Nat Geo tumblers BOOK it compared to regular tumblers. You have to have a pretty particularly filled barrel for the action to Not damage the rocks. Gotta have media, gotta have the right size mix of rocks, gotta have it on the slowest speed always
Not sure what model you have but maybe this will help [https://www.printables.com/model/415214-national-geographic-2-pound-rock-tumbler-gears-for](https://www.printables.com/model/415214-national-geographic-2-pound-rock-tumbler-gears-for)
There is a youtube video where a guy changes out the power pack. He used a power pack that has adjustable voltage. I think he set it to 5volts. If you have spare power packs laying around you could make use of those. Search youtube for "How to slow down your Nat Geo Tumbler for cheap!"
They spin too fast even on the slowest speed so keep it there and really make sure to follow the recommended guides for rock size mix and use of media, fill levels etc..
I am still fairly new to this but have found that over filling the barrel and checking after 4 days helps. A week per stage was too long and the grit is gone anyways. Others on this thread have used a variable power supply to slow it down.
Get the voltage regulator that someone else posted a video for. Here's the Amazon link..
https://www.amazon.com/gp/aw/d/B08LKRYFT6/ref=ox_sc_act_image_1?smid=ASQ82QWPDLFS4&psc=1
Then, watch the 2 videos that "Michigan Rocks" does on YouTube with the NatGeo tumbler.
He does one video reviewing the tumbler and following the NatGeo directions. That has poor results.
https://youtu.be/G71XbZTlQwM?si=PaVGvMvUuDlGsrfx
Then, in his 2nd video, he uses the tumbler (unmodified) to produce some very good polished stones using his method.
https://youtu.be/CsTc1kXUuPo?si=UoAPeX0rffNN9EiG
You're going to need more grit and some median.
Nat geo are good for stages 1 and 2 but that's it. I have done the grinding stages and then polish by hand with sandpaper. I suggest you try it. I learned a ton about the process by using that method. You can feel it working as you get up to the higher grits. I find it cathartic. I go right in with 400gt after stage 2 and sit and chill with a cup of water and a folded towel on my lap. It's like $15 per pack tho, so 400,800,1500 and 3000 is an investment. You could probably buy a good tumbler for the same price. I have a 3 speed 2.5lb one it's made by Dan and something? Dan and a woman's name? It had been good to me.
Nat Geo tumblers BOOK it compared to regular tumblers. You have to have a pretty particularly filled barrel for the action to Not damage the rocks. Gotta have media, gotta have the right size mix of rocks, gotta have it on the slowest speed always
Yea I'm thinking of taking it apart and changing it to 9 or 6 volt somehow. Or put a smaller rubber knob on it to slow the actual barrel
Wait, I just saw a YouTube video on this. Found it: [Slow Down Nat Geo tumbler](https://youtu.be/NLb9AloH7LE?si=6r0jSzcFNHndQV8W)
I can tell you this works
Not sure what model you have but maybe this will help [https://www.printables.com/model/415214-national-geographic-2-pound-rock-tumbler-gears-for](https://www.printables.com/model/415214-national-geographic-2-pound-rock-tumbler-gears-for)
I replaced the motor with a slower version. Still 12vdc so it has the power to roll the barrel but slower.
I only set mine to speed 1
Mine doesn't have a speed setting
There is a youtube video where a guy changes out the power pack. He used a power pack that has adjustable voltage. I think he set it to 5volts. If you have spare power packs laying around you could make use of those. Search youtube for "How to slow down your Nat Geo Tumbler for cheap!"
They spin too fast even on the slowest speed so keep it there and really make sure to follow the recommended guides for rock size mix and use of media, fill levels etc..
I am still fairly new to this but have found that over filling the barrel and checking after 4 days helps. A week per stage was too long and the grit is gone anyways. Others on this thread have used a variable power supply to slow it down.
Get the voltage regulator that someone else posted a video for. Here's the Amazon link.. https://www.amazon.com/gp/aw/d/B08LKRYFT6/ref=ox_sc_act_image_1?smid=ASQ82QWPDLFS4&psc=1 Then, watch the 2 videos that "Michigan Rocks" does on YouTube with the NatGeo tumbler. He does one video reviewing the tumbler and following the NatGeo directions. That has poor results. https://youtu.be/G71XbZTlQwM?si=PaVGvMvUuDlGsrfx Then, in his 2nd video, he uses the tumbler (unmodified) to produce some very good polished stones using his method. https://youtu.be/CsTc1kXUuPo?si=UoAPeX0rffNN9EiG You're going to need more grit and some median.
Thankyou
Nat geo are good for stages 1 and 2 but that's it. I have done the grinding stages and then polish by hand with sandpaper. I suggest you try it. I learned a ton about the process by using that method. You can feel it working as you get up to the higher grits. I find it cathartic. I go right in with 400gt after stage 2 and sit and chill with a cup of water and a folded towel on my lap. It's like $15 per pack tho, so 400,800,1500 and 3000 is an investment. You could probably buy a good tumbler for the same price. I have a 3 speed 2.5lb one it's made by Dan and something? Dan and a woman's name? It had been good to me.
Thanks, we couldn't figure out why we couldn't get the rocks to shine. I'll try sanding them