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Rock Tumbler Grit


Rock tumbling grit
"Rock Tumbler Grit" is a silicon carbide powder that is much harder than the types of rocks that are commonly tumbled. If it is tumbled in a barrel with rock and water the abrasion caused by the grit particles rounds the sharp edges off of the rocks. We use about two level tablespoons of grit per pound of rock in a rotary tumbler and 1/2 tablespoon of grit per pound of rock in a vibratory tumbler.
Individual Grits

Coarse Rock Tumbler Grit (60/90 Mesh Silicon Carbide)



Coarse grit for rock tumblers

60/90 Grit
Step 1 (Rotary)



$5.99 Per Pound

$19.99 for 5 Pounds
This is the grit that most people use in STEP 1 of the rock tumbling process in a rotary tumbler. It is an ungraded 60/90 mesh silicion carbide granule. In a rotary tumbler we use about two level tablespoons of grit per pound of rock.

Caution: Do not dispose of used grit, polish or rock slurry down a drain.



Medium Rock Tumbler Grit (150/220 Silicon Carbide)



medium grit for rock tumblers

150/220 Grit
Step 2 (Rotary)
Step 1 (Vibratory)





$5.99 Per Pound

$19.99 for 5 Pounds
This is the grit used for STEP 2 of the rock tumbling process in a rotary tumbler. It is also used for STEP 1 in a vibratory tumbler. It is an ungraded 150/220 mesh silicon carbide powder. We use about two level tablespoons per pound of rock in a rotary tumbler and about 1/2 level tablespoon per pound of rock in a vibratory tumbler.

Caution: Do not dispose of used grit, polish or rock slurry down a drain.


Fine Rock Tumbler Grit (500F Mesh Silicon Carbide)
Also known as "pre-polish"



fine grit for rock tumblers

500F Grit
Step 3 (rotary)
Step 3 (vibratory)



$9.99 Per Pound

$24.99 for 5 Pounds
This is the grit used for STEP 3 of the rotary rock tumbling process and STEP 2 of the vibratory tumbling process. It is a 500F silicon carbide powder. In a rotary tumbler we use about two tablespoons per pound of rock. In vibratory we use about 1/2 tablespoon per pound of rock. .

Caution: Do not dispose of used grit, polish or rock slurry down a drain.




Measuring Spoon - One Tablespoon

grit measuring spoon
$0.49 Each
Stop using the measuring spoon from the kitchen to measure your grit and polish. We use a separate measuring spoon for each grit size to avoid cross-contamination of grit sizes. We keep these spoons in the container with their respective grit size. It's really convenient to have a spoon in the grit container. No more hunting and washing measuring spoons!


Rotary Grit Kits

Four-Step Rock Tumbler Grit Kits for Rotary Tumblers



Rock tumbler grit kit

Four Step Grit Kit



Save $44.96!

Buying a large grit kit will save you $44.96 over the cost of buying five standard grit kits. Your shipping costs will also be lower. In our opinion, this is the best deal on our website!


Large Grit Kit
Only $79.99 Each

Five pounds each of coarse,
medium and fine grit plus 2.5
pounds of TXP polish.

Standard Grit Kit
Only $24.99 Each

One pound each of coarse,
medium and fine grit plus
1/2 pound of TXP polish.
Here are all of the grits and polish that you need to process rocks in a rotary tumbler. Includes coarse (60/90), medium (150/220) and fine (500F) silicon carbide grit and TXP aluminum oxide rock polish.

Large Grit Kits
contain 5 pounds of coarse, medium and fine grit plus 2.5 pounds of TXP polish. Packaged in ziplock bags within corrugated boxes.

Standard Grit Kits
have 1 pound of coarse, medium and fine grit plus 8 ounces of TXP polish. This is enough supplies to tumble up to four three-pound barrels of rocks.

Caution: Do not dispose of used grit, polish or rock slurry down a drain.



