stellarblue
off to a rocking start
Member since January 2024
Posts: 6 
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Post by stellarblue on Jan 14, 2024 15:07:34 GMT -5
Greetings from the PNW!
I'm new, and not of my own accord - my 4.5 yo saw some rock tumbling videos on tiktok (#satisfying) and wanted to join the fun. Obviously, at 4.5, the details are not important to this hobby, but the rock collecting and pouring, dumping, and setting the tumbler are peak fun. This is where I come in. Or should have when I found out this was going to be gifted to my kiddo. HA!
After some brief tiktok reviews we went with the NatGeo tumbler, chucked their grits and got some Polly Plastics, but now that I'm finding out the things I never knew I should consider, I am realizing I may have taken advice from the wrong crowd on a few things. Most of our rocks (outside of what was included in the NatGeo kit) are saltwater beach finds, and are turning out better than expected. The NatGeo rocks were virtually pea gravel after 3 days in PP stage 1; cue Parent#2 and I panicking - we switched to beach rocks at that point. I then took more advice from yet another what now seems to be a less knowledgable source and we started polishing last night (end of day 15 total). Then I doom-scrolled through rock tumbling reddit
Now we get to the questions I have being ever so slightly more educated/having had a bare minimum of experience:
1. I need a concrete guide on how I'm supposed to tell when to change to the next grit. Literally everything I've found is either "x-x days" with a WIDE range, or "when it looks ready," neither of which are remotely helpful to me as a complete noob. We have a small magnifying/microscope situation and I've seen the same "raw" washed beach rocks and day 5 of stage 1, and could appreciate a difference. I'm not really sure I saw that much of a difference at the end of 5 days in stage 2, and definitely not after 5 more days in stage 3, they all just look pretty smooth to me.
2a. How do I even begin to determine softness of rocks? Is it really that important? Can I not just gather from the same beach and call it good? Cause they tumbled there for their first few millennia or so, right? HA! We're not looking to spend a whole lot of money on ordering rocks to tumble at this point - its a fun thing for my kid from collecting to all the tumbling stages.
2b. I have zero clue in figuring out how to ID rock outside of basalt, pumice, and a few crystal-y things like amethyst and rose quartz. I've read descriptions and when I finally think I have it, the actual type of rock was not even in my top 5 guesses. And don't get me started on how confusing the pictures are. I'm a biology person, this rock stuff is difficult!
I appreciate the patience to read this far, and understand how monotonous it can be to repeat what feels like the most basic of information. I am grateful for any responses - even just links - to help my kiddo have a positive experience with this new hobby (ok, its growing on me too).
Thank you all!
StellarBlue
Thanks!
Noob StellarBlue
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stefan
Cave Dweller 
Member since January 2005
Posts: 14,113
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Post by stefan on Jan 14, 2024 15:22:50 GMT -5
Welcome. The short and sweet of grit changes. After the course grit, the goal is to remove the scratches left by the last grit (think sandpaper and wood- the finer paper to put a smoother finish). The reason you get the XX days is that is what works. THe Nat. Geo tumbler is a dirty little catch 22. It works real fast in the course stages (Stage 1 and 2) but then tends to beat the daylights out of the rock in the later stages (too fast even on the slowest speed). As for Polly Plastics, well the grit is good, the polish is not real polish and is like 1200 grit and won't really shine the rocks. Most of us use Aluminium Oxide polish (which I'd anywhere from 8000 grit and finer). There are ways to slow down the tumbler that involve changing the AC adapter from a 12 volt to a 7.5 volt.
As for rock ID, Well you want to tumble similar hardness stones (usually from Mohs 5.5 to 7) Best way to tell is to try (carefully) to scratch a knife blade (a real scratch, not a line of chalky dust). If it truly scratches a knife blade (or any steel) it is probably good to tumble.
As for length of cycle, usually a week in each stage after course is what most people do. I run 2 weeks because I have 8 machines running so I split them into 2 groups and check each group every other week.
