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Recovering from tumbler sludge

Hi all. My usual supply store recently sold me a new box of tumbler
soap. I used it once and opened my tumbler to find it filled with
black sludg= e and my sterling looking like dull stainless steel. My
stainless shot was very dull grey as well. It turned out I had been
sold aluminum oxide for rocks rather than my regular soap.

I have been cleaning and running the shot steadily for a day and a
half and still get black residue. I brass brushed the sterling and
have been running them as well, hoping to save them but they are not
coming up bright. The shot looks pretty good at this point.

My question is - will the sterling recover and is my shot ruined and
tumbler permanently damaged?

Stephanie Morton

I run a rotary tumbler with stainless shot with just boraxo hand soap
and after neglecting it for some time I get the smae results you’ve
described, grey work, black sludge and dingy shot. Simply very hot
water from the tap swirling with hand (burning) in a strainer a;ways
clears it up within 5-10min. Then back into tumbler with boraxo. No
otheer media or solution is used in this.



My question is - will the sterling recover and is my shot ruined
and tumbler permanently damaged? 

No, your tumbler and sterling will be fine, they only need cleaned a
bit. Just add a generous amount of baking soda to the shot and
sterling, a small amount of water, and then let it tumble. It can
take a few rounds of rinsing and redoing, but does come clean.

You can also tumble the shot alone w/ a few tablespoons of play
sand, ivory soap chips, and water to clean it out really fast. If you
can heat the sterling enough to burn/smoke off the residue (no heat
sensitive stones), pickle, and then tumble in the clean shot, you
can recover your work even faster.

Good luck!
snowy and magical in Ohio


Run the whole mess for about 45 mins to an hour in flat coca-cola (no
water). Rinse. Repeat if necessary. Should clean it up beautifully.

Karen Goeller

Put your shot in the barrel with your regular soap and tumble for a
couple of hours, wash and repeat. If you can, ultrasonically clean
your silver before trying to polish again. The fine alumina is
obviously cross contaminating and may need several attempts to get
rid of it. Multiple short cleasings will be better than one long


Thanks Karen for the suggestion. I ran the work through for 2 one
hour session with flat coke. The silver still remains noticably
greyer than it should be. It is 150 g of silver so I am keen to get
it up to sparkle.

Stephanie - This can all be fixed. What you have done is add
abrasive grit to your steel and jewelry. It is the rough equivalent
of running an abrasive media in the first step of tumble finishing
your jewelry. The black stuff is the result of the abrasive scouring
the inside of your rotary tumbler as well as smoothing your jewelry.
Because there wasn’t enough liquid, the accumulation of grit and junk
from inside your tumbler created the black mess. Stainless steel is
harder than the abrasive so it is ok. Fixing your tumbler, steel and
jewelry is an iterative process.

First - open a can of regular Coke, and let it lose its fizz.
Heating it works well, or just let it stand. Then add the liquid to
your tumbler, jewelry and shot included. Run for 20 minutes. That
should cause most of the black sludge to go away.

Second - Wash everything very very well. Separate out your stainless
and rinse well. Set aside to dry.

Third - Examine the rubber liner of your tumbler. If the inside of
the tumbler is rough or deteriorating, you need to replace it.
Compare the interior with the edge that didn’t get abraded with the
aluminum oxide and see if there is a difference. If you can’t see or
feel the difference, proceed with caution. The potential problem is
that the liner is embedded with the abrasive and then you no longer
can get a high polish with that barrel. In any case mark it clearly
so that you know it might be a future problem with finishing. If your
lid is also rubber, check it too.

Fourth - If you have an ultrasonic cleaner, use it on your jewelry,
in small batches - so that you don’t further damage your jewelry. If
not, manually clean it as well as possible. If it still has embedded
black stuff, try to pick it out of crevices. If your jewelry is no
longer covered with gunk, you can proceed to polish it. If you still
can’t get it clean, try running it in a vibratory tumbler with
appropriate cleaning liquid. Triangle shaped media will help get the
gunk out of crevices. Then proceed to burnish with your steel and the
correct liquid.

Finally - This isn’t the first time I’ve heard of such a problem. To
avoid it in the future, I strongly recommend using a solution
intended for what you are doing. Several of the jewelry supply houses
sell concentrates for burnishing. If you wish to keep using the
powder, put it in a container on which you tape the label of the
contents. Regular soap is not a good alternative. Steel needs a
different pH than abrasive media. It also requires a surfactant.
Because you run in a closed system, it is important to get all parts
of the process exactly right. The liquid burnishing compound is easy
to measure to get the correct concentration. With all the work you do
to make jewelry, do the last part as well as it can be done too.

Good luck,
Judy Hoch

could it be that you have too much silver in there at once. I’m not
sure how large your tumbler is, but mine wouldn’t be happy with

Amery Carriere Designs
Romantic Jewelry with an Edge

Hi Jeni. Thank you for your suggestions. The baking soda worked
great and Iam much relieved. Orchid is truly wonderful.

thanks again,
Stephanie Morton
(in snowy Toronto - early for us!!!)

Many thanks to those who offered suggestions regarding my tumbler
sludge woes. The baking soda slurry cleaned up the silver nicely
(better than the coke, fyi). Wishing everyone a peaceful Holiday

Stephanie Morton