Single Use Rock Tumbler Grit Kits for 3-Pound Tumbler Barrels



Rock tumbler single use grit kit
$9.99 Per kit

Here are all of the grits and polish that you need to process ONE barrel of rocks in a small rotary tumbler. Just cut the bag open and dump it in the barrel. The perfect amount of grit for barrels of the Lortone 3A and 33B tumblers and the Thumler's A-R1 and A-R2 tumblers.

Note: We include a second packet of coarse grit because running the rocks for a second week in coarse usually produces much nicer tumbled stones!

Caution: Do not dispose of used grit, polish or rock slurry down a drain.


Vibratory Grit Kit

THREE-Step Rock Tumbler Grit Kit for Vibratory Tumblers



Vibratory tumbler grit kit

Save $34.96!

Buying the large vibratory grit bundle will save you $34.96 over the cost of buying five standard vibratory kits. Your shipping costs will also be lower.

Standard Kit
Only $24.99


Large Bundle
Only $89.99

This three-step grit kit is designed for use in the Lot-o-Tumbler and in the Thumler's Ultra Vibe vibratory rock tumblers.

Standard Vibratory Kit
-- This kit contains two pounds of medium grit (150/220), one pound of fine grit (500F), and one-half pound of #61 Rapid Polish (a sub micron aluminum oxide polish). This is enough grit and polish to process many pounds of rocks. More Information.

Large Vibratory Grit Bundle
-- If you do a lot of vibtatory tumbling, here's your opportunity to save money with our Large Vibratory Grit Bundle. It contains ten pounds of medium grit (150/220), five pounds of fine grit (500F) and two pounds of #61 Rapid Polish (a sub micron aluminum oxide polish). This kit contains 5x as much grit and 4x as much polish as the standard kit for about 3.6x the cost. More Information.

Caution: Do not dispose of used grit, polish or rock slurry down a drain.

Common Questions About Rock Tumbler Grit

Sand vs Grit

Q: Can I Use Sand Instead of Rock Tumbler Grit?



Yes, you can if you want, but we bet that you will change your mind after the first batch of rocks. Here are the advantages of using rock tumbler grit (more formally known as "silicon carbide grit"...

1) Silicon carbide grit is very hard. It is much harder than the rocks that most people tumble. On the Mohs Hardness scale silicon carbide has a hardness of 9 to 9.5 while commonly-tumbled rocks such as jasper, agate, quartz and petrified wood have a Mohs Hardness of about 7. This means that silicon carbide grit can easily abrade the rocks that most people tumble. However, most beach, river, and wind-blown sands are composed of quartz, which has the same hardness as the rocks that most people tumble. Since it has an equal hardness it will be ineffective at abrading them in the tumbler barrel.

2) Quality silicon carbide grit usually occurs in angular particles. That means they have sharp points and edges that facilitate abrasion on the rocks while tumbling occurs. However, most beach, river, and wind-blown sands have rounded particles, which makes them ineffective at abrading the rocks that you are hoping that they will grind.

3) Rock tumbler grit can easily be purchased in sizes that are perfect for rock tumbling. To duplicate the coarse, medium and fine grits used in rock tumbling you would have to purchase a set of sieves, find sand of various particle sizes and separate it into the grit sizes needed for rock tumbling. We are willing to bet that you will burn more gasoline and time chasing these special particle sizes of sand than you would spend buying some good grit. It isn't that expensive.

In summary, you can use sand instead of rock tumbler grit. But, if you do that, the sand may not be effective at cutting the rocks because it has the same hardness as the rocks and it usually occurs in rounded grains. You will probably waste a lot of time and electricity trying to save money using sand instead of rock tumbler grit. We have an article titled "Can I Use Sand Instead of Grit?" that explains this in much more detail.


Grit sizes

recycling grit

Q: Would You Explain the Grit Sizes Used for Rock Tumbler Grit?



Lots of people ask about that. We have an article that describes the man-made material known as "rock tumbler grit" and a chart that explains the various grit sizes. The title of the article is "What is Silicon Carbide Grit?". The Wikipedia article for "silicon carbide" also has a lot of good information.


