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Post by rocklicker on Nov 9, 2009 4:14:21 GMT -5
OK, this is proabably obvious, but I got to ask...
When you measure for tumbling, do you use heaping tablespoons or level ones?
I ask beacuase I noticed some rough grit not broken down in the bottom of my barrels today. They had been running for two weeks and I recharged 1 week into it. I use heaping tablespoons usually but wonder if I am using too much.
BTW, my grit rule up to date has been: 1 cup of grit per 15 lb hex barrel turning at 23 RPM. Too much? Somewhere along the way I must have decided 15 rounded Tbsp was a cup. For the 3 pound barrels I use 1 rounded Tbsp per pound. Should I be using level Tbsp to measure?
Thanks,
Steve
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Post by Toad on Nov 9, 2009 7:00:54 GMT -5
I always used level in my 12-pound, until I wised up and found a conversion calculator on-line and figured out that 1 and 1/4 cups was equivalent for however many tablespoons I was supposed to be using - so much better than counting. I think they were slightly rounded but not heaping. Never had any problem with grit. Don't know what the rpm was - it is a lortone.
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Post by 150FromFundy on Nov 9, 2009 7:25:17 GMT -5
Could be too much grit, or could be an overcrowded barrel, or too much water. If there is not enough action in the barrel, the grit does not get broken down. Make sure your barrel is no more than 2/3 full and the water is just below the top layer of rock.
Darryl.
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Post by connrock on Nov 9, 2009 7:32:49 GMT -5
Steve, I used to be methodically precise in measuring my grit but found that it's not really necessary. I have and still use the rule of thumb method that is 1lb of rough grit for every 10 lbs of rocks. The whole thing boils down to the ratio between rocks, grit and water. If the barrel is filled correctly with rocks I have found that using too much water can be a problem in roughing.I probably use much less water then the "norm" but it works for me so I continue to do it. Another thing to consider is what size grit you're using for roughing. Some folks use 60/90,some use 80 and so on and so on. The more coarse the grit is the less water should be used. If you use a very coarse grit and the normal amount of water all you'll do is wash the rocks in gritty water and won't create a slurry at all.Just gray water after weeks of tumbling. The size (s) of the rocks is also a factor. Lets go back to the basics,,,,,, A proper load = a mixture of different size rocks with at least 1/3 of the rocks being no bigger then 1/2" A proper load= filling the barrel at least 1/2 full but no more then 3/4 full A proper load= 1lb of "60/90" grit for every 10 lbs of rocks being tumbled. A proper load= filling the barrel with water up to just under the top layer of rocks or a tad less. In my opinion if the above is used it won't matter if you use heaping,level or shallow spoonfuls of grit.  CONNROCK |
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rockdewd
has rocks in the head
Member since October 2007
Posts: 605
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Post by rockdewd on Nov 9, 2009 15:48:15 GMT -5
I have found that the following quantities of 60/90 and time work for me:
15 lb barrel - 2 cups grit - tumble one month
12 lb barrel - 1 1/2 cups grit - tumble 3 weeks
6 lb barrel - 3/4 cup grit - tumble 2 weeks
All barrels turn at 16 RPM
YMMV but this is what works for me. I'm tumbling Jaspers, Agates, and Petrified Wood. When I clean out the barrels following that schedule the grit is almost totally broken down and gone. There is a nice thick slurry in the barrel. I found that when I cleaned out earlier I was wasting a lot of grit.
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Post by rocklicker on Nov 10, 2009 2:34:29 GMT -5
Thanks for setting me straight. Conrock, I think a scale is what I need. I'm pretty good about the water level, but adding more grit carriers looks like the answer. BTW, this is home built tumbler so I can change the rpm's easily. I may consider slowing it down. I run it at 23 rpm, which is the high end the book I go by recommends.
I think I have somehow changed my tumbling methods over time for some reason and lost track of how it should be done. ;D
Steve
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Post by connrock on Nov 10, 2009 7:05:53 GMT -5
The "grit carriers" or the lack of using them,is a HUGE problem but we all do it at times!
I think it's one of the biggest problems and unfortunately the most common!
connrock
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