NATIONAL GEOGRAPHIC Rock Tumbler Kit – 1.36 kg Extra Large

The product is good quality and great value. Kids (yes, and me) are enjoying learning about the rocks so is an educational journey too. Do note that tumbling rocks takes a loooooong time, perhaps a month if you do a basic job. If you want perfect polished stones it will take 3-4 months and more grit than is provided in the kit will be needed. Therefore, this product is best for kids who have patience.
However, the reason for the high rating was for the exceptional customer service received. The kit arrived with an item missing but the customer service representatives were generous with their time finding options to make up for the missing item.

We’ve processed about 7 batches of rocks with great success . After using the included materials, We’ve bought aftermarket polishing material and aftermarket bands. The bands wear out and we were having issues replacing with the included ones. Have had great success with aftermarke

I bought the tumbler to smooth the sharp edges of seaglass that I referred to as Craft grade, the tumbler worked like a charm on my test run! I throw in ugly glass and ceramic pieces….what came out of the tumbler amazed me. I let it run with the 60/90 grit for 3 days, next time I’ll check it daily as the pieces were smoother than I wanted. I just put in another load of ugly glass, can’t wait to turn it into faux seaglass gems that I’ll use in my crafts.

Aus anderen Rezensionen war ich bereits vorgewarnt, dass der Stromstecker fr britische Steckdosen ausgelegt ist. Man braucht also noch einen Adapter um es in Betrieb zu nehmen. Die Trommel luft rund und poliert die Steine auch richtig schn. Es wird zwar in der Beschreibung darauf hingewiesen, dass man Steine von hnlichem Hrtegrad nehmen soll aber in dem Startkit sind sehr unterschiedliche Steine drin. Die Roten haben bis zum Schlu kaum durchgehalten und sind sehr klein geworden. Pro Schleifegrad wrde ich ggf. mit weniger Trommeltagen anfangen und zwischendrin checken, aber genau das ist ja auch der Spa daran herauszufinden wie man die besten Ergebnisse erzielt. Nach den Durchlufen mit dem Gem-Foam haben die Steine dann auch richtig geglnzt. Fazit: Macht Spa aber etwas Geduld muss man auch mitbringen.

I purchased 3 of these nat’l geographic rock tumblers 3lbs in May 2021. Used them a lot thru the summer as it takes about a month to get one load of rocks to polished stones. I kept them in the shop so any noise didn’t bother me, but they really weren’t too noisy compared to some I have heard. I wouldn’t keep them in the house however.
One was a gift for someone else, but the 2 that I kept both lost power to tumble the canister by August & Sept 2021. So for about $100 a tumbler, I got about 4 months use out of each before they ceased to work. They are quiet and easy to use, but would have liked them to last at least a year or more for the price. Also, after a while the cannister will turn your hands black when you handle it. It is easy to wash off but a little annoying. I left a message with customer service this morning hoping to hear back soon.
I will update if I can after I hear back from them.
Update: – Got a call from customer service same day – they offered to replace the whole units or just the motor if I wanted to replace it. I opted to replace the whole unit as I am not sure of the skill level involved. She said they would ship it right away and it should arrive in 2-3 days. She also said these units usually last for years. Very friendly and with this level of customer service I would not hesitate to purchase these units.

This is my first rock tumbler, but I’m already hooked on the hobby because of how well it works. The stones that came with the tumbler are polishing beautifully. Can’t wait to try some agates and quartz from a recent vacation.

Two downers to note – 1) This thing is loud! It’s in my attached garage, but I could hear it inside the house. I set it on a scrap of carpet pad, and that helped a lot. 2) The belt came off the machine during the second round of tumbling. It didn’t break but did have several small cuts, so it was only a matter of time. Good thing there’s a replacement belt included. So far, so good with that one. I ordered a package of five replacement belts to be on the safe side.

All in all, whether you’re a kid or a practically retirement-age adult like me, I think you’ll enjoy this machine. It’s fun!

I started using the National Geographic 3 lb. tumbler in March of 2021. I’m new to rock tumbling, so as I’ve been getting started, I’ve been studying best practices in hopes of maximizing my results.

*** Edit *** I like this tumbler so much, I bought a second one. ***/Edit ***

This tumbler is extremely well-made. The base, which includes the motor & control panel, is very sturdy. The barrel is exceptional, in that it is larger than other 3 lb. capacity tumbler barrels, and has a very effective sealing mechanism to prevent leaks. There is an extra drive belt included, for when the original belt wears out, or breaks. The overall operation of this unit is smooth, with minimal vibrations. Most of the sound comes from the motor, as the material of the barrel tends to absorb the sound of the rocks tumbling around inside. On speed 3 (the fastest speed), I measured 65 dB right next to the tumbler. Since a rock tumbler has to run 24 hrs. a day, seven days a week, it’s advisable to have it in a garage or basement, so you don’t have to hear it running. While it doesn’t vibrate excessively during use, there is enough vibration to cause it to creep around on a smooth surface. Best to set it on a rubber pad, or otherwise block the base, so it doesn’t creep right over the edge of your work bench.

There are two features to this tumbler that make it unique. First, it has 3 speeds, and even the slowest speed is faster than most other tumblers. This must be taken into account when you are determining how best to fill the barrel & how long to run each tumbling cycle. The second unique feature is the shape of the barrel, which is less deep, but larger diameter than other tumbler barrels. The internal volume is actually larger than that of other 3 lb. tumblers. This allows you to put more rocks in each cycle, with more of the weight of the rocks concentrated in a smaller area & tends to increase the efficiency of the grinding action.