ALSO MOST IMPORTANT DO NOT DUMP THE ROCK SLURRY DOWN THE DRAIN!!!! You will make your local plumber very rich if you do.
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stellarblue
off to a rocking start
Member since January 2024
Posts: 6
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Post by stellarblue on Jan 14, 2024 15:32:55 GMT -5
Welcome. The short and sweet of grit changes. After the course grit, the goal is to remove the scratches left by the last grit (think sandpaper and wood- the finer paper to put a smoother finish). The reason you get the XX days is that is what works. THe Nat. Geo tumbler is a dirty little catch 22. It works real fast in the course stages (Stage 1 and 2) but then tends to beat the daylights out of the rock in the later stages (too fast even on the slowest speed). As for Polly Plastics, well the grit is good, the polish is not real polish and is like 1200 grit and won't really shine the rocks. Most of us use Aluminium Oxide polish (which I'd anywhere from 8000 grit and finer). There are ways to slow down the tumbler that involve changing the AC adapter from a 12 volt to a 7.5 volt. As for rock ID, Well you want to tumble similar hardness stones (usually from Mohs 5.5 to 7) Best way to tell is to try (carefully) to scratch a knife blade (a real scratch, not a line of chalky dust). If it truly scratches a knife blade (or any steel) it is probably good to tumble. As for length of cycle, usually a week in each stage after course is what most people do. I run 2 weeks because I have 8 machines running so I split them into 2 groups and check each group every other week. ALSO MOST IMPORTANT DO NOT DUMP THE ROCK SLURRY DOWN THE DRAIN!!!! You will make your local plumber very rich if you do. Excellent short and sweet! I'll let the 1200 Al2O3 tumble while I find a significantly more fine grit.  I did learn that important point, to not dump slurry down the drain, from the seemingly less knowledgable sources, but I very much appreciate the warning. TYVM! |
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adam5
starting to spend too much on rocks
Member since August 2023
Posts: 153
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Post by adam5 on Jan 14, 2024 16:26:03 GMT -5
Stefan is probably the most experienced tumbler active on this forum, so I would take note of his recommendations  This is my input: 1. I need a concrete guide on how I'm supposed to tell when to change to the next grit. Literally everything I've found is either "x-x days" with a WIDE range, or "when it looks ready," neither of which are remotely helpful to me as a complete noob. We have a small magnifying/microscope situation and I've seen the same "raw" washed beach rocks and day 5 of stage 1, and could appreciate a difference. I'm not really sure I saw that much of a difference at the end of 5 days in stage 2, and definitely not after 5 more days in stage 3, they all just look pretty smooth to me.Assuming that the barrel is being filled properly (2/3 to 3/4 full with different sizes of rocks, water to just below top layer of rocks), the time needed in the 1st stage (coarse grind) depends on the initial condition of the rocks, the hardness of the rocks, and the tumbler speed. Given the speed of the Nat Geo tumbler and the rocks you are using, 1 to 2 five day rounds of stage 1 followed by 1 round each of stage 2 and 3 will probably have the beach rocks prepped for polishing. But getting a good polish on the those rocks (keep in mind that some of them may not take on a good polished finish) will require a little more work and investment. I recommend watching these two videos that forum member Jugglerguy has on his YouTube channel: 2a. How do I even begin to determine softness of rocks? Is it really that important? Can I not just gather from the same beach and call it good? Cause they tumbled there for their first few millennia or so, right? HA! We're not looking to spend a whole lot of money on ordering rocks to tumble at this point - its a fun thing for my kid from collecting to all the tumbling stages.In my opinion it does not matter unless this goes beyond just having some fun with your kid and turns into a hobby. Which has happened quite often. 2b. I have zero clue in figuring out how to ID rock outside of basalt, pumice, and a few crystal-y things like amethyst and rose quartz. I've read descriptions and when I finally think I have it, the actual type of rock was not even in my top 5 guesses. And don't get me started on how confusing the pictures are. I'm a biology person, this rock stuff is difficult!
