zekesman
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Member since May 2016
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Post by zekesman on Jun 10, 2017 14:54:22 GMT -5
Been cutting cabs a long time, new to tumbling. Will it help to speed things up in the coarse stage to add more grit at the start? Or is it better to just add some every 5 days or so? I know patients. Vic
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rollingstone
starting to spend too much on rocks
Member since July 2009
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Post by rollingstone on Jun 11, 2017 2:56:46 GMT -5
Good question. I don't think I know the answer for certain though. Most people try to not use any more grit than needed at any stage since using more than needed just seems a costly waste. Would adding extra grit in coarse grind speed thing up???... Maybe .... Maybe not. For what it's worth, my bet is, "NOT"
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jamesp
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Member since October 2012
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Post by jamesp on Jun 11, 2017 7:28:05 GMT -5
Coarse grind can be wasteful. Once the grit has broken down to 220 it ain't gonna shape your rocks much at all. Add 30-46-60 or whatever you are using. If you don't do clean outs and simply adjust your slurry you are keeping the smaller than 220 particles in the barrel for whatever small effect it may have.
I have five 6 pound barrels. I know them well. They get the same recipe over and over. Those barrels were opened at 12 hours-24 hours-48 hours when first commissioned. I separated the grit from the rock and found out when those big SiC particles were reduced to nothing. That dictated when fresh grit was added. It was a one time effort to find the break down time. Once the amount of time was figured out I never looked back. Recipe done. In my case, standard dose fresh grit every two days, or if pushing, 75% doses every day. I do use clay slurry thickener at start up.
If increasing dose, I would have to run the break down check all over again. Never tried it.
I do know it is time to trash a piece of sandpaper the moment it is worn out and grab a fresh sheet. There is no substitute for fresh abrasive. Plain fact.
-break down time-
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tkvancil
fully equipped rock polisher
Member since September 2011
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Post by tkvancil on Jun 11, 2017 7:52:19 GMT -5
I toyed around with adding extra grit at one time. I found that there was a "breaking point". At the time I was roughing in 6# barrels. Increasing the grit by 50% did grind okay but left unused grit after a week. At 25% more there was no left over grit. Both additions to my usual formula did little as far as removing material. It was measureable by weight in vs. weight out, but so slight that I thought it was not worth the extra.
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Wooferhound
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Lortone QT66 and 3A
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Post by Wooferhound on Jun 11, 2017 8:53:57 GMT -5
If you are grinding rock then your grit is breaking down into powder. If you are not grinding rock then the grit will stick around for awhile. Open up the barrel and give it a a look and a feel. If the grit is still there then close it up and spin it some more. If the grit is gone, then add some more and give it another spin. If the grit remains after a few days then you are not aggressive enough in your grinding method.
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Post by coloradocliff on Jun 11, 2017 9:20:34 GMT -5
The clay slurry thickener that James was talking about can be clay based kitty liter. Plain ole Wally world, unscented no additives stuff. I use about 12-16 oz in a 15 lb. barrel( 2/3 full total) for when first starting the rough. After a few days when grit is broken down,( By feeling the malt) Milkshake too thin, malt thickness just right. Just have to experiment. Pour off SOME of the ole thickened gravy with spent grit. Fill back up to level with water, add more coarse and bam, off you go. Keep it thicker by not over doing the water or pouring off too much of you thickening. The brand I use is called Kitty Diggins. Tis thicker slurry right off the bat will really help to avoid chips and bruises early on that will really screw you up.. We all screwed up rocks before but pad those rough ones early on. Rotary is where you really need a thicker slurry. Have a good one Vic. Plus 1 to what James says. he's the best. All good advice here this am. C
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Post by morerockspleaz on Jun 11, 2017 9:39:38 GMT -5
Your first load is always a learning experience. Once you learn your rocks and your tumbler it get easier. Everyone has their won recipes and methods you can try more grit but it usually is wasted. Listen to jamesp and many others they are giving you good advice. Once the first stressful load is over it gets easier. Take your time, that's hard but you will be rewarded with nice shiny rocks. I have 4 Qt 12's turning right now in course. Course is the longest stage. Welcome to tumbling. Its very addictive.
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jamesp
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Member since October 2012
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Post by jamesp on Jun 12, 2017 7:50:08 GMT -5
If you have a good slurry creating near perfect distribution of grit particles then any slurry you sample should have grit particles in it. And simply rubbing this good slurry between finger and thumb should give you a good idea of the size of your grit particles. Which is a heck of a lot easier than doing a full clean out and separation to observe grit.
Also, if you run 30-46 or 60 you will see the particles of grit in the slurry that is coating the rocks. But once particles are 120 and smaller it is not easy to see the particles of grit. But can be felt between finger and thumb.
Good distribution of grit has to be a big player in effective grinding.
Bigger doses can be related to adding fresh grit more often. 75% doses daily verses 100% doses every 2 days....
If a dose is 1 cup:
75% doses daily = 7 X .75 = 5.25 cups/week 100% doses every 2 days = 3.5 cups/week
Dose rate is higher, not the dose.
Doubt that it is a good idea to put 5 cups in the barrel at the start of 7 days. Limitations of the slurry to distribute the grit particles is probably a problem. Be ready to accept the fact that the grit particles will settle where you don't want them to settle.
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Post by rockpickerforever on Jun 12, 2017 9:10:46 GMT -5
jamesp , I am still following your lead and adding grit (30SiC) every two or three days. It works great for me! Will have to post my last batch, as I have another one almost ready for finishing in the vibe. Yes, more grit usage costs more money, but shortens the length of time for the tumble - significantly. Longer tumbling time equals higher electric bill - Yikes! I think it is pretty much a trade off, 'cept you don't have to wait so long. Patience is not my strong suit.