Faster speeds & more efficient grinding cause the rocks to hit each other more often, which will shape and smooth them in a shorter period of time than with other tumblers. But it also may require you to cushion more fragile rocks (such as feldspar) with tumbling media (such as ceramic pellets) to prevent bruising.

Consider the price of this item to be for just the tumbler, with the rocks & grit included for free. The rocks you get are literally a “mixed bag” of all different types & hardnesses. One of the cardinal rules of rock tumbling is to only tumble rocks of the same hardness & durability together in the same barrel. So you don’t want to mix agates with feldspar, for example. Once you separate the included rocks by type, you will find that there aren’t nearly enough rocks to fill the barrel with similar rocks. Best to order 3-5 lbs. of a single type of rocks (search for “tumbling rough” online) so you can fill the barrel correctly for the best results.

After a bit of experimentation, I have found that this tumbler produces the best results when the barrel is 3/4 full. This is about 3 lbs., although the weight will depend on the density of the rocks in your barrel. The main consideration should be where the top of the rocks are, compared to the bottom of the lid. By measuring the depth of the barrel, you can easily make a gauge that will represent the correct amount of space to leave at the top. Too many rocks in the barrel will prevent them from tumbling freely, but too few will just bounce around in the barrel, instead of sliding & grinding against each other. If your barrel is too heavy, it will cause the motor to shut down & you will have to follow the steps in the instruction manual to get it working again. I have routinely filled the barrel with 3 lbs. of dry rocks (plus water & grit) without having it shut down. I have also found that I get the best results when I include some ceramic tumbling media to fill the gaps between the rocks (this helps to carry the grit for more efficient grinding & also to cushion the rocks.)

The included grit & polish packets are insufficient to produce good results. Buy some bulk grit & polish from a rock shop (there are several online.) You will want 60/90 Silicon Carbide for stage 1 (about 4 tablespoons per load.) You will use much more of this than any other grit, as stage 1 can take several cycles to shape hard rocks, such as agate & jasper. Stage 2 requires 120/220 Silicon Carbide (about 4 tablespoons per load.) You will probably need to run one or two cycles in stage 2, until the rocks are smooth. Stage 3 requires 500 grit (either Silicon Carbide, or Aluminum Oxide) – about 4 tablespoons per load. This stage will probably only take 1 cycle & the rocks will start to show a slight gloss & feel really smooth. Stage 4 requires Aluminum Oxide polish (about 3 tablespoons.) This will generally be a single cycle (until the rocks are shiny when dry.) I have never used the included foam cubes. Instead, I run a burnishing cycle using 4 tablespoons of borax powder & a squirt of Dawn dish soap. (All stages require just enough water to almost cover the rocks.)

I run stage 1 on speed 3 (fastest) in 4-day cycles. Empty the barrel, rinse the rocks into a bucket, & examine them. If all of the edges are rounded, set the rock aside for stage 2. If there are still rough edges or large pits, you will need to put the rock back into stage 1. Because most of the grinding happens in stage 1, you will have to add more rocks in each cycle to keep the barrel at 3/4 full. This requires a large enough supply of rocks to keep feeding the barrel. Six pounds of rough might yield three pounds of polished stones. When your pile for stage 2 is large enough, you can proceed. This may take a month or more.

Once you move on to stage 2, things move faster. I run stages 2-4 at speed 1 (slowest) in 7 day cycles. Use the same process as described above to sort your rocks. When you finish stage 2, there should be no rough spots (usually 7-14 days.) When you finish stage 3, the rocks should feel very smooth & maybe slightly glossy (about 7 days.) If your rocks still aren’t shiny after 10 days in stage 4 (polish), you might consider trying another type of polish (such as Cerium Oxide, or Tin Oxide) for an additional 4 days.

This is an excellent rock tumbler that comes with insufficient supplies. My advice is to buy the tumbler, throw out the grit & polish, order your rough rocks and grit/polish from a rock shop, and consider the included rocks as a bonus.

There are many excellent resources available online, including YouTube videos & a forum called “Rock Tumbling Hobby.” If you are considering buying a rock tumbler, you should check these out. My most valuable resource has been a book called “Modern Rock Tumbling”, by Steve Hart. It covers everything involved in the tumbling process, with excellent advice for how to get good results.

*** Edit ***
The motor went out on my tumbler, but I e-mailed [email protected] with a copy of my receipt, and explained the problem. They replied within the hour to tell me that they were sending me a new tumbler as a replacement (no charge.) The new tumbler arrived in two days. Superior customer service!

The noise level was waaay better than I thought it would be. I still run it full time on our screen in porch. In the winter I’ll probably run it in the basement. It’s not a big deal at all honestly. This rock tumbler is AWESOME. It comes with instructions too that are easy to understand and I’ve already run it through the first cycle. The results from the first tumble stage were amazing and I’m even more eager to see the results from the second stage. This isn’t a product to have in your living space, but if you have a basement, a porch, an unused room, or a garage to use it in it’s an incredible product. I’m also glad that I went with the bigger version of the two rock tumblers made by National Geographic. I almost bought the smaller one, but I honestly advise just spending the bit more to get the big one. Five S T A R S