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Tumbler turning jewelry black

I am brand new to this so bear with me please! I finally purchased a
rotating tumbler and ss shot to polish my silver etc. I put a drop
of dawn in like everyone has suggested with enough water to
cover,etc. I let it run for 2 hours. When I opened it up, all of my
jewelry was black! Well more like steel gray. What did I do wrong!
Thanks in advance for any help.

Hello Karen,

Most people seem to think that the inside of the barrel is the cause
this black/gray issue on tumbled metal.

I’ve found that if you use distilled water, it will eliminate most
water-chemistry issues right off the bat.

Instead of soap, I use a burnishing compound liquid (sorry, I can’t
remember the name right now). It’s like 2 tablespoons per gallon of

After every other tumbling, I’ll take the rubber barrel and scrub it
gently, but firmly with warm, soapy water. Also clean the shot in
this way as well.

If I’m diligent about this, I found that I don’t have the gray scum
issues that I have in the past.

Be sure to wear gloves when using the burnishing compound/water. It
can irritate your skin.

On a side note, I found that plastic grids for yarn needlepoint make
an excellent strainers. I have a plastic colander in which I use a
round grid that I can use to lift out the jewelry and shot after
draining the liquid.

Good luck,
Tracy Burlison

Try washing out your barrel with baking soda and water, rinse well
and then run another load. That usually clears up the black gunk



Likely, not enough water and too long a run time. For steel shot, I
rarely let it go more than an hour, and I make sure there’s a lot of
water in there… not “just enough to cover.”

Good news - to clear it up quickly and beautifully, pour Coke (flat
or otherwise, both work just fine) over the shot and silver and
tumble the whole thing for about 45 minutes. Rinse and wash in clear
water. It will be like new!

Also, if your new tumbler barrel is black rubber (like a Harbor
Freight tumbler) and “stinky,” you may just want to give it a good
tumble with shot and Coke and let it run for about 2 hours (NO PIECES
IN IT) to get the manufacturing “goo” off the inside of the rubber
barrel. Wash well with soap and water and allow to dry, then use as
normal. I’m really not a fan of the black rubber barrels as they seem
to be reactive with a lot of things and to gunk up more easily than
the hard plastic barrels.

If you have a flat rotary style tumbler and are having problems with
the barrel, the other thing you might want to try is a plastic
mayonnaise or peanut butter jar… roughly the same diameter, but
none of the reactivity. Also much easier to open and cheaper to
replace :-).

Hope this helps!

Karen Goeller
No Limitations Designs
Hand-made, one-of-a-kind jewelry

Despite many testamonials to the contrary detergent of any kind is
going to attack the rubber in your casting drum. This results in the
dissolved rubber being deposited on your work and shot.

When I made this discovery many years ago I found that by putting
about a teaspoon of Bon Ami (a polishing cleanser) in the drum with
your shot and water, letting it go for an hour or two, was all that
was necessary to clean everything up.

Use the Loretone non-detergent tumbling compound. It’s cheap and
won’t kill your drum. Around where I live hobby shops carry it.

Les Brown

L.F.Brown Goldwork

Clean it up with Simple Green. It is a household cleaner you can get
anywhere. Then use it from now on instead of dawn.

Are you using the cheapie Harbor Freight tumbler? I haven’t managed
to get a good result on copper, with mine. The folks on one of the
jewlery making forums, have several suggestions. Try a different
tumbler, the barrel may be the problem. Try a different agent,
someone had good luck shaving a little Ivory soap, someone else found
instructions for lining it, with a yogurt container. There were
several suggestions on running it with some baking soda or other
cleaners, first. I need to try all of these. some folks had good
results with them, some didn’t. Some folks feel that the rubber in
the barrel is the problem. Yet other folks have never had a problem
and they have bought the tumbler, just for the barrel, since it would
fit their namebrand tumbler. Be aware, the belt that comes with this
tumbler has a bad rep, get a replacement, before you depend on it.

Cairenn, the Howling Artist

Hi Gang,

Another thing beside Coke that works very well for cleaning tumbler
shot & barrels is Draino. I’ve been putting tablespoon or 2 of the
granular type in a tumbler with about 5 lb. of shot & 2-3 oz. of
water. Let it run for 1/2 - 1 hour. Rinse the shot & tumbler in warm
water, & you have a tumbler & shot that’s cleaner than it was when
new. If you want you can use sodium hydroxide (lye) in place of the
Draino; that’s what the active ingredient in Draino is. The nice
part of using Draino is it can go down the drain & might even help to
clean it out.


Karen - Like everything else, using a tumbler takes a bit of
education. This article from orchid archives
should help.

My bias is to use products made for the process - a burnishing
liquid would work much better than regular soap. Just steel isn’t
enough to get a decent finish on jewelry. This is a whole process
just like hand finishing. First you have to smooth the jewelry - in a
tumbler, you use a mild abrasive in some kind of media. Then the
steel to burnish. And it can all be further refined in a dry media to
achieve a smooth high polish.

To clean up your mess, drain the dirty water, and run everything
with a can of regular coke that no longer fizzes. Run for 15 to 20
minutes, then wash everything well with warm soapy water, rinse with
clear water.

Also, IMHO, 2 hours is way too long to run work in steel. I usually
run for 30 or 40 minutes. Anything longer starts to degrade the

Judy Hoch

There is a tiny piece of metal that is not silver - probably a
finding or something - in the tumbler when the pieces turn steel
coloured. Take it all out, clean the steel and barrel with
dishwashing soap, and heat the pieces to get rid of the colour.

Tumble again, and be sure that the junk is not there anymore. ONE
spring ring is enough to mess up evrything…


I’ve had this happen whenever I tumble cast pieces where there is
the tinyest but of investment left. It wasn’t just that the tumbler
was black and the jewelry coated, the “liquid” in the tumbler was a
viscous black goo. I got it off the jewelry by heating the pieces
with a torch and pickling them. Then tumbled again after the tumbler
and shot were cleaned.

A warning about using lye (sodium hydroxide) on tumblers with
aluminum parts.

The aluminum will develop lots of pits and holes is the lye is not
completely cleaned off the aluminum. Remove the aluminum plate from
the rubber lid gasket and clean it.

I use Sodium Bicarbonate (baking soda) to clean our tumbler barrels
and stainless steel shot.

If you don’t care for the sugar mess of coke, use Simple Green spray
cleaner found in any grocery store. I found that using burnishing
compound and a squirt of SG keeps any mess from coating the jewelry.

Did you use the buffer before tumbling? When I first bought my
tumbler, I was relatively new to jewelry work, and I had exactly the
same problem. I was sure the black rubber barrel was somehow
involved. After a bit of detective work, I learned that I was not
cleaning my jewelry sufficiently after using the buffer, assuming
that the tumