robbiejohn
starting to shine!
Member since July 2010
Posts: 36
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Post by robbiejohn on Sept 17, 2010 19:16:02 GMT -5
Hello everyone, I hope this the right place for my inquiry. I pretty much a newbie having jumped in with both feet and surfing up the learning curve with lots of good luck. Now, I don't know if my luck has run out or even improved. I bought for $200 a 10" slab saw, a grinder/polisher etc, 1-2 tons of various rough rocks about 30 lb each and 4 of Lortone's largest barrels in good shape. No tumbler to be found. I'll guess it was home made, as my new one will be. The rocks in pails have all been tumbled and polished at some time, possibly up to 25 years ago. They weren't very well done. About 1/3 of the stones are of normal 'pebble' size, but the other 2/3 are up to 3" across and weigh 8-12 oz. All of them have some areas of really smooth and shiny polish as well as dull areas. Many have cracks and chips. I've put a couple of loads of the smaller material through my Lot-O and they've come out beautiful. What can I do with the big ones? Can I use a saw to cut them into preform size pieces---then maybe tumble them? I'm afraid to take a hammer to them as some are really attractive stones. I can't identify most of them. What do you think of the idea of cutting up the stones and seeing if I can salvage some by re-polishing? Any other advice is welcome. Thanks to all for a wonderful site with helpful info. Cheers! from Robbiejohn.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 17, 2010 19:40:14 GMT -5
Howdy Robbie: While I have been guilty of breaking up lots of material with a hammer, the really nice material is best chopped up with a saw like your ten incher and then you can tumble the preforms. The ten inch saw should allow you to handle rough up to about 4 1/2" x 3 1/2" or so really easily and then you can use it on the resulting slabs as a trim saw to make shapes that you might find more pleasing. Your Lot-0 should work swell for polishing preforms without a lot of change in shape but you will obtain a better polish on the flat portions if you make sure and included lots of small stones with your flat pieces to increase surface to surface contact. Fractured rough or less desirable stuff can be whacked up with the hammer to give you the small stones to fill out your loads. Materials that have very shiny parts along with dull spots might be of mixed hardness which makes them undesirable for tumbling or they may have just been done in a sloppy manner with not enough contact between surfaces so some spots did not polish properly. This can happen with preforms with flat surfaces when you don't use enough small filler.....Mel
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robbiejohn
starting to shine!
Member since July 2010
Posts: 36
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Post by robbiejohn on Sept 17, 2010 19:48:25 GMT -5
Mel, thanks for the encouragement and info. I should have all the stones sliced up by 2035. Ah well, it's the journey itself that counts most. Now I have to get rust off the slab saw and build a lapidary shed. Robbiejohn.
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Post by tkrueger3 on Sept 17, 2010 20:35:34 GMT -5
Robbie, I too have recently come into possession of a slab saw and a big pile of rocks. The trap I've fallen into is that I'm having so much fun cutting up rocks and finding purty stuff that I've kinda abandoned a lot of my other duties - housework, wire-wrapping, cabbing, housework, etc. But then, I'm single, so who cares - I'm having a ball!
Welcome to the slabbing fraternity!
Tom
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Post by johnjsgems on Sept 17, 2010 20:57:05 GMT -5
Since you have a grinder you can also grind out the bad flaws and start them again. If you have Lortone 12 lb. drums you can throw a 3" rock or two in the load (when you build the tumbler). I wish I could happen on to some 12 lb. Lortone drums. I picked up a QT66 but would really like the larger drums for it. The 6 lb. drums are labeled "Pre Polish" and "Polish" so both are like new. A 12 lb. or two for the rough steps would be ideal.
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robbiejohn
starting to shine!
