grinder i used the wheels that came with it to grind a bunch of blue lace agate and i ruined all of them because i got them too hot,since then i got a green
grinding stone 100 grit,but the 100 stone is a little soft,it really grinds fast,but they don`t last too long
so the members suggested i use a 250 grit which is a harder stone, it does a much better job finishing stones before tumbling or what ever..................Rocky
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Post by rocklicker on Jun 7, 2007 2:40:31 GMT -5
I found jade to do that also, but I think I was useing too rough of a wheel because I over-irrigate my wheels.
As far as grinders go, it really depends on your budget and how much space you have. I use a Lortone arbor as Joe talks about. I like it and it's good and sturdy. I find that I am changing belts because it's a 2-station machine. The more wheels on it at one time the better, but then it starts getting big and then expensive.
Steve
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) Silica Carbide wheels are much superior. And a water system, whether a drip or a bubbler, is very helpful to keep the dust under control and keep the stone cool.
