shadyatbest
off to a rocking start
Member since November 2016
Posts: 23
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Post by shadyatbest on Jul 28, 2018 17:22:12 GMT -5
I am a total noob to the whole rock tumbling game. I recently picked up some large pieces of jasper with the intention of tumbling it. I was breaking up a large cantaloupe sized rock with a hammer and this question came up. I am sure wasting a lot of material by smashing it with a hammer. I end up with all different sized rough. Then i end up destroying the bigger pieces when trying to make them a tad smaller.
So what do you guys do with your oversized rough? Do you try to give it a basic shape before tumbling? I have a tile saw and could trim these up a little.
Thanks Travis
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Post by grumpybill on Jul 28, 2018 17:59:53 GMT -5
Just my opinion, but I'd use the tile saw to trim them up. Saves a lot of time during the course tumble stage.
You can also use the tile saw to break up big rocks without generating so much waste: Saw a notch about 1/2" deep part way around the rock, then use a stone wedge (or blunt quickly-tapered chisel) with fairly light taps with a 2 or 3 lb mash hammer to "wedge" the rock into 2 pieces. Don't let the wedge "bottom out". You want as much of the force pushing outward as possible.
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Post by aDave on Jul 28, 2018 19:49:40 GMT -5
While some folks are successful doing so and don't mind some waste from hammering, I typically will size down rocks on a tile saw. It's more precise and tends to eliminate excess waste. Besides, pounding rocks can also create additional fractures which can impact results down the road. The "negative" to using a saw is that some feel that a finished stone looks "less natural" in shape. Not a big deal for me, as they are polished smooth in the end.
I typically don't pre-shape too much, but I do have some material that I need to trim/grind, as they have some cracks, pits, and/or other"bad" spots that won't tumble out in coarse - they were pulled out of coarse after starting. The only real time that I take to pre-shape is when I'm sizing down, and I can kill two birds with one stone.
I haven't had to use Bill's technique above yet, but I have some material that I'll probably have to do this with simply due to size.
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tkvancil
fully equipped rock polisher
Member since September 2011
Posts: 1,546
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Post by tkvancil on Jul 29, 2018 9:14:22 GMT -5
Hammering or crushing can work. I think it works best for rocks that already have fractures. Easy enough to break along those fractures without causing more.
Cutting a score line with the tile saw then breaking definitely creates less waste. The saw "nub" will need to be cut off and the shape is less "natural".
Pre-shaping is the individuals choice, some do, some don't. It will speed up the coarse grind without a doubt.
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Post by grumpybill on Jul 29, 2018 11:33:17 GMT -5
Although this particular rock was granite, which cleaves easily, these photos illustrate my method. The trick is to cut the notch deep enough and use a wedge/chisel that tapers quickly. You don't want the wedge/chisel bottoming out. You want the force from each hammer tap to push laterally, not downward. ( Note: This method doesn't work as well on rocks that fracture conchoidally or on brecciated jasper that isn't well healed.) To give you an idea of the size of the rock: I tried to make use of an existing fracture. The tools I used. Although someone had obviously been beating on the stone wedge with a sledge hammer, a 2 or 3 pound mash hammer is all it takes. Here you can see the end result with the notch from the saw. Had I wanted less smooth/flat area, I'd have made several smaller notches around the perimeter and tapped each in turn.
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peachfront
fully equipped rock polisher
Stones have begun to speak, because an ear is there to hear them.
Member since August 2010
Posts: 1,745
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Post by peachfront on Jul 29, 2018 18:14:44 GMT -5
I am a total noob to the whole rock tumbling game. I recently picked up some large pieces of jasper with the intention of tumbling it. I was breaking up a large cantaloupe sized rock with a hammer and this question came up. I am sure wasting a lot of material by smashing it with a hammer. I end up with all different sized rough. Then i end up destroying the bigger pieces when trying to make them a tad smaller. So what do you guys do with your oversized rough? Do you try to give it a basic shape before tumbling? I have a tile saw and could trim these up a little. Thanks Travis It's a matter of taste but I have a small tumbler so I prefer to work with smaller pieces. We bought a rock saw, and hubby saws the pieces down to more manageable sizes. Next, I do some rough grinding on a diamond cabbing wheel. Last comes the tumbling. This is the great thing about the hobby. You can do as much or as little as you want, and there is usually an economical workaround for beginners. There are no rules. You can't mess up.
