matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 2, 2015 15:27:35 GMT -5
Hey Everyone,
I'm fairly new to the whole rock tumbling scene, but want to pose a questions to the community. What is the best method and tumbler to use for larger stones? (Fist sized) I'm able to self-collect a lot of larger sized stones that won't fit in a 3lb barrel.
I'm leaning towards purchasing the Thumbler Model B - 15lb tumbler. It seems to have a good reputation for durability and would fit one or two large stones with a batch of smaller stones. Is there a better one for a similar price range?
Also, does anyone have tips for polishing larger stones? Is the process pretty much the same as smaller ones or do you do things a little differently? I'm planning on preforming them with a trim saw and grinder to get the general shape roughed out, then running through the normal stages 60/90, 120/220, 500, polish, burnish. Do you need more filler to prevent cracking? is a larger stone going to pulverize the smaller ones? What's the largest size stone you can polish in a rotary?
I know, I know, a lot of questions here, just want to get everyone's opinion before I pull the trigger on the Model B.
Thanks, Matt
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Post by captbob on Jan 2, 2015 15:34:37 GMT -5
I have 4 Model B tumblers. Haven't tried any other brands, but I love the Model B.
shop around!
I'm on a yard work break, will be back or others can work on your other questions.
Justa FYI - Kingsley North has a good sale on 80 grit - 45lbs for $59 + shipping = 75 bucks. Hard to beat that, and if you're getting a 15 pound tumbler, you're gonna need it.
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matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 2, 2015 15:41:08 GMT -5
Thanks for the tip, but i'm a step ahead of you, Captbob. just ordered a bag of the 80 grit last week. haha. Too bad I can't find old Carbide wheels like Jamesp to use.
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jamesp
Cave Dweller
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Post by jamesp on Jan 2, 2015 18:59:10 GMT -5
Some rocks are friendlier than others. Hard agates take a lot of abuse. Obsidian over 1.5 inches gets bruises easy. Rose quartz and amethyst bruises easy. Rhyolite and unakite is tough. Best thing to do is put 3-6 half pound agates in with a bunch of medium and small agates and give it a try. I tumble a lot of silicified coral and may fill a 15 pound barrel with 12-15 rocks over a half pound with a lot of small rocks till the barrel is 7/8 full for a gentler tumble.
Best to use a mix of sizes and get your groove before doing big stuff.
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Post by johnjsgems on Jan 2, 2015 20:39:09 GMT -5
The B is a good tumbler. Try checking the reloading suppliers. Cabellas and others sell the Model B pretty cheap (or did when I was a dealer). Same tumbler. Always order extra lid gaskets or make your own. As long as the fist size rocks are mixed with smaller/medium rocks of similar hardness you should not have an issue. Best to keep barrel about 3/4 full, 2/3 at absolute minimum. Figure one tablespoon per pound same as 3 lb. barrel. If you have a lot of unground coarse grit after 10-14 days cut back a little. The barrels are not cheap but a dedicated polish barrel would save you money on polish pretty quickly.
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matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 2, 2015 21:07:30 GMT -5
Jamesp - I'll be doing mostly pet wood and agates (locally collected stuff), so I think they can take the abuse. I'll probably be using the model b mostly for rough tumbling, and finishing them on the AR2 until I get some experience under my belt.
Johnsgems - how does having a second barrel for polishing save money?
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Post by Toad on Jan 2, 2015 21:59:46 GMT -5
Polish can be reused, so if you have a dedicated barrel for polish, you don't lose any by cleaning it out. At least that's what I think John means.
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Post by Toad on Jan 2, 2015 22:05:13 GMT -5
By the way, I've heard nothing but good things about the Thumbler, but I'm a Lortone guy - I use the C200. It runs two 12-lb barrels and has plenty of motor.
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matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 2, 2015 22:17:17 GMT -5
Interesting, I had no idea you could re-use it. How exactly do you re-use it? do you leave it wet in the barrel or what?
