|
Post by Jugglerguy on Mar 26, 2016 20:29:59 GMT -5
I've been tumbling a lot of Petoskey stones lately. My method is to rotary tumble in a six pound barrel with double water (2 cups) and one tablespoon of 80 grit SC. I do a clean out twice a week. The slurry is very thick and the rocks shape up quickly. Then I do three days with one tablespoon of 220 and plastic pellets in a rotary tumbler. I'm not sure the plastic pellets are necessary. Then it's on to the Lot-O. I run them for two days in 500 grit with corn cob media. I originally used 1 tablespoon of 500 AO. I occasionally recharge with more 500, but I continue to reuse the same corn cob. No problems up to this point. The polish stage is where I have problems, but I know how to fix the problem now. What I can't figure out is why it's happening. I do this stage just like the one before. I run them in the Lot-O with dry corn cob and AO polish. The first time, it works great. The next time I run a batch in the same barrel, the rocks don't get quite as shiny. The third run they get coated in a white film that is fairly hard to remove. I have to scrub it off each rock individually with a toothbrush. The rock on the bottom left shows a problem rock. The first time this happened, I was running black fossils like the ones in the picture. At first I thought the different rocks were the problem, but the same thing happens with a batch of just Petoskey stones. Eventually I figured out that I have to clean the barrel between each batch. The inside of the barrel gets coated in white. I run some ceramic and borax to clean the barrel and the next batch turns out great again. So I know how to prevent the problem, but I don't know what causes it. Any ideas what might cause this white coating?
|
|
johnnymac1969
starting to spend too much on rocks
I Like A Rolling Stone
Member since January 2016
Posts: 139
|
Post by johnnymac1969 on Mar 27, 2016 8:18:02 GMT -5
I blame Obama… or Trump
|
|
panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
|
Post by panamark on Mar 27, 2016 9:18:05 GMT -5
Rob, could it be some oil/tar coming out of the rocks? I know some of those type smell pretty oily when cut.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,179
|
Post by jamesp on Mar 27, 2016 9:21:49 GMT -5
I used wet lime in the rotary for a thickener and it was probably to wet to make a coating. Since the vibe is not as wet(assuming) it must make a paste that sticks to the barrel.
My coral has that white/soft limestone layer on it but it always gets ground off in the wet rotary. When I put a lot of coral in the rotary with a white layer on it the slurry gets super thick in a few days. I let it get too thick once and it made lime goop that was really hard to wash off. I just added a lot of water and tumbled it off. Looks your tumbling it off with detergent and media/rocks is best way to clean.
Really cool black coral, don't care for the ghost.
|
|
Fossilman
Cave Dweller
Member since January 2009
Posts: 20,687
|
Post by Fossilman on Mar 27, 2016 9:32:49 GMT -5
Yes,some fossils bleed out,because of the oil content in the rock (Material)....Just have to scrub them as you see fit....
|
|
|
Post by Jugglerguy on Mar 27, 2016 10:06:09 GMT -5
The black fossils definitely have oil in them. I can smell it. That was my fisrt thought because it first happened after running a batch of the black stuff. But I can then use that same media that caused the problem, but in a clean barrel and there's no problem. I tried brand new media and had the same results without ever having the black fossils in it.
My best guess is that with a clean barrel, the white coating sticks to the barrel easier than it does to the rocks. So whatever that substance is can stick to the clean barrel, but when the barrel gets fully coated, it can no longer stick there and goes to the next easiest thing to stick to, which is the rocks.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,179
|
Post by jamesp on Mar 27, 2016 10:26:32 GMT -5
Oh, this is happening during dry tumble, when I dry tumbled in the Viking with polish I had a serious coating. Pressure washer to remove. Must be the polish concreting. The 500 did not do it so much, but the polish did.
|
|
|
Post by Jugglerguy on Mar 27, 2016 16:21:19 GMT -5
Same here. The 500 doesn't do it, but the polish does. Strange.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 27, 2016 16:36:46 GMT -5
Polish dry, may be getting hot.
Not truly helpful, but food for thought.
|
|
sschus87
starting to shine!
Member since November 2015
Posts: 49
|
Post by sschus87 on Mar 27, 2016 16:44:27 GMT -5
I run them for two days in 500 grit with corn cob media. Any chance you could post a picture of what this looks like? The corn cob I mean. Size is what I am wondering about. I have been using pistachio shells in my polish and they seem to be working well. They have held up for a couple of months with no evidence of wearing down. Plus, I love pistachios, so I can justify eating them because I need to save up the shells... Thanks---Steve
|
|
|
Post by Jugglerguy on Mar 27, 2016 16:54:45 GMT -5
Polish dry, may be getting hot. Not truly helpful, but food for thought. Nope, nothing is getting hot. It's just dry stuff running in my Lot-O.