There are some very knowledgeable folks on this forum who can help out with identification. I am not one of them  By the way, if you need to reduce the speed of the tumbler, you can get this variable voltage power supply to decrease the voltage being supplied to the tumbler, which will in turn slow the tumbler down. This may be helpful during the polish stages. |
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Post by chris1956 on Jan 14, 2024 16:27:36 GMT -5
Welcome from Missouri. Identifying rocks from a beach is hard to do. Use the scratch test like stefan suggested and try to keep track of what you put into your tumbler and what comes out. You will figure out pretty quick what is junk. Although I still pick up a lot of junk that when I get it home I look and wonder why I picked it up.  |
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stellarblue
off to a rocking start
Member since January 2024
Posts: 6
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Post by stellarblue on Jan 14, 2024 16:58:03 GMT -5
Stefan is probably the most experienced tumbler active on this forum, so I would take note of his recommendations  This is my input: 1. I need a concrete guide on how I'm supposed to tell when to change to the next grit. Literally everything I've found is either "x-x days" with a WIDE range, or "when it looks ready," neither of which are remotely helpful to me as a complete noob. We have a small magnifying/microscope situation and I've seen the same "raw" washed beach rocks and day 5 of stage 1, and could appreciate a difference. I'm not really sure I saw that much of a difference at the end of 5 days in stage 2, and definitely not after 5 more days in stage 3, they all just look pretty smooth to me.Assuming that the barrel is being filled properly (2/3 to 3/4 full with different sizes of rocks, water to just below top layer of rocks), the time needed in the 1st stage (coarse grind) depends on the initial condition of the rocks, the hardness of the rocks, and the tumbler speed. Given the speed of the Nat Geo tumbler and the rocks you are using, 1 to 2 five day rounds of stage 1 followed by 1 round each of stage 2 and 3 will probably have the beach rocks prepped for polishing. But getting a good polish on the those rocks (keep in mind that some of them may not take on a good polished finish) will require a little more work and investment. I recommend watching these two videos that forum member Jugglerguy has on his YouTube channel: 2a. How do I even begin to determine softness of rocks? Is it really that important? Can I not just gather from the same beach and call it good? Cause they tumbled there for their first few millennia or so, right? HA! We're not looking to spend a whole lot of money on ordering rocks to tumble at this point - its a fun thing for my kid from collecting to all the tumbling stages.In my opinion it does not matter unless this goes beyond just having some fun with your kid and turns into a hobby. Which has happened quite often. 2b. I have zero clue in figuring out how to ID rock outside of basalt, pumice, and a few crystal-y things like amethyst and rose quartz. I've read descriptions and when I finally think I have it, the actual type of rock was not even in my top 5 guesses. And don't get me started on how confusing the pictures are. I'm a biology person, this rock stuff is difficult!
There are some very knowledgeable folks on this forum who can help out with identification. I am not one of them  By the way, if you need to reduce the speed of the tumbler, you can get this variable voltage power supply to decrease the voltage being supplied to the tumbler, which will in turn slow the tumbler down. This may be helpful during the polish stages. Its always nice to hear who the experts are as soon as I walk in a room, thanks for that! Its also both surprising and good to hear I'm not that far off from what your expectations for my situation would be with our one round of beach rocks!  I'll check out the videos when I have a bit more uninterrupted time tonight. Also excellent to hear that I don't need to learn much about rocks to get going with this new adventure - it seems to be an unspoken rule that I should be able to identify what I'm tumbling. Def checking out the power supply adapter, I was surprised at the clip the NG tumbler took off at, and it didn't occur to me that the speed of tumbling, within reason, would make a big difference. Thanks so much! |
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stellarblue
off to a rocking start
Member since January 2024
Posts: 6
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Post by stellarblue on Jan 14, 2024 17:00:59 GMT -5
Welcome from Missouri. Identifying rocks from a beach is hard to do. Use the scratch test like stefan suggested and try to keep track of what you put into your tumbler and what comes out. You will figure out pretty quick what is junk. Although I still pick up a lot of junk that when I get it home I look and wonder why I picked it up.  Excellent suggestions! With a 4.5 year-old doing a lot of the picking up, I can very much get behind the last sentence HA! Thank you! |
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wseaton
starting to shine!
