Behind the Scenes: Wire Brushing & Tumbling Metal Clay

rock tumbler burnishing metal clay charmsTools for Tumbling

After my silver metal clay charms have been fired in the kiln, I like to polish them using a rotary tumbler. This process work hardens my silver, creates a slick shine, and burnishes any rough edges. Below I've provided a short video that demonstrates how I tumble Hint Jewelry's metal clay charms. Here's a list of the tools used:

Brass Wire Brush
Rubber Block
Lortone Single Barrel Rock Tumbler Model 3A
Dish Soap/Burnishing Powder
Stainless Steel Shot Mixed Shapes (2 lbs.)

When silver metal clay comes out of the kiln, it looks pure white like porcelain. So before I start tumbling my charms, I run a brass wire brush over the surface flatten the silver particles so they reflect light. The brass brush allows me to get into all the crevices where the tumbler is unable to reach. I bought the wire brush at my local hardware store and the rubber block can be found at any shop that sells metal clay equipment. The rubber block was definitely an impulse buy, and I wouldn't consider it one of my essential tools. Sometimes it helps to hold your metal clay steady when you are filing, brushing, or hand burnishing.

My handy studio assistant, the Lortone Tumbler, was a Christmas gift from my honey, so I missed out on all the research done at Ed's Gems. He was able to purchase the tumbler, steel shot, and burnishing compound all at the same time. If you have a local lapidary shop featuring gems and minerals, I'd stop in a get a tumbler demo and do some research. If you don't know where to purchase a tumbler locally, Lortone provides a dealer search tool. Of course you might also check on Ebay for an inexpensive Lortone tumbler.

My two pounds of steel shot has three different shapes: ball, pin, and what looks to me like like a spaceship. The first time I used it, I left the wet shot in a metal colander and everything rusted. Oops! No worries, I simply ran the steel shot in the tumbler with some water and burnishing powder and everything cleaned up real nice. Since then I spread my shot out on a towel to dry after tumbling.

I haven't had any major problems with my tumbler and the maintenance has been minor. A simple squirt of oil on the shafts every 30 days of operation keeps it running smooth. After about a year and a half of using my Lortone tumbler, I did have to move the motor over to tighten the drive belt because my barrel stopped rotating in a consistent fashion.

I read somewhere that it is not advisable to use burnishing powder with your metal jewelry, but alas I'm stuck on the magic powder the gem guy sold us, and so far I haven't seen any negative results. Nevertheless, most of the metal clay books I've read recommend a squirt of Dawn dish soap instead of burnishing compound in your tumbler.

I tumble my charms for about 2 hours. Sometimes I've let the tumbler run 3-5 hours, but I've found that some of my smallest charms risk having certain details burnished away, so I try to to keep an eye on the time.

If my Lortone tumbler video has you desiring more information, you may also want to check out this highly detailed Youtube video made by Cool Tools.

For the full scoop on Hint Jewelry's process, be sure to check out my weekly blog series called Behind the Scenes.


  1. Thanks for sharing more of your process. It is fun to learn from people I admire.

  2. How very cool! I was a bit apprehensive about a tumbler. It's not scary at all! Thank you!

  3. It turns a lot slower than I thought it would, interesting..

  4. Gaea, so glad I opened the tumbler door for you!

    Niki, I was surprised by its speed also and its ease of use.

    Stregata, so happy to see you this week and share in the making of things :)

  5. Love these videos!

    The teacher in me needs to say though, that you're *flattening* the silver particles, not raising them. When silver is exposed to heat, the metal crystals raise like a mountain range and only reflect white light. When you use a brash brush, you're flattening them a bit so instead of mountain tops, you have rolling hills. When you burnish them or put them in the tumbler you're creating the ninth tee on the golf course. Flattening them all the way. That's why extremely burnished or polished silver is soooo shiney. There's nothing to interfere with light bouncing off every curve and surface - allowing the silver spectrum to shine bright.

  6. Thanks Lora for clearing up the misinformation on the silver particles and giving me a mental image to hold onto. Love your technical expertise, so I'm grateful for your share :)

  7. This post has all-new meaning to me after my weekend at BeadFest...I took a class with Sherri Haab, and she was telling us about using rock tumblers to help clean up our metal clay after it's come out of the kiln. I am SO in love with metal clay now, and it's nice to see that you showed the one she mentioned...To hear from 2 places that it's a good one makes me feel better about adding it to my wish list :o)


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