Member since July 2010
Posts: 36
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Post by robbiejohn on Sept 18, 2010 2:29:19 GMT -5
Hi Tom, I'm having great fun too. My wife looks at me with a really funny look these days---as if to say: "I'm not altogether happy with all this rock business, but he'd probably be harder to handle without his stones to play with". Besides, every time I dry off a beautifully polished batch from the Lot-O, her eyes light up as brightly as mine. I happen to have three jobs: organic farmer, country parson, and crisis counselor. I love them all; but all I want to do is play with stones. I suppose/hope this will settle down soon. Special thanks to John at JS Gems for the simple idea of grinding bad flaws out of bad stones and starting again. When the new tumbler's ready I'll have lots of fuel for the big barrels. Though I have 4 barrels, I think I'll make it only big enough for 3 at a time. That way I can use 1,2 or 3 at a time as needed. From what I've been reading, it seems that the very large barrels can smooth and shape rough material quite a bit faster than the smaller machines. I'll be looking around for a bulk source of 60/90 grit (or even coarser). It's interesting how dreams and fantasies about rock processing vary in accordance with the available equipment. 6 weeks ago I was delighted with my little Lortone 33B thinking it would last me forever. Now, it's relegated to rough primary shaping only and I'm off to greater things with the vibe and the anticipated 36-pounder. Better slow down for a breather. Still working out 'how to post pictures for moving idiots'. I'll get some up soon. Cheers to all, Robbiejohn.
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Post by jakesrocks on Sept 18, 2010 9:36:35 GMT -5
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Post by jakesrocks on Sept 18, 2010 10:17:38 GMT -5
Oh, let me add, Black Diamond and other blasting grits are available at Menards, Home Depot, Tractor Supply and many other places. No extra shipping charges, and no waiting on FedEx. Don
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 18, 2010 18:20:29 GMT -5
Wow guys, that Black Diamond is really inexpensive. Is it silicon carbide or is it something else? I actually have a tractor supply right near our ranch and that would be super cool to have an inexpensive source of coarse grit as I go through a lot of it.....Mel
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Post by jakesrocks on Sept 18, 2010 18:35:05 GMT -5
Mel, I'm not exactly sure what it is, but I've used it to sand blast rock, and it does a good job etching quartz. I used to bring enough home from work to charge my tumblers, and it worked good for the first stage. The place I worked for bought it by the ton, and didn't mind if I took a pound or so home once in a while. Don
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 18, 2010 19:38:53 GMT -5
*L* Well, at $7.99 for fifty pounds, I"m sure gonna give it a try if I can find some in 80 or 90 grit or thereabouts....Mel
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carloscinco
fully equipped rock polisher
Member since July 2008
Posts: 1,639
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Post by carloscinco on Sept 19, 2010 14:04:13 GMT -5
Black Diamond is 99% coal slag and 1% quartz silica according to their MSDS sheet. I don't know if that is good or bad for our purposes.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 19, 2010 15:14:54 GMT -5
Hmm I just checked and the hardness for Black Diamond is listed as mohs 7. Since that's the same hardness as agate and jasper I would think it would probably take much longer to coarse grind than with silicon carbide at mohs 9 -9.5.....Mel
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slabcabber
has rocks in the head
Member since April 2010
Posts: 590
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Post by slabcabber on Sept 21, 2010 9:02:10 GMT -5
Don how long do you have to run the corse grind in the 90 grit Black Diamond? Do you have to run it longer than with the silicon carbide? And if so, on average how much longer?
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Post by jakesrocks on Sept 21, 2010 9:28:18 GMT -5
I haven't used black diamond for quite a while, but in my 15 lb barrel, I used to run it for a month. I should point out that this material is very sharp, and may cause more wear on your barrels. Don
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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 Sept 21, 2010 11:43:43 GMT -5
I remember other grit discussions which seemed to conclude that only SC coarse grit was effective(cost and otherwise). (I think AO rounded as it broke down rendering it less effective than Sc which cracked into smaller , still sharp grit). This discussion seems to point at using a mixture that is 99% coal slag and 1% quartz silica and still effective at shaping rocks. Anyone else have experience with this material?
Charlie
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