Member since January 2024
Posts: 30
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Post by wseaton on Jan 14, 2024 19:36:14 GMT -5
The reason beach rocks / landscapes work better is because they are already weathered and quite often I can skip stage 1. Stage 2, which is 120/220 silicon carbide is pretty darn abrasive and found it can smooth out quite a bit on it's own. Stage 1 is oh so dependant on many factors. A rock may otherwise be perfectly smooth and ready for stage 2 from the beach, but it has a small 1/4 dent in it. Does that rock need weeks in stage 1 to remove that dent, or can you just ignore that little imperfection and go to stage 2? Entirely subjective.
Another advantage with beach rocks is being out in the environment the really soft rocks have mostly long since turned to sand, so what you pick up is typically more consistent in terms of hardness. Petoskey being an exception and obviously granite is quirky, but I can tumble it. The trick is to do this soft stones by themselves.
Stage 1 can take weeks, or you can skip it entirely if the rock is already pretty smoot, and or you aren't obswssed about grinding out it's imperfections. It's by far the most variable ridden step.
Stages 2 and 3 are easy in my book. Don't pack too many large rocks in the tumbler, use a mix of smaller sizes so things roll smoothly, and a heaping tablespoon of silicon carbide in stage 2 should be turned to grey pudding and used in 3, maybe 4 day max. How long it takes stage 2 is a pretty good indicator of how long stage 3 will take. Once rocks take on a little bit of sheen at the end of stage 3 you know you are ready for polish.
Also, the polish sold in hobby kits is trash. Poly Polish is trash. It's like 1200 AO, and it wont do much in a tumbler. You need the dedicated polish from rock shed, etc to get a nice polish. Critical point: the other grits in hobby kits is fine. Don't toss it. It's just the polish that doesn't work.
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stellarblue
off to a rocking start
Member since January 2024
Posts: 6
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Post by stellarblue on Jan 17, 2024 22:13:57 GMT -5
The reason beach rocks / landscapes work better is because they are already weathered and quite often I can skip stage 1. Stage 2, which is 120/220 silicon carbide is pretty darn abrasive and found it can smooth out quite a bit on it's own. Stage 1 is oh so dependant on many factors. A rock may otherwise be perfectly smooth and ready for stage 2 from the beach, but it has a small 1/4 dent in it. Does that rock need weeks in stage 1 to remove that dent, or can you just ignore that little imperfection and go to stage 2? Entirely subjective. Another advantage with beach rocks is being out in the environment the really soft rocks have mostly long since turned to sand, so what you pick up is typically more consistent in terms of hardness. Petoskey being an exception and obviously granite is quirky, but I can tumble it. The trick is to do this soft stones by themselves. Stage 1 can take weeks, or you can skip it entirely if the rock is already pretty smoot, and or you aren't obswssed about grinding out it's imperfections. It's by far the most variable ridden step. Stages 2 and 3 are easy in my book. Don't pack too many large rocks in the tumbler, use a mix of smaller sizes so things roll smoothly, and a heaping tablespoon of silicon carbide in stage 2 should be turned to grey pudding and used in 3, maybe 4 day max. How long it takes stage 2 is a pretty good indicator of how long stage 3 will take. Once rocks take on a little bit of sheen at the end of stage 3 you know you are ready for polish. Also, the polish sold in hobby kits is trash. Poly Polish is trash. It's like 1200 AO, and it wont do much in a tumbler. You need the dedicated polish from rock shed, etc to get a nice polish. Critical point: the other grits in hobby kits is fine. Don't toss it. It's just the polish that doesn't work. Awesome. Thank you for the explanation! |
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Post by Mel on Jan 24, 2024 11:57:07 GMT -5
I hate to "toot my horn" but I've got a couple posts about starting tumbling here that will probably serve you well. RTH is a fantastic group and you will always get good information! |
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I'll check out the videos when I have a bit more uninterrupted time tonight. 