Q: Can I Recycle Rock Tumbler Grit?



The practical answer to this question is "no," but we will explain the "yes" part in a few sentences. When you place your loaded barrel on your rock tumbler and turn it on, the particles of grit will become caught between the tumbling rocks in the barrel and each time that occurs the grit places a small scratch in the surface of the rock. Over the hours and days of continuous tumbling this happens millions or billions of times. All of this abrasion wears the sharp edges off of the rocks and smooths their surface. It also does some damage to the grit. The grit particles also break and wear down during the tumbling process. So at the end of a week of tumbling your coarse grit will be in a much larger number of particles and each of those particles will be smaller than what you started with.

If you had a screen with a very fine mesh, you could pour the muddy liquid in your tumbler barrel through it and wash all of the mud through. A lot of the granules that remain on that screen would probably be small particles of silicon carbide grit. However, it would be "spent" silicon carbide grit and the value of that grit is probably less than the value of the time that you will spend and the soap and water you will spend cleaning-up after your recycling work.

So, even though you "can" recycle a little bit of grit, we don't know anyone who has tried to do it more than once. :-)

If you see grains of grit in the barrel after tumbling instead of trying to recycle it, consider one of these two actions. A) Run the tumbler a few more days to wear out that grit. It will probably improve the roundness and smoothness of your stones. (You might also try using a little less grit if the rocks that you are tumbling have a Mohs Hardness of less than about 6 or 7. These rocks don't wear out the grit as rapidly.) B) Consider that your barrel might have been too full. If you are filling your barrel more than about 2/3 full, your rocks might not have enough room in the barrel to tumble properly. So, the barrel is going round and round and the rocks are in that barrel locked in a big mass. Reducing the amount of rocks by just a little will give them more space to tumble and give your grit a chance to do its job.


Extra coarse grit

Q: Can I Use Extra Coarse Rock Tumbler Grit?



Here is what we can say about rock tumbler grits coarser than the standard 60/90 used in rock tumbling....

We have used 20 mesh grit a few times but were disappointed with the results. We had some Ohio Flint that was REALLY REALLY hard. We tumbled it for a full month in 60/90 grit silicon carbide and added 50% extra grit to sustain grinding the entire month. (We also added extra water to dilute a month's worth of mud!) At the end of the month it had worn down but still needed a lot more tumbling to get the shape that we wanted.

So we decided to use 20 grit and thought that it would tear up the flint quickly. We added the normal amount of 20 grit and tumbled it for one month. At the end of the month we opened the barrel. Lots of that 20 grit had survived! It seemed that almost all of it had survived. It was almost the same particle size as when we started - it was only slightly smaller. The flint had not budged very much.

We have used 20 grit for several other materials with the same results. Why? When you use 20 grit the particles are really big but there are very few of them to do the grinding. However, when you use 60/90 grit there are a LOT more abrasive granules in the barrel and they grind away everywhere.

We have also experimented with 54 mesh grit. The particles of 54 grit are much larger than the blend between 60/90 and it is large enough to do more aggressive cutting. However, there are still not nearly as many granules in the barrel to do the work of cutting.

In summary, whoever first decided to use 60/90 grit in a rock tumbler knew what they were doing.


1000 grit

Q: Would I Get a Better Polish With a 1000 Grit Step?



We use 500 or 600 grit as the final grinding step before polishing 99% of the time. We get great results and do not think that the extra time and expense of a 1000 grit step is needed. We might use a 1000 grit step if we were competing in the Worldwide Rock Tumbling Contest. Otherwise, the only time we use 1000 grit is when we tumble a very soft material such as fluorite or calcite. We use 1000 grit as the last grinding step in a vibratory tumbler. We then do the polishing step dry, in a vibratory tumbler, filled with crushed corn cob that has been treated with Rapid Polish. The entire bowl is filled with corn cob and we only add a few pieces of the rock we are trying to polish. One-thousand grit is really expensive. Save your money.


Happy Tumbling