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
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Post by quartz on Jan 2, 2015 23:03:24 GMT -5
I reach in the polish barrel [rubber gloves], grab a few rocks, and shake them off over the barrel before washing. Saves most of the polish. I add about 1/4 of what would be a full load of polish at each washup. As far as how big of rocks can be tumbled, I've done a few in the 7-8 pound range in homemade 5 gallon barrels. Certainly someone has done bigger.
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Post by captbob on Jan 2, 2015 23:49:38 GMT -5
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rodeodan
starting to spend too much on rocks
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Post by rodeodan on Jan 3, 2015 0:42:01 GMT -5
If you are tumbling large stones, I would recommend one large and lots of smalls. Any time I have added too many bigger rocks, they end up with crescent shaped impact cracks all over. Good luck and keep us posted of your progress!
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Post by captbob on Jan 3, 2015 0:54:41 GMT -5
That reminds me. Buy ceramic media Matt. Search for deals on eBay if you use that site. Patience will bring you way better deals than at any online rock shop I've found. Search all categories, not just the Rocks & Minerals section.
I use plastic pellets in the later stages as well. LOTS of them with softer stones. Again, better deals can be found on eBay. ALL categories! Might find the best deal on those in the doll section or somewhere odd like that. Many old bean bag chairs had plastic pellets in them in you can find one.
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jamesp
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Post by jamesp on Jan 3, 2015 1:10:13 GMT -5
I tumbled this 16 pound batch just as it is laid out. Lots of bigs, but it is a very hard/tough material. biggest was 12 ounces. Even the sharp points did not get bruised. Some material can take the abuse. not the best photo to show the polish, note the sharp edges are not bruised.
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matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 3, 2015 10:31:20 GMT -5
I guess I'll have to experiment and see how much fill to use for cushioning. I'll probably start with more and then back off until I start getting bruising. At least with more fill the only thing I risk is the batch taking longer. My gut feel is that the agates here are on the tough side, being glacier wore and river tumbled to start with minimal fracturing.
That's it, I'm pulling the trigger on the Model B. Thanks everyone for your input!
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hornseeker
spending too much on rocks
Member since January 2014
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Post by hornseeker on Jan 3, 2015 15:01:17 GMT -5
Does anyone have any experience with putting a BIG rock in say a12-15 pound barrel... lets say a rock that is just 2 inches diameter less than the inside of the barrel? And putting in a lot of fines and letting itgo? I have a big rounded, nearly polished jasper cobble that I am dying to polish....
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Post by captbob on Jan 3, 2015 15:16:03 GMT -5
Ernie, the manufacturers recommend up to half the size of the barrel opening as the largest. I've pushed that a bit, but nothing as large as you're talking about. Get a bigger tumbler if you want to go bigger! I'm going to build a tumbler and buy a 40 pound barrel. Huge savings over buying an entire 40 pound unit unless I can find one used before hand.
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Post by johnjsgems on Jan 3, 2015 15:50:25 GMT -5
My mistake. I didn't realize they were selling the high speed versions. I don't think 2" smaller than opening would allow rock to roll with barrel. Sounds like a 40 lb. tumbler is what you need. You can find used HP 40 lbs. sometimes. I think I paid about $200 for the one I had. And yes, polish doesn't break down so can be reused. You also won't get grit contamination providing rock and media is well washed before going in the polish barrel.
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Post by captbob on Jan 3, 2015 17:44:24 GMT -5
John, I have to say that you were correct in that you wrote (bold part): The B is a good tumbler. Try checking the reloading suppliers. Cabellas and others sell the Model B pretty cheap ( or did when I was a dealer). I bought my first 3 Model B tumblers from Buffalo Arms way back when, and they were all the 1550 RPM units. I knew to ask and that was what they stocked. Maybe they didn't know about the higher speed model. (?) But, you are correct. They used to sell the rock model. And, they were WAY less expensive than buying from any rock shop! Deals just aren't as easy to find as they used to be.
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matt2432
starting to spend too much on rocks
Member since December 2014
Posts: 171
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Post by matt2432 on Jan 3, 2015 18:01:03 GMT -5
Do you need to keep the polish from drying out or anything? What if your only running a polish batch every 4 months or so?
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