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shadyatbest
off to a rocking start
Member since November 2016
Posts: 23
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Post by shadyatbest on Jul 29, 2018 22:53:53 GMT -5
Thanks for all the replies. Tile saw it is.
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kskid
Cave Dweller
Member since July 2014
Posts: 98
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Post by kskid on Jul 30, 2018 0:38:00 GMT -5
Sounds like you've already reached a decision, but just to add an alternative opinion - I do break large rocks as grumpybill described to get them small enough to tumble. I tried using a saw to cut out cracks, holes, etc. It did reduce the tumble time considerably, although it added hands on "manipulation" time. But I always felt like the finished product had been adulterated somehow; they never looked quite as natural as those I hadn't trimmed. It was easier to get my head around the longer tumble time than it was to break my OCD preoccupation with the "unnaturalness" of the trimmed rocks. Crazy, I know, but as is often said in here, "They (rocks) only have to satisfy you". Happy tumbling!
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lancemountain
starting to spend too much on rocks
Member since March 2017
Posts: 214
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Post by lancemountain on Jul 30, 2018 21:01:35 GMT -5
Sounds like you've already reached a decision, but just to add an alternative opinion - I do break large rocks as grumpybill described to get them small enough to tumble. I tried using a saw to cut out cracks, holes, etc. It did reduce the tumble time considerably, although it added hands on "manipulation" time. But I always felt like the finished product had been adulterated somehow; they never looked quite as natural as those I hadn't trimmed. It was easier to get my head around the longer tumble time than it was to break my OCD preoccupation with the "unnaturalness" of the trimmed rocks. Crazy, I know, but as is often said in here, "They (rocks) only have to satisfy you". Happy tumbling! I like this- rocks should have their own personality. I would like to find a good grinder to smooth out small cavities but I do agree with this
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kskid
Cave Dweller
Member since July 2014
Posts: 98
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Post by kskid on Jul 31, 2018 23:31:41 GMT -5
Hi lancemountain. You'll have to do some searching, but I've seen a lot of posts here over the years describing many different methods. Everything from low tech to high with prices that match. The most frequent seems to be a repurposed low end tile saw with a diamond blade. Not very precise, but readily available & effective. Happy tumbling!
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Post by parfive on Aug 1, 2018 1:26:33 GMT -5
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gatorflash1
spending too much on rocks
Active in Delaware Mineralogical Society, Cabchon Grinding and Polishing, 2 Thumlers B's and a UV-18
Member since October 2018
Posts: 375
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Post by gatorflash1 on Dec 7, 2018 16:03:57 GMT -5
Sitting in the center or middle of an 8' x 8' tarp to catch the split rock chunks, I have a 1" thick x12" x12" wide piece of steel onto which I lay a 3/16" steel rod. Then I put the bottom of rock I want to crack centered over the steel rod so it sort of teeter-tooters. If the rock has a crack that is what it goes over the steel rod.
Then I take either my rock hammer or rock chisel, place it on the top side of the rock which is sitting on the steel rod. Then I hit the hammer side of the rock hammer (with the pointed side sitting on the rock), or the chisel sitting on the rock with a 4lb hammer, gently at first. This usually splits the rock into a couple of pieces. Then I repeat the same thing with the pieces until I get them to the size of tumble I'm are looking for. It doesn't take much time. The hardest part was finding a nice big piece of steel onto which everything sits. I wear my construction boots, gloves, pants and shirt and safety glasses when doing this. It goes very fast, only taking few minutes to accumulate a bucket of tumbling rough. I have a trim saw that I use for cabs but this is faster than using the saw.
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scottyh
starting to spend too much on rocks
Member since November 2007
Posts: 181
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Post by scottyh on Dec 26, 2018 16:00:18 GMT -5
Personally if my rough is to big I design a bigger tumbler 😁😁😁😁, but seriously I do. However, if the rough is too big I use a hydraulic press to split it into smaller pieces then give them a quick grind to take out the worst of the flaws then I tumble. Cheers Scott
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