Polishing Your Jewelry In a Tumbler
Tumblers are often used as one of the final steps in creating jewelry, especially for those doing production runs. They can take out some of the effort required in each individual piece of jewelry by tumbling with the right shot for your purpose.
So, let’s dive in and talk about polishing jewelry in a tumbler, why you should do it, and what it actually does to the jewelry you’re working with.
What Tumbling Does
We do need to be specific when we discuss tumbling because many people have a weird interpretation of what it does.
Tumbling with stainless steel shot essentially burnishes the surface of the jewelry in the tumbler. Burnishing will smooth out very small scratches, shine the surface, and create a layer of work-hardened metal on top of the piece.
Tumbling does not fully work harden your material. The thin layer is resistant to scratching and will resist bending a little bit but the interior of the metal isn’t affected. The hardening effect can “work” with very thin pieces of metal (ear hooks are a good example) but even there the material is only resistant to the initial bend.
The thing is… stuff like ear wires can be hardened quickly and efficiently on a stamping block with a mallet. Proper work hardening will make the wire resistant to moving throughout the range of motion, rather than being hard to bend initially before you have no resistance.
What you can do is attain a great finish in 30 minutes to a couple of hours without having to sit there and polish each piece individually.
Tumblers should primarily be thought of as a finishing tool for metallic surfaces, the mechanical benefits granted are a bonus and only a few molecules deep.
What You Need
Tumbling jewelry is a pretty simple process overall, just requiring a few items.
- Tumbler- Barrel tumblers are the most common, but vibratory tumblers also work well for tumbling jewelry. These don’t have to be super high-quality but they should be a bit further up the food chain than the National Geographic plastic tumblers.
- Tumbling Shot or Media- We’ll discuss shot selection in a moment, but you’ll need some sort. Mixed stainless steel is the way to go if you don’t have a specific use in mind, but there are quite a few options.
- Burnishing Compound or Soap- I use a few drops of Dawn dish soap in my tumbler, you can use whichever liquid soap or burnishing compound you feel will work best. Burnishing compounds are desirable if fire scale needs serious removal.
- Distilled Water- Try to always use distilled water when working with jewelry, it prevents calcium stains that show up when the water dries.
- Your Jewelry- Ideally your pieces of jewelry will be cleaned up before going in the tumbler, but steel shot will clean off fire scale (not fire stain) most of the time. You have to tumble pieces of jewelry before you set the stones or you risk damaging the stones.
It doesn’t take a lot to get your jewelry polished in a tumbler, but you also need to time it correctly. Tumbling should take place right before setting the stones in the piece, too much earlier and you’ll lose the finish. After the setting, you can break the stones.
How to Pick Tumbling Media
If you’re not sure what to go with, you can simply use a “jeweler’s mix” of stainless steel shot. This includes a whole bunch of different shapes made of stainless steel and is good for receiving a great, burnished finish for the majority of pieces.
The following types of tumbling media are all readily available:
- Stainless Steel Pins- Quick and easy, these pins will quickly burnish the surface of most nonferrous metals. The pin shape tends to leave a half-bright finish and the media works quickly due to the weight of the stainless steel alloy.
- Mixed Stainless Steel- Comprised of pins, balls, and different polyhedrons, this is sometimes called a “jeweler’s mix” and produces a bright finish in a small amount of time.
- Walnut Shell- Ground walnut shells with a special treatment create a media that leaves an incredible, mirrored finish on jewelry. It’s quite slow compared to many other types of tumbling media.
- Ceramic Polyhedrons- Heavy, dense ceramic media can quickly grind down the exterior of metal. Too aggressive for polishing use, but they can come in handy for those who are casting parts.
- Ceramic Pyramids- Abrasive pyramids that are available in different grits. They’re useful in some cases, but it’s situational and they’re usually too aggressive for home jeweler use.
- Porcelain Balls- These tiny (~2mm) balls produce a finish even in tight areas due to their small point of contact and light impact. Great for delicate work like filigree, but not the best choice for many applications.
There’s also a variety of ceramic media in different grits available for specialized uses, but these tend to vary a lot from brand to brand. For the vast majority of polishing, one of the above types of media will do the trick.
As a general rule, stainless steel shot mixes are the way to go. They’re usually what’s referred to when people talk about tumbling jewelry.
For cast pieces and others that may need a bit more surface removal, the ceramic pyramid-style media is the best place to start. Despite the simplicity of this operation, people tend to develop their own specific systems.
Following instructions comes second to getting a great finish, so don’t be afraid to experiment.
