There are many options if you are looking for rock tumbler grit, and they are compatible with all models of rock tumblers on the market. Therefore, what are the important factors to consider when buying these refill kits for rock tumbling? Read this to find out the best rock tumbling grit, refill media kits, and rock tumbling supplies available!
Table of Contents
How to choose the best rock tumbler grit and refill kits?
Various sizes and prices of rock tumbler grit are available
First of all, you can find several sizes of rock tumbling grit. Depending on your needs, you may prefer to buy a smaller and less expansive package that will be sufficient for a small batch of rocks. On the other hand, if you were lucky enough to find large amounts of rocks to polish while rock hounding, you may prefer a bigger size that also provides better value.
Overall quality of the rock tumbling grit and grit size
The overall quality of the rock tumbler’s grit is also critical to achieving professional results and getting perfectly polished rocks with a shiny gloss. Generally, rock tumbling is composed of several steps using different types of grit. For each of these steps, a specific size of grit is required. The general principle of rock tumbling is simple. Coarse grit is used for the first polishing step to soften the most prominent edges of the rocks. Then, smaller sizes of grit are used sequentially to complete the rock polishing process. Furthermore, the grade of the grit reflects the size of its grains. As a rule of thumb, higher grades of rock tumbler grit refer to grit containing smaller grains.
The final polishing step is the most critical to obtaining perfectly shiny polished rocks
The final polishing step is the most critical of all. The size of the grit used at this stage can make a huge difference in the overall look of your polished rocks. Therefore, high-quality rock tumbling grit will contain ultra-fine grit composed of aluminum oxide. In addition, there are other options such as the GemFoam technology from National Geographic, and we will review and compare all of these below.
Please also check my previous posts to find the best models of rock tumblers.
Let’s now have a look at the best rock tumbler grit and refill kits!
Best rock tumbling grit: complete refill media kits
4-Steps rock tumbler grit from National Geographic
This rock tumbler grit from National Geographic is one of the most popular options. This product is rated 4.7 out of 5 with over 8,000 reviews on Amazon.
Check this 4-Steps rock tumbler grit refill pack from National Geographic on Amazon
This 4-steps rock polishing kit is enough to tumble 8 to 10 pounds of rock and full instructions. Here is an overview of the rock tumbling process and what this kit contains:
Step 1 – Coarse rock tumbling grit (silicon carbide grit size 60)
This kit contains 16 oz. (1 pound) of coarse rock tumbling grit size 60. This coarse rock tumbling grit is used for the initial tumbling and shaping of rough rocks.
Step 2 – Medium rock tumbler grit (silicon carbide size 150)
The National Geographic rock tumbler grit package contains 13 oz. of rock tumbling grit size 150. This medium size rock tumbling grit is used for smoothing rock surfaces after initial shaping.
Step 3 – Pre-polish rock tumbler grit (silicon carbide size 600)
The kit contains 12 oz. of pre-polish rock tumbling grit size 600. This pre-polishing step will develop rocks for the final polishing step.
Step 4 – Polishing rock tumbler grit (silicon carbide size 1000)
The National Geographic rock tumbler grit package contains 11.5 oz. of rock tumbling grit size 1000. This fine rock tumbling grit is used for the final polishing step of the rock tumbling process
This is a great product from National Geographic, a non-profit organization promoting science for kids. It is a also great option if you want an easy and accessible introduction to rock tumbling. In addition, this is a great option for hobbyists or craftsmen looking to tumble faux glass. However, the final polishing step of this kit rock tumbler grit may not be sufficient to obtain perfectly shiny-looking stones and more professional results. For better results, this kit can be upgraded by adding an extra polishing step using the GemFoam technology.
Final polishing step: should you use GemFoam or aluminum oxide for better rock tumbling results?
Final rock polishing step using GemFoam
GemFoam is a patent-pending technology used to give the final touch to the rock polishing process. A package contains 30 g of these foam blocks. They are combined with the rocks and water for a few more days of tumbling. This extra step ensures smoother stones and better tumbling results. These GemFoam can also be reused up to 6 times, reducing the amount of media used for the final rock polishing step. As appealing as it seems, however, you may find that the polished rocks don’t have a perfectly shiny finish.
Check the GemFoam, a reusable rock polisher foam used for the final polishing step on Amazon
Final rock polishing step using aluminum oxide
This is by far the best option to obtain the shiniest-looking stones. Aluminum oxide is an ultra-fine powder with a grade of 1200. The aluminum oxide, therefore, has smaller grains compared to the classical silicon carbide generally used for pre-polishing steps. For the most professional results, I strongly recommend using aluminum oxide for the final step of rock polishing. For more flexibility, you can buy it either separately or as part of a complete kit of rock tumbler grit.
Check this Grade 1200 Fine Aluminum Oxide for Final Polish Step Rock Tumbling
Rock tumbling using filler media: when and how to use ceramic media or plastic pellets?