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jamesp
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Member since October 2012
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Post by jamesp on Jun 12, 2017 11:51:01 GMT -5
jamesp , I am still following your lead and adding grit (30SiC) every two or three days. It works great for me! Will have to post my last batch, as I have another one almost ready for finishing in the vibe. Yes, more grit usage costs more money, but shortens the length of time for the tumble - significantly. Longer tumbling time equals higher electric bill - Yikes! I think it is pretty much a trade off, 'cept you don't have to wait so long. Patience is not my strong suit. Hopefully maintaining fresh grit does the rocks faster for the same amount of grit AND less electricity. Difficult to measure coarse grind rates. Got no solution for patience. Contemplation of naval ? Hot compresses ? Yodeling !!
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Fossilman
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Post by Fossilman on Jun 14, 2017 13:27:14 GMT -5
I keep my slurry from the 1st and 2nd stags of tumbling,just add grit to them(when its time to add water,I just add the slurry)plus a bit more grit..and roll away....
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jamesp
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Member since October 2012
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Post by jamesp on Jun 24, 2017 6:31:28 GMT -5
Thinking about zekesman 's thread here I did an overdose of grit last week. One full cup of SiC 30 in a 6 pound rotary turning at a fast 55 RPM with clay thickener for instant slurry development. One full cup is about double what I normally use for 6 pounds. I assumed the slurry thickener AND fast 55 RPM would easily circulate the extra grit. Plus there was a one pound crusher rock in the barrel, filled to 80% for padding the big rock. After 2 days there was not one iota of SiC 30 left, broke down to nothing. Did a careful separation and hunted 30 grit particles-none. Very pleased with performance on this pre-ground rock after only 2 days. Before with deep 30 grit diamond scratches from the diamond wheel: Smooth as a baby's bottom 2 days: Conclusion, rotate fast and add slurry thickener allows overdose of coarse grit. Reap fast grind rate. Usually takes 5-9 days and 2-3 normal dose(1/3 to 1/2 cup) grit additions. Very pleased with results. Will make this standard procedure for the 55 RPM shafts. Will try same on 30 RPM shaft.
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jamesp
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Post by jamesp on Jun 24, 2017 6:56:41 GMT -5
Will do same overdose on this one pound sphere shape. Has much deeper grind marks. Pretty sure the deeper grind marks will require a cup every 2 days for either 4 or 6 days. Perhaps longer. Will give notjustone 's bulk grit a try on some of these pre-grind overdose runs. Compare screened SiC 30 to his bulk stuff. ID on this rock greatly appreciated.
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notjustone
spending too much on rocks
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Post by notjustone on Jun 24, 2017 8:21:36 GMT -5
Will do same overdose on this one pound sphere shape. Has much deeper grind marks. Pretty sure the deeper grind marks will require a cup every 2 days for either 4 or 6 days. Perhaps longer. Will give notjustone 's bulk grit a try on some of these pre-grind overdose runs. Compare screened SiC 30 to his bulk stuff. ID on this rock greatly appreciated. I am going to try a run with less probably 60 percent full in at least 1 of my barrels when I do my cleanout this weekend. I'm finding the big chunks of sic are actually rounding off instead of breaking down. I seal them up and let them run for a week at a time with no additions. ive been running pretty full 75 to 80 percent in 8" pvc barrels at 37 rpm. or I may fire up the wood lathe and turn a larger drive pulley and speed up my bottom shafts. I'm not really sure if it cuts faster than 30 grit. but since its free and I still have a couple hundred pounds of it ill continue to use it.
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jamesp
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Member since October 2012
Posts: 36,158
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Post by jamesp on Jun 24, 2017 9:09:14 GMT -5
Will do same overdose on this one pound sphere shape. Has much deeper grind marks. Pretty sure the deeper grind marks will require a cup every 2 days for either 4 or 6 days. Perhaps longer. Will give notjustone 's bulk grit a try on some of these pre-grind overdose runs. Compare screened SiC 30 to his bulk stuff. ID on this rock greatly appreciated. I am going to try a run with less probably 60 percent full in at least 1 of my barrels when I do my cleanout this weekend. I'm finding the big chunks of sic are actually rounding off instead of breaking down. I seal them up and let them run for a week at a time with no additions. ive been running pretty full 75 to 80 percent in 8" pvc barrels at 37 rpm. or I may fire up the wood lathe and turn a larger drive pulley and speed up my bottom shafts. I'm not really sure if it cuts faster than 30 grit. but since its free and I still have a couple hundred pounds of it ill continue to use it. Rolling these pre-ground rocks over and over has given me a good data base. They are short runs to simply shave off grinding marks. Predictable and measured-REMOVE THE GRIND MARKS. It won't take long to get some results from your bulk grit. It either will or will not remove the grind marks in normal time that SiC 30 removes them. The grind marks are all similar. Oh yea, if it takes bit longer no problem. The price is right ! 37 RPM for a 8 inch barrel is like 8/6 X 37 RPM = 49.3 RPM with a 6 inch barrel. BUT, the 8 inch barrel has mechanical differences. Bigger diameter barrels may magnify the grind in some ways. I ran 8 inch PVC at 30 RPM, it seems to be about the same grind rate as 6 inch barrels at 55 RPM. Personally, I would leave it at 37 RPM. Surprised the SiC chunks did not break down. The SiC being similar to glass fragile. PS I put the bulk grit in with the sphere in the photo today to see how it grinds.
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