How To Polish Jewelry In a Tumbler
Step 1: Prepare Your Pieces
Knowing which pieces to tumble can be half the battle, especially when you’re not familiar with using the tool. Tumbling is really only done directly before stone setting, at least if you want to get the best results.
Any piece going into the tumbler should be near the final polishing stage, cleared of excess solder, and with a uniform sanded finish. The last bit is important to make sure you have the same finish on all of your pieces. I prefer using a 1000-grit radial silicone disc as final preparations, but everyone finds their own way.
While tumbling will clear up minor amounts of fire scale, it doesn’t touch excess solder or most scratches. If you’re not quite sure if you’ll be able to close up a scratch it can be helpful to see what happens if you burnish a small portion with an agate burnisher.
Knowing what will and won’t be sorted out in the tumbler takes time, but with the above guidelines, you should get a great finish.
Tumblers also work well for deburring small pieces such as jump rings, but for most applications, you’ll be better served just filing off any burrs and continuing the creative process instead of waiting for the tumbler to run.
Step 2: Set Up the Tumbler
Artists use both rotary and vibratory tumblers. I recommend a cheap rotary for the beginning artist, they’re a lot cheaper despite taking a bit longer to use.
You’ll first want to load the shot into the drum, followed by water and soap or burnishing compound. You really only need burnishing compounds if you’ve got quite a bit of fire scale. Flaked Ivory soap or a bit of dish soap works fine in the majority of cases.
The procedure is simple:
- Add tumbling media equal to about half the container’s volume.
- Add water to ½” to ¾” over the top of the media
- Add soap or burnishing compound and gently swirl the bowl (vibratory) or barrel(rotary) to mix it in.
- Add in your jewelry, ideally enough to loosely fill the second half of the tumbler
You may also want to find a way to dampen the noise if you’re working in an area where you live close to others. Tumblers can get pretty loud. It’s less necessary than when you’re working with stones, however, since the tumbler will be run for a much shorter period of time.
Step 3: Run the Tumbler
Once you have that done, it’s time to turn the tumbler on and let it run.
How long you run it depends on what type of tumbler you have, what metal you’re tumbling, what kind of pieces you’re tumbling, and what media you’re using. For the most part, you’re looking at 6-8 hours with a “standard” rotary tumble and a normal load, but you may not need this much time.
You can check your pieces every 20-30 minutes. With a rotary tumbler and stainless steel shot, the majority of the surface burnishing should be done within an hour depending on the pieces you’ve got. Vibratory tumblers can work more quickly.
I recommend figuring out what works for you. As far as I can tell, the 6-8 hours many people use are just to be 100% sure, and it’s mainly used in shops where it’s a natural part of the production process. It’s also done for components like ear wires in an attempt to harden them. 1 to 2 hours usually does the trick with stainless steel shot in my experience.
If the water starts getting very dirty you can change it out and add more soap or burnishing compound. This normally isn’t a problem, however, provided that you did the prep work on your pieces properly.
Step 4: Inspect Finish
Once you’ve run the tumbler long enough, you can pull out your pieces and take a look. Look over every piece, but you should have a good idea of whether or not to run the tumbler again pretty quickly.
Remember that tumbling will leave behind excess solder and it’s not enough to sort out file marks and scratches on the surface of the metal. Instead, you’ll just end up with shiny excess solder or shiny metal that still has deep scratches.
If satisfied, then you can separate all of the jewelry from the shot. Get your pieces out and set them aside, you still need to rinse and dry the tumbling shot or media unless you’re planning on using the tumbler again within 24 hours.
If you’re running a two-stage tumbling operation (ie: ceramic pyramids and then stainless steel jeweler’s mix) then you’ll want to go back and replace the shot with your next media.
It’s not a bad idea to have multiple barrels to make this process quicker, allowing you to simply switch to the final burnishing mix from an abrasive mixture by pulling your jewelry and putting it in another prepped barrel.
Step 5: Clean and Dry Media
Dirty media can lead to problems over time, often by depositing colors on the surface of the material. I’ve also seen problems with cleaning cycles where the person didn’t neutralize the vinegar after a washing cycle but it’s less common.
Place the media in a jar or bucket and add some dish soap. Get your hands in there and swirl it around, scrubbing the media by hand. Afterward, dump off the soapy water and then refill the barrel with clean water for a rinse.
Drying the media is simple: spread it out on a towel somewhere it won’t be disturbed for a few hours. It’ll dry quickly, allowing you to easily store it.
Try not to let stainless steel sit in the water for too long. While stainless steel usually doesn’t rust… there’s no point in pushing things if you don’t have to. Any rust that manages to form will transfer ugly orange stains to your jewelry on the next cycle, making more work for the artist instead of saving them effort.
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