richardh
spending too much on rocks
Member since June 2016
Posts: 391
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Post by richardh on Dec 5, 2016 12:53:41 GMT -5
I am now getting consistent results in my 3lb HF barrel with 30 grit SiC. The key seems to be using enough cat litter. Just as I was about to give up on the SiC 30 I decided to really put a lot of clay in to make the slurry really thick and it worked. After 5 days the grit was totally broken down and the rocks actually had a bit of a sheen on them.
I went back and tried to figure out exactly how much I really needed and the following formula seems to be working great.
I fill the barrel about 60% full with rocks then fill with water to a little below the top of the rocks (maybe 3/4” from the top) then I add 4 tbsp of SiC 30 and 4 TBSP cat litter. The grit has broken down after 3 days every time I have tried this mix so far.
I just though I would put it out there since I got the impression that I wasn’t the only one who was struggling with the SiC 30. JamesP was right, I was just too afraid of thick slurry and never got mine thick enough before.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Dec 7, 2016 7:23:39 GMT -5
I don't have experience with small rubber lined barrels. They should be the least aggressive barrel of all barrels. Your finding does not surprise. I do know one thing, a slurry that is quite thick and has a lot of 'suction' force will flat out grind some rocks. And protects them for a more aggressive 60% fill. Protect bigger and softer rocks from bruising.
That is a big finding Richard.
You may think about adding a half dose of grit every 2 days to maintain a supply of bigger grit particles.
I too experience the sheen after extending the run(in your case 5 days). The thick slurry scavenges the smallest of grit particles and grinds them very finely. That sheen is in the neighborhood of a 1000 finish. Allows skipping 220 and 500.
Faster grind, skipping grit stages = win win.
I would avoid the cat litter using 1000 and finer. It may have abrasive particles that slow you polish steps. Do gentler 75% fill for finish steps, so add some media or pea gravel or semi tumbled smalls to make up difference from 60% to 75%.
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