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Post by knave on Sept 5, 2020 12:23:21 GMT -5
I think it’s cool that it went 3 years in rough, and adds to the story of the stone, and the value. The purist in me appreciates tumble only.
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Post by Bob on Sept 8, 2020 11:03:27 GMT -5
The first 3 years, I just put rocks in the barrels right from the field, no matter their shape or problems. I love the random and weird shapes of the finished polished rocks that result. Now and then, I would cleave off a weird projection, but not very often. Then I got a rock hammer and some chisels. I would still put everything through that first week of rough grind to get off the rind and see what I had, then I would toss those that needed something broken off into a pile and would do that now and then. It obviously saved months of grinding and grit and money on some rocks.
Then a year ago I got a used cheap tile saw after failing to be able to cleave ANYTHING from a piece of BC nephrite. It's messy and the RPMs are too high for a rock saw, but if I feed slowly and carefully it works. On a very large rock, I can make a groove from which to cleave. Using the messy tile saw isn't much fun for me and I dread getting it out and doing it. But since doing it I've noticed that rough grind produces much more rocks more quickly read for next grit level. However, I highly dislike the perfectly flat surface on a rock from a saw pass that ends up on a polished rock. So I look forward to when I finally get that 8" wet arbor grinder set up.
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Post by Mel on Sept 9, 2020 8:46:04 GMT -5
I didn't give it any special treatment at all. It was just another rock in the barrel.
.... look forward to when I finally get that 8" wet arbor grinder set up.Isn't that a Pink Floyd song? I need to copy your wisdom and make notes; my brain & "winging it" are a bad combo.... I'm curious about your arbor-grinder. Care to share some details? I'm looking at getting a trim saw/arbor combo specifically for avoiding the long, long grind times on some of the stones I pick up, and for trimming down the smaller stuff since I'd like to get into more expensive stones down the line.
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Post by Bob on Sept 9, 2020 9:48:36 GMT -5
Mel, I guess I'm not only one using a simple first name. I was actually listening to several track from The Wall last weekend! A wet arbor is a arbor stand with a shaft turning in it that has a water system to keep the grinding wheel wet. There are many types. Mine is like this, but this photo doesn't show the grinding wheels mounted or the drip water hoses that keep the wheel wet. The belt to the motor can go out the back or down below the base underneath. I have already bought the rough wheel, which I think is 60 grit and am only going to run that for the time being. I might mount a finer grit on the other side eventually. I just haven't used it yet because I haven't finished the water and hoses setup. Seeing those posts about a tuck point blade has me thinking I might even try that on one side.
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SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
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Post by SirRoxalot on Nov 17, 2020 20:57:10 GMT -5
That agate is mind blowing. Most big rocks like that are polished by hand, not tumbled. You need to make a mega-grinder, or use a cup grinder on an angle grinder, and you need to make a big tumbler out of a propane tank, at minimum. An hour or two of pre-grinding, and a big barrel doing 90 RPM, and you’ll cut your tumbling time by... 90%
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Post by Bob on Nov 18, 2020 15:16:54 GMT -5
Would spoil the fun a bit, but would sure save a lot of grit!
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cman60
off to a rocking start
Member since September 2019
Posts: 13
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Post by cman60 on Jan 1, 2021 13:32:00 GMT -5
Talk about giving me inspiration to try / have the patience to tumble big rocks. thanks for all the knowledge.
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