bobmac
starting to shine!
Member since March 2008
Posts: 28
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Post by bobmac on Jun 29, 2009 17:50:12 GMT -5
Cleaning between grits (#500) I noticed black specks on many of the stones (beach). Tiny, they seem to get in almost invisible cracks. The black is impossible to rub off with water/fingers. There seemed to be black floating in the water as I hosed the bowls while removing stones for more individual attention. I removed all black stones in case I had a piece of coal or something in there and started fresh with #1000 prior to polish.
No good: still tiny black specks and floating stuff... not alot, but enough to ruin the batch. My bro-in-law (also UV 10) has had the same problem. He had dried out his bowl once and I figured he had compromised the finish somehow, but I've never had this happen before. I've run about a dozen batches from start to finish and thanks to good advice had great results... But this is worrisome. Any thoughts? Help appreciated greatly :help:
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Post by Bikerrandy on Jun 29, 2009 20:16:57 GMT -5
That's tiny particles of the bowl itself. Mine does the same thing, the old style bowls didn't do that. Anyhow, it doesn't seem to affect the results of my batches as long as I do a good burnish (Borax) stage after the 500 grit before moving the rocks to the polish-only bowl.
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bobmac
starting to shine!
Member since March 2008
Posts: 28
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Post by bobmac on Jun 30, 2009 6:07:00 GMT -5
Thanks, Randy... You were a great help when I was getting started... I guess I get a "polish only" bowl. Not what I wanted to hear, but it makes sense. One would think they could make a bowl that didn't deteriorate. I'll try the Borax post polish in hopes of removing specks.
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Post by NatureNut on Jun 30, 2009 7:50:25 GMT -5
Bob, I had them on a couple loads. If the burnish doesn't clean them up, you can run them over again for a day in 220 and prepolish, then run them a few days in polish, using plenty of plastic pellets for cushion. I had success the second time around. Good Luck. Jo
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bobmac
starting to shine!
Member since March 2008
Posts: 28
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Post by bobmac on Jun 30, 2009 11:29:28 GMT -5
Hey Jo... Ferocious looking Rockhound! Glad you said "a couple of loads" because that gives me hope that it won't happen all the time. Would you agree with Randy that it may be the bowl; or, are you thinking a "bad" rock? I'll be looking for the Rockhounds at Westminster. My best stones came from walking old, slow black lab, dearly missed.
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Post by Hard Rock Cafe on Jun 30, 2009 12:38:05 GMT -5
It's definitely the bowl. Mine (UV-18) does the same thing and I can see where the bowl is being worn away. The specks float, so they're not rock. I get them pretty much every run, but I've never gotten them embedded in rock.
I don't use plastic pellets, but maybe I should start...
Chuck
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Post by Bikerrandy on Jun 30, 2009 13:08:23 GMT -5
Chuck, I used to use plastic pellets until I discovered that I get the same results without them. Now of course, everything that goes into my tumbler is pre-shaped cuts, so there are no concave sides. In this case, pellets would benefit the load.
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Post by Hard Rock Cafe on Jun 30, 2009 19:28:52 GMT -5
I use ceramic pellets as filler when needed, but usually only after the coarse run. I was thinking of using the plastic pellets just to keep the bowl from wearing out. Maybe it doesn't make any difference...
Chuck
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