jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jan 22, 2020 11:01:58 GMT -5
We are having 18F and 20F mornings here in Atlanta Georgia. I have a Vibrasonic vibe doing a AO 220 pre-polish and an AO 14,000 polish out in an open air shed in sugar slurry. The Vibrasonic has a large motor that heats the hopper from below. Cold sugar slurry is thicker than summer slurry. It made a big difference. Pulled glass in AO 220 after 36 hours and noticed a premature 3 day pre-polish. Shut down, cleaned out, started the AO 14,000 polish. Pulled glass in AO 14,000 polish at 4 hours and found them finish polished. Ran 4 more hours. Shut down and did clean out. Results with pea gravel media
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jan 24, 2020 7:08:59 GMT -5
"The no-grind coarse-grind start up syndrome" quantified.
In tinkering with watery and thickened slurries over the years I have noticed wasted time rolling rocks in coarse grind in the rotary at start. Using glass for an example. Glass shapes fast so the grind rate is fast and easy to measure. Shaping time varies 5 to 12 days depending on abrasive size and slurry.
Case #362(not really but has happened many times) In using the SiC 10 with a medium thickness(1.5 cups clay) there was virtually no grinding taking place for the first 3 days. Barrel had the same rumbling sound after 3 days as the day it was loaded. Glass looked about the same as the day it was loaded into the barrel. Little wear. Day 4 I went to the tumbler and could barely hear the glass rumbling in the barrel. Little rumbling means the slurry has thickened. Opened it up and the grind had started and the glass showed significant wear and yes the slurry had thickened due to the glass wearing. Way more wear in the last 24 hours than in the first 72 hours. Closed it back up as is and came back 2 days later only to find the glass had worn almost too thin.
Conclusion was simple, the SiC 10 was not being distributed by medium slurry for 3 wasted days. But once the slurry thickened enough about day 3 to lift the SiC 10 wear increased at a high rate. Like turning a switch on.
Solution was simple. Add enough clay(increased from 1 1/2 cups to 2 1/4 cups clay) at start, assure there is little rumbling sound from barrel. Which is what I did on the next batch of exact same dimension glass. Slurry thick from start. Yay, grind time was 5 days instead of 10 to 12 days. New recipe for SiC 10 is 2 1/4 cups clay for 5 day shaping time.
Beware of the "The no-grind coarse-grind start up syndrome." People new to tumbling deal with this issue regularly. Some experienced tumblers also. Especially those that have small barrels or slow spinning barrels.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Jan 24, 2020 7:11:49 GMT -5
Family fussing about the noisy rotary ? Thicken the slurry.
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