Some of the refill kits for rock tumbler grit also include filler media such as ceramic or plastic pellets. While using filler media for rock tumbling is not mandatory, it still offers many advantages and generally improves the rock tumbling process.
First of all, as the name says, filler media is often used when tumbling smaller batches of rocks or if you want to polish larger stones. In addition, filler media can reduce clogging and improve the movement of the stones and the grit as the barrel of the rock tumbler is rotating. As a result, filler media can improve the shiny aspect of the rocks, as well as reduce the time required for each of the tumbling steps. Furthermore, filler media can act as a cushion during the tumbling process and it is specifically useful when tumbling softer rocks to reduce rock breakage or cracking. Finally, they help to reduce the noise produced during the tumbling process.
Check these large ceramic pellets and filler media for rock tumbling from National Geographic
All of the filler media available are reusable and can be used several times. They can be washed and dried to be able to use with your next batch of rock tumbling. Although some people recommend reusing the filler media with the same type of grit it was originally used with, it is not required to do this and the same media can generally be used throughout the entire process if they are washed properly.
There are 2 different sizes of ceramic filler media that can be used for rock tumbling. The smallest size available is good to use for smaller rocks, but keep in mind that their size will decrease over time. Therefore, by buying the biggest size, you will eventually end up with small-sized pellets that you could use on their own, or mix with a new batch of larger pellets.
Nowadays, you can also find small plastic pellets that could also be used as a filler media for rock tumbling. These beads are made from high-quality and durable American polypropylene plastic. The main advantage of this filler media compared to the classical ceramic pellets is that they are floating in the water. As a result, it is very easy to clean them! Afterward, all you need to do is dry and save them for your next batch of rock tumbling.
Check these plastic pellets rock tumbling filler media on Amazon
Complete refill kits of rock tumbler grit
Although there are several kits of rock tumbling grit available online and in-store, in my opinion, there are 2 main products that stand out from their competitors. I would easily recommend any of them and your final choice should be more guided by your needs.
Best complete kits of rock tumbling grit for kids and beginners
As you may have noticed already, I am sold to National Geographic not only because it is a trusted brand, but also because these are great products to get children interested in science. These kits are appealing and provided clear and illustrated instructions.
Moreover, the kit of rock tumbler grit from National Geographic is complete and contains everything you need to tumble your first batch of rocks. This is great for amateurs and beginners who want to have a great first rock tumbling experience. This is also why it makes it the perfect gift for any geology enthusiast!
This kit includes 3 pounds of rough rocks from Madagascar and enough grit to tumble them and get fully polished stones. In addition, it contains ceramic filler media and jewelry fastenings. Definitely a good value and a great buy!
Best complete kits of rock tumbling grit for advanced or professional geologists
If your main goal is to obtain perfectly polished stones, I would strongly recommend this complete kit of rock tumbler grits from Polly Plastics. This product is rated 4.7 out of 5 on Amazon with over 700 ratings. I also personally like this family-owned company from Michigan because they sell high-quality products made in the USA.
This complete kit contains the perfect rock tumbling grit selection, including aluminum oxide grade 1200 for a perfect shiny touch. It also comes with plastic pellets that can be included in your tumbling batch as a filler media. Nevertheless, beginners should not be afraid to use this high-quality kit since it comes with clear tumbling instructions that are easy to follow.
This kit contains enough grit to tumble 15 pounds of rocks! It contains 1 lb of 60/90 Coarse Silicon Carbide Grit, 1 lb of 180/220 Medium Silicon Carbide, Grit, ½ lb of 500 Fine Silicon Carbide, ½ lb of 1200 Aluminum Oxide Polish, and 1 lb of premium highly-resistant polypropylene plastic filler pellets.
Personally, this refill kit of rock tumbling grit is my favorite! This is a great value providing optimal results and perfectly polished rocks.
Buying rock tumbling grit refill in bulk
If you are planning to run multiple batches of rock tumbling or if you own a rock tumbler with a high-capacity barrel, then buying tumbling grit in bulk is the best option. You will get more grit from this kit. However, the filler media is not included.
Here is the amount of grit provided in this kit:
2 lbs. 60 Coarse Silicon Carbide Grit
2 lbs. 220 Medium Silicon Carbide Grit
1 lb. 500 Fine Silicon Carbide Grit
1 lb. 1200 Aluminum Oxide Final Polish Grit
Check this 6 lbs bulk refill of rock tumbler grit available on Amazon
Best rock tumbling grit: the final verdict!
In summary, the best refill-kit for rock rumbling is the one that fits your needs. There are several options listed above and it should be easy to find one that you like. I hope that you enjoyed reading this review. Please don’t forget to share your rock tumbling experience with us in the comment section below.
You can also have a look at my other related to geology including a review of the best rock hammers and rockhounding tools or if you want to find good sluice boxes for gold mining.