|
|
|
Post by Jugglerguy on Mar 27, 2016 16:57:24 GMT -5
I run them for two days in 500 grit with corn cob media. Any chance you could post a picture of what this looks like? The corn cob I mean. Size is what I am wondering about. I have been using pistachio shells in my polish and they seem to be working well. They have held up for a couple of months with no evidence of wearing down. Plus, I love pistachios, so I can justify eating them because I need to save up the shells... Thanks---Steve Sure, here you go: On the left is corn cob media from The Rock Shed. It's ground very small, maybe 1/16 of an inch. On the right is Hartz brand animal bedding from Walmart. I ran a couple batches in this and it seemed to work fine too. The Walmart stuff is much cheaper and doesn't have to be shipped, so I'd try it first if you're planning on dry tumbling.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 27, 2016 17:24:52 GMT -5
Polish dry, may be getting hot. Not truly helpful, but food for thought. Nope, nothing is getting hot. It's just dry stuff running in my Lot-O. How do you know that? Ever held a cab against a relatively dry polishing buff with bare fingers? Can get hot enough to not be handled safely. The Polish makes brazolions of tiny cuts in the stone. Each generate heat. Adds up to significant heat. I have had spheres in Polish on a sphere machine so hot I had to let them cool down. With water it took 15 minutes. Why lotto different?
|
|
|
Post by Jugglerguy on Mar 27, 2016 17:28:42 GMT -5
The media in the Lot-O is not moving as fast as a buffing wheel. It's just gently rolling. I regularly stick my fingers in to grab rocks to check on them. They're room temperature. I have experienced some heat on a flat lap with polish, but this isn't anything like that.
|
|
SirRoxalot
freely admits to licking rocks
Member since October 2003
Posts: 790
|
Post by SirRoxalot on Mar 28, 2016 16:35:36 GMT -5
It's a compacted coating of polish and rock dust, would be my guess. Tumbling with water would keep it from sticking, but then you'll have problems with your media, unless you want to make moonshine while you tumble, lol. So, you could clean the barrel with a mild acid, but not the rocks, as they'd be dulled. You could try more media, less rock, and/or less grit, to make less dust. Try soaking the rocks in a de-greaser like acetone to pull out the oil, before putting them in? Try adding a slippery, non-abrasive powder, like talcum powder, or powdered soap, or a hard powdered wax, the stuff they use on shuffleboard courts, to reduce the stickiness? I suspect much of the oil is in the black shale surrounding the fossils, so maybe add more "regular" Petoskey stones to reduce the oil per load? Might take some time to solve.
Keep us posted, I love hearing about your work with the soft stuff. Your photo is amazing; we've yet to find anything like that on this side of Lk. Huron, though we do have a couple other interesting corals to be found along with the Petoskeys. Very nifty.
|
|
|
Post by Jugglerguy on Mar 28, 2016 23:46:04 GMT -5
I'll be posting some more of the black ones in a few minutes, so look for the thread.
I know exactly how to prevent this, I'm just unsure of why it works. Cleaning the barrel between loads fixes it. It happens with 100% Petoskeys or a mix with other fossils. By washing between loads, I can also do a batch of 100% black fossils without a problem. I agree that it's either rock dust, corn dust, polish or a combination of all three. It's weird that there's no problem with 500 grit even with a barrel that is completely coated in white.
|
|
|
Post by aliengreensoul on Feb 23, 2020 6:47:14 GMT -5
Has anybody ever figured this problem out? The same thing happened when I dry tumbled fluorite in 1000 AO a year ago I used cheap corn cob bedding from Walmart and gave up after seeing the results and set the stone aside it still sits to this day looking worse then it did in rough state all bruised up and dull even after I burnished it to remove dust weather corn or aluminum I was wondering if regular dried (Not instant) rice would work in ground corncobs place?
|
|
|
Post by parfive on Feb 23, 2020 13:08:48 GMT -5
aliengreensoul Just for the hell of it, try buffing a piece of fluorite by hand on a scrap of denim, dry, with a little AO polish sprinkled on there. Should help it look a wee bit better.
|
|
sheriam
starting to shine!
Member since December 2019
Posts: 34
|
Post by sheriam on Feb 24, 2020 7:15:42 GMT -5
Wow, these are so beautiful!
|
|
|
Post by Jugglerguy on Feb 24, 2020 8:41:44 GMT -5
Has anybody ever figured this problem out? The same thing happened when I dry tumbled fluorite in 1000 AO a year ago I used cheap corn cob bedding from Walmart and gave up after seeing the results and set the stone aside it still sits to this day looking worse then it did in rough state all bruised up and dull even after I burnished it to remove dust weather corn or aluminum I was wondering if regular dried (Not instant) rice would work in ground corncobs place? I have not figured out what's going on here. I decided that it was those black rocks that contain some oil. That doesn't fit with your fluorite problem though. I do know that cleaning the inside of the barrel really well fixes it for a time.
|
|