jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on May 19, 2020 4:43:59 GMT -5
Select tumble grade fracture free scraps from the local glass blower divided into -1/4" and +1/4" thicknesses.(pre-sorted) Nice hard, clear glass with few bubbles or defects. About 22 pounds all told. -1/4" shards tumbled separate from +1/4" chunkies chunkies hand picked. If divots or cracks were found glass nippers were used to finish splitting cracks or carving divot making edges. shards ~SiC 10 and red clay slurry thickener. It took 3 barrels. Glass loaded to 3/4 fill. Add water, SiC 10 and clay. Clay doses were 1 cup small barrel, 1.75 cups medium and 2 cups large. Let er rip !(fat barrel used to reach 'slightly defective' bearing in end roller upper right lol) Back shaft at 74 rpm, front shaft at 34 rpm. Size of glass was picked for 50% weight reduction, so these will get a serious beat down. And a week in SiC 60 must be calculated in for ~50% weight loss(a nice jewelry size). SiC 60 will prep surface for SiC 500 run in vibe.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on May 19, 2020 5:19:52 GMT -5
Some would say SiC 10 at 74 rpm is abusive lol. Believe it, mother nature beats rocks down a lot more than these tumblers. Just avoid BRUISES. No issue with treating rocks or glass with a portion of the abuse mother nature deals out as long as you use finer abrasives(in this case SiC 60) to remove the scratches imparted by the SiC 10. IMO tumblers do not use enough artillery to shape rocks faster(3 to 4 month shaping times ?#$@#, please). IMO rotary tumblers should have been designed to handle coarser silicon carbide and higher shaping speeds. Not to mention saving money on raw silicon carbide. SiC 60-80-60/90 and other graded silicon carbides is only expensive, such precision graded abrasive is unnecessary for the totally crude process of shaping rocks. I think the tumbling hobby would have been much more popular if it did not take so long to shape rocks.
rant done
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on May 19, 2020 22:25:21 GMT -5
Lots of big talk. Check out results. After 2.5 days at 74 rpm and a heavy dose of 1 cup raw SiC per 6 pounds glass. About the same as 2 weeks with conventional coarse SiC and +/- 30 rpm speeds. Some of the denser SiC 10+ left over, note smoothed faces on it suggesting some serious abrasion. Not going to do an SiC 60 run, instead going straight to vibe using SiC 500 thinking the SiC 500 will remove the rough surface of the SiC 10.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on May 19, 2020 22:49:31 GMT -5
Blows my mind how quickly you can shape things. They're looking good! One day, when I grow up, I want to tumble like you!
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
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Post by jamesp on May 19, 2020 23:08:15 GMT -5
Blows my mind how quickly you can shape things. They're looking good! One day, when I grow up, I want to tumble like you! Lol, a rugged rag tag 2 speed tumbler, wear resistant barrels and el cheapo raw silicon carbide is all it takes Ben.
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