Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Nov 26, 2015 13:55:21 GMT -5
Okay...I am new to this so be gentle. Tumbling my first batch of stones ever! Petosky stones from Michigan...
I have followed the instructions that came with my tumbler to the tee but I can not get a polish on my stones. I have bee tumbling them in the polish grit for about 15 days and they still have a faded grey color and no shine at all.
I have also purchased 2 more tubs so I can use one per grit. I cleaned up the stones from the previous tub which had been used for all 4 stages, and I put them in a brand new tub with the polish compound, tumbled them for about 10 days and no change...
what am I doing wrong?? they feel pretty smooth but just are not polishing at all...
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Post by captbob on Nov 26, 2015 14:16:39 GMT -5
We have a couple real experts here when it comes to Petosky stones, so you're in the right place! It's Thanksgiving, so an answer may not be immediate, but it sure is coming. Welcome to the forum! ETA: awesome avatar!
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Post by broseph82 on Nov 26, 2015 17:37:57 GMT -5
Okay...I am new to this so be gentle. Tumbling my first batch of stones ever! Petosky stones from Michigan... I have followed the instructions that came with my tumbler to the tee but I can not get a polish on my stones. I have bee tumbling them in the polish grit for about 15 days and they still have a faded grey color and no shine at all. I have also purchased 2 more tubs so I can use one per grit. I cleaned up the stones from the previous tub which had been used for all 4 stages, and I put them in a brand new tub with the polish compound, tumbled them for about 10 days and no change... what am I doing wrong?? they feel pretty smooth but just are not polishing at all... Jugglerguy has a whole thread (I think) on his secrets to tumbling petoskey stones
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Post by Jugglerguy on Nov 26, 2015 22:46:55 GMT -5
I've always heard that Petoskey stones are impossible to tumble. mibeachrocks and I figured it out though. I would not suggest doing them as my first rock tumble. There are lots of better rocks to tumble, including some from Lake Michigan. You might want to try Norwood chert if you live in that area. You could also buy some agates or jasper to tumble. If you really want to to tumble Petoskeys you can read about my efforts here. The more traditional way of polishing Petoskeys is by grinding them on a lapidary grinder of some sort. I use a flat lap for polishing Petoskeys. I can give you more details if you decide to try it this way. I've also polished one completely by hand using automotive wet/dry sandpaper. I bought a variety pack that included 320, 400, 600, and 800 grits. I finished up with aluminum oxide polish from The Rock Shed on an piece of denim from an old pair of jeans. I finished one side of a small rock in about an hour. Check it out here.There is a huge variety in Petoskey stones and some will not polish nearly as well as others.
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Nov 28, 2015 14:21:55 GMT -5
Your problem is that Petoskey stones are too soft to take a shine in a tumbler. They are made of calcium carbonate, which is Moh's hardness 3. Generally you want something at least Moh's hardness 5 to take a polish in a tumbler (like sodalite or obsidian, for example). Moh's 6 hardness (feldpars) will take a better shine, and all the quartz materials (petrified wood, agates, carnelian, etc) might take a long time to shape in coarse grind but will take a wonderful shine in the polish stage. Once you start getting harder than the quartz materials into say rough rubies at Moh's 9, then they are too darned hard and they take forever in each stage.
You can buy quartz materials at a rock shop or online, and in many cases you can just go out and collect them yourself as long as you aren't seeking out fancy agates and are happy with just shiny quartz pebbles.
As for Jugglerguy's hand-shining of a Petoskey stone, it looks like that ended up dull-shiny, which is much better than I would have expected you could achieve. Impressive. I have some travertine (mohs 3) that I tried in a tumbler years ago and it ended up shaped but dull -- I should try hand polishing those with Jugglerguy's method.
-Don
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Nov 30, 2015 21:32:06 GMT -5
I've always heard that Petoskey stones are impossible to tumble. mibeachrocks and I figured it out though. I would not suggest doing them as my first rock tumble. There are lots of better rocks to tumble, including some from Lake Michigan. You might want to try Norwood chert if you live in that area. You could also buy some agates or jasper to tumble. If you really want to to tumble Petoskeys you can read about my efforts here. The more traditional way of polishing Petoskeys is by grinding them on a lapidary grinder of some sort. I use a flat lap for polishing Petoskeys. I can give you more details if you decide to try it this way. I've also polished one completely by hand using automotive wet/dry sandpaper. I bought a variety pack that included 320, 400, 600, and 800 grits. I finished up with aluminum oxide polish from The Rock Shed on an piece of denim from an old pair of jeans. I finished one side of a small rock in about an hour. Check it out here.There is a huge variety in Petoskey stones and some will not polish nearly as well as others. Thank you all for the info... Unfortunately, the only reason I got in to this is to do Petosky stones sooooooo..... Jugglerguy, if you could help me out, I am not opposed to hand polishing. I have a beautiful bucket full of Petoskys and they are just beautiful when polished! I know it is doable since I have seen tons of them in shops, especially in the UP of Michigan. I would appreciate any help. What about spraying with clear gloss enamel (like Krylon)?
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Post by Jugglerguy on Nov 30, 2015 22:17:22 GMT -5
Please don't ever utter those words here again. That may be Petoskey stone blasphemy!
When you say "hand polishing", do you mean literally by hand or on a flat lap or other grinder? If you mean with sand paper and elbow grease, I think I explained it fairly well in that link. I'd be happy to answer questions if I wasn't clear.
Could you post pictures of the stones you have? Did you collect them yourself? Did you really see them in shops in the U.P., or were they in northern lower Michigan? Since they don't occur in the U.P., they're not as popular up there. They're more popular in shops along Lake Michigan up to Mackinaw.
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Post by captbob on Nov 30, 2015 22:40:12 GMT -5
A Petosky stone heretic!
Burn him!
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Nov 30, 2015 22:56:06 GMT -5
A Petosky stone heretic! Burn him! Oh my God! I have upset a "purist"!!
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Nov 30, 2015 23:00:22 GMT -5
Please don't ever utter those words here again. That may be Petoskey stone blasphemy! When you say "hand polishing", do you mean literally by hand or on a flat lap or other grinder? If you mean with sand paper and elbow grease, I think I explained it fairly well in that link. I'd be happy to answer questions if I wasn't clear. Could you post pictures of the stones you have? Did you collect them yourself? Did you really see them in shops in the U.P., or were they in northern lower Michigan? Since they don't occur in the U.P., they're not as popular up there. They're more popular in shops along Lake Michigan up to Mackinaw. I actually hunted them myself on the shore in Petosky... They are for sale all over Michigan, but yes, you are correct... mostly South of the bridge. I actually mined some copper up in the UP (with a metal detector). I soaked it in muriatic acid. Afterwards, before it got a chance to tarnish, I sprayed it with gloss Krylon. Preserved it perfectly and is still very shiny 5 years later. That is where my "evil, twisted thought" came from... I do not own any grinding equipment so I would have to hand-sand/polish.
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Dec 1, 2015 3:07:01 GMT -5
Well please do the hand polish on your Petoskey stones and show your results! I have no Petoskey stones myself, but I am interested because I have this travertine I tried to polish in a tumbler back in 2007. But it is a soft calcite stone, Moh's 3, same as Petoskeys, and I gave up on it because I couldn't get it to take any kind of shine back in 2007.
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Post by Jugglerguy on Dec 1, 2015 6:26:33 GMT -5
I have some copper from the Keweenaw Peninsula too. I wasn't sure what to do with it. I'll have to give the acid a try. rollingstone, if you have a vibe tumbler, give my dry method a try on those.
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Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
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Post by Tom on Dec 1, 2015 16:20:09 GMT -5
What about spraying with clear gloss enamel (like Krylon)?[/quote]
Hi There, welcome!
Never spray your rocks with gloss its considered cheating, evil even! Use a good quality wax on them instead, Ren wax comes to mind. This is what Juggler guy does to get such a nice shine.
*crawls back under rock and hides*
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Post by Jugglerguy on Dec 1, 2015 17:07:38 GMT -5
Hey! It is not!!!
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Post by Drummond Island Rocks on Dec 1, 2015 18:23:33 GMT -5
Ren wax comes to mind. This is what Juggler guy does to get such a nice shine. That explains so much I knew he was up to something. Chuck
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Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
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Post by Tom on Dec 1, 2015 18:36:32 GMT -5
Then you are pretty dang good:)
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Dec 1, 2015 20:21:12 GMT -5
I am going to use my tumbler to shape the Petoskys I have (I have a 5 gallon bucket full!). I have some ready and am going to try and sand them this weekend. Some of the specimens I found are just outstanding! I am planning another trip up North in the spring to see what the Winter waters have washed up!
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Post by Jugglerguy on Dec 1, 2015 22:42:35 GMT -5
I'd run them in 220 grit and possibly 500 grit before hand polishing. I've had better luck just going to 220. I never liked the way they look after 500 in a rotary tumbler. Use plenty of plastic pellets in the 220 stage and the 500 stage if you decide to try it.
We really need to see pictures of your rocks!
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Dec 2, 2015 10:14:53 GMT -5
I'm so new to this I don't even know what grits I am using! I bought 4 bags... one course, one fine, one pre-polish and one polish. I have had my first batch in polish for about 2 weeks. They are very smooth... just not shiny. I'll see if I can find out what grits I have. And I know you guys can recommend a good supplier of grits?
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Deano
off to a rocking start
Member since November 2015
Posts: 10
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Post by Deano on Dec 2, 2015 19:42:21 GMT -5
I finished my fist batch today using JugglerGuy's sandpaper recommendation... WOW! I got the exact results I was looking for! The ones I had tumbling in the polish, I just took out and started to polish them using the denim cloth like he recommended. Viola!!!
I took some pics and post later. BIG thanks guys!
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