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Rock Tumbling

My First Tumble: Trials and Triumphs

Hey, you gotta learn somehow right? This is how my very first tumble went. I hope that I can help yours turn out better!

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A striped rock from my first tumble

A Brand New Hobby

Before I got my first tumbler, I just had rocks… a lot of rocks. My wonderful friend noticed how I was bringing rocks home from every hike I went on, and gave me a National Geographic Hobby tumbler for Christmas. The hobby tumbler included enough grit for one full tumble and even came with a barrel full of rocks. I had been gathering rocks for so long that I immediately discarded the rocks that were included with the tumbler in favor of my collection of beautiful smooth stones from the beach. I was so eager to have polished stones, that I purposefully chose the smoothest stones to tumble first because they would take the least amount of time. And since the rocks were already very smooth, I decided it would be efficient to go ahead and skip grit stages one and two, and jump right ahead to the fine grit stages (which I would later regret).

First tumble stage 2 results

I dutifully followed the instruction packet (except for the part where they recommend NOT skipping any stages) and started my rocks on an 8-day tumble. After (barely) waiting those 8 days I eagerly dumped my rocks to find that they were no closer to the smooth, glossy perfection I was hoping to achieve. Eager as I was, I did end up seriously questioning my decision to skip the first two grit stages. I did some research online and found that most experienced tumblers did not recommend completely skipping the course grit stages as I did. These stages are critical for shaping the rock surface and removing the tiny imperfections that inhibit a lustrous shine.

First tumble stage 2 results

In my research, I found that I might have made more than one mistake. I decided to cut my losses and start the same rocks over again at stage 2. I was slightly disheartened to have wasted over a week, but at the same time I was glad to be learning this new trade. I continued my research and discovered the promised wonders of ceramic tumbling media. I bought one pound of the National Geographic brand and decided to give it a try. I let this batch of random sea rocks tumble for just under 6 weeks total, now allowing each stage to tumble for just over a week, and the polish cycle for two weeks. Of course, I had already used up all my stage 3 grit, so I had to buy more tumbling grit. I played it safe and purchased the National Geographic brand grit for consistency.

This is before I discovered wash cycles

Final Results

I was so excited for that final reveal after the polish stage. I had seen so many proud rock tumblers confidently dump the contents of their barrels into a strainer and spray to reveal beautiful, glossy stones. The day finally came, and I emptied my rocks into my metal strainer and washed them thoroughly with the hose. The hodgepodge of various beach rocks shone beautifully while wet, but I was terribly disappointed when I laid the stones out to dry. I noticed that the rocks adopted a matte finish and were scored with small white scratches. It took me longer than I would like to admit to realize that the metal strainer was the culprit. I immediately cursed my foolishness and made a mental note to buy a plastic strainer as soon as possible. In the meantime I used plastic wrap in the bottom of the metal strainer to protect the stones from any further damage. Even though that resolved the issue of the scratches, the dullness of the stones was a slightly more complicated issue to work out.

Final results of first tumble

What Went Wrong

I took to the computer again to try and make sense of my apparent failure. I had followed all of the instructions this time around and even went beyond recommended tumbling times. I wouldn’t realize until much later on that the burnishing step after stage 4 is absolutely critical. After a full month of sulking over my matte rocks, I performed the 24-hour burnish cycle on my next batch of rocks and found that they came out absolutely perfect. I threw my original dull rocks back into the tumbler to see if burnishing was really the magic solution. The stones came out beautiful and shiny, just as I had hoped from the beginning. Even though the trial and error factor of this hobby can sometimes be frustrating, I always appreciate the experience of learning and improving. Watching each batch of rocks turn out better than the last is almost better than having every single batch turn out perfect…. almost.

Tumbling Recipe

I should have just followed the instructions that came with the National Geographic tumbler, but here is what I did instead:

GritTime
#3. Silicon Carbide 500 1 tbs8 days
#2. Silicon Carbide 220 1tbs8 days
#3. Silicon Carbide 500 1tbs10 days
#4. Aluminum Oxide 1200 Polish 1tbs14 days
National Geographic Gem Foam3 days
Tumbling recipe

You might notice that I used grit 3 twice. I mistakenly thought it was OK to skip stages because my rocks were pretty smooth to begin with, but I was wrong. So I went back to stage 2 and followed the instructions from there on out. I didn’t do any wash cycles for this tumble, but I did scrub the rocks with a toothbrush before starting them on the final polish. I now know that doing a wash cycle is much easier and more effective. The National Geographic Gem Foam really improved my results, and before that step my rocks were dull. I was so disappointed at the end of the final polish, and I thought I had messed up the rocks completely. Luckily, rock tumbling is a relatively forgiving hobby, and it is actually really difficult to completely ruin the rocks. You can keep trying to make your rocks shiny after that final cycle is finished, even if it means completely starting over.