rockin50
off to a rocking start
Rock Tumbling - It's worth the wait!
Member since February 2009
Posts: 24
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Post by rockin50 on Mar 13, 2009 20:49:16 GMT -5
Hello All, Well after waiting patiently for my first batch of rocks to get done, I was a bit disappointed when I took them out. I purchased a 7# bag of rocks on eBay and they (like I thought) were not the greatest. The auction said there was some agates, jaspers, quartz & granite. What I found was their inability to gloss up. Some did better than others. And some others didn't even shine at all. So, I thought maybe it was something I did. Each cycle ran no less than 7 days. The first two grinding stages went well. Nice rounding smooth rocks. The polishing phase was a disaster. Could it be bad polish and pre-polish ? I am doing another batch now of Petrified Wood and will use material from a reputable seller. The PP is 500/600 grade silicone grit and the Polish is Aluminum Oxide. The first batch polish was almost orange color. (not sure what that was). Now one final question, I use a full bag (4 oz bag) of pellets (each separate pellets) for both the PP stage and polish stage. Was that too many pellets to use and would that make a difference in the polishing? HOW MANY PELLETS do most people use in a 3 lb Thumbler? Thanks again for helping me out. I am hoping better for this next batch. Regards, Lou  |
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Sabre52
Cave Dweller 
Me and my gal, Rosie
Member since August 2005
Posts: 20,496
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Post by Sabre52 on Mar 13, 2009 21:26:20 GMT -5
Lou: I sometimes use the 500/600 grit as a pre prepolish ( 3rd step) in a five stage process for something like obsidian or tigereye. I think tripoi pre polish is more in the 1300/1500 range so maybe running the 500/600 only seven days does not allow it to break down to a proper prepolish. After prepolish with tripoli, my stones look almost totally polished and I run prepolish 15 days. Longer the run, more the prepolish breaks down. Pet wood should give you a really dynamite polish with little effort but you might want to try tripoli as a prepolish. If you run 110/220 fine grind for 15 days, it'll break down and you can skip the 500/600 on hard materials like pet wood....Mel
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darrad
fully equipped rock polisher
Member since September 2006
Posts: 1,636
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Post by darrad on Mar 13, 2009 22:26:57 GMT -5
Maybe you got some softer stuff that would not polish no mater what you did. If they shaped up after only 2 cycles (If I'm reading correctly) I am guessing it was soft stuff.
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rockin50
off to a rocking start
Rock Tumbling - It's worth the wait!
Member since February 2009
Posts: 24
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Post by rockin50 on Mar 14, 2009 9:17:41 GMT -5
OK , use the Tripoli 1300/1500 for two weeks? Question: the higher the number the finer the grain?
Also, if I used the 500/600 and extend the run cycle, does that allow the grain to reduce down to the 1300/1500 range (like tripoli?)
Learning, Learning, Learning ... You guys are good!!
Thanks!
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,496
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Post by Sabre52 on Mar 14, 2009 9:34:29 GMT -5
Yep, I run longer cycles in the last three stages to let the grit break down further. Yep, higher the number finer the grains. Yep, if you run 500/600 longer it will break down into smaller sized particles....Mel
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Post by MyNewHobby on Mar 14, 2009 17:15:55 GMT -5
Pellet use seems to be a matter of personal preference.
I have a twin Lortone 3 lb barrels ...
I am learning that (with me) if I have a really rough batch (mohs 6.5 and higher) to begin with, I would prefer the rocks to smack around. For me, I have seen where points and grossly ragged edges get snapped off or smoothed out much better without the pellets.
Softer stuff ... I start using pellets. I use approximately equal amounts of grit and pellets.
Stages 2-4 I always add pellets.
This is just me ...
Thanks for posting this ... I always learn something more about fine tuning my processes.
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rockin50
off to a rocking start
Rock Tumbling - It's worth the wait!
Member since February 2009
Posts: 24
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Post by rockin50 on Mar 14, 2009 19:00:11 GMT -5
Great ...
That would generally be (4) tablespoons for my 3lb'er. I kinda thought I was using too many (overkill maybe??) Thanks!
Also looking to buy a 3B (Lortone) as my next tumbler. Yup! there are many seasoned tumblers here. Lots of good suggestions.
Always learning ... ;D
Lou
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DeanW
has rocks in the head
Member since December 2007
Posts: 721
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Post by DeanW on Mar 16, 2009 9:32:39 GMT -5
Lou,
I'm not so sure that granite is good for tumbling mixed with other materials, sounds like it would crumble too easily (at least the 'natural' granite I've seen seems to crumbly) and thus contaminate your load. Nicely polished granite for counter-tops and such has been treated with a sealer/stabilizer and doesn't have quite the same problem.
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rockin50
off to a rocking start
Rock Tumbling - It's worth the wait!
Member since February 2009
Posts: 24
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Post by rockin50 on Mar 16, 2009 21:10:07 GMT -5
Yep, whole batch of rough was a dissapointment. Maybe six out of the whole batch polished nicely. I consider this a learning experience and will be more picky next time I purchase. I used the rest of the rocks and put them around my mailbox outside LOL!! Just did a 3 day check on the Pet Wood. Slurry seems a bit thin so far. Not sure why, I do see some obvious rounding on some stones and I will check again at the 7 day mark and will re-charge at that time. I am thinking to leave them in for 14 days total on 60/90 grit. Take Care ....
Lou
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rockin50
off to a rocking start
Rock Tumbling - It's worth the wait!
Member since February 2009
Posts: 24
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Post by rockin50 on Mar 26, 2009 21:13:09 GMT -5
I just thought of something, I just reviewed the sellers photo from the rocks and batch I purchased on ebay. I looks like she sold me Tripoli as the final polish. Could this be the reason for the dull shine? (This stage tumbled only 7 days)
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Post by johnjsgems on Mar 26, 2009 21:33:43 GMT -5
I think you got it. Tripoli is a prepolish. The 500/600 "prepolish" is really a fine sanding prior to polish which unless it runs a long time is not a prepolish. It is prior to polish so does get labeled as a pre-polish step quite often. Technically all grit steps before polish are "pre-polish". If you got some actual polish try that and see what happens. The granite near where we used to live (common river rocks) polished up great because of high quartz content. I never tumbled any but saw some interesting spheres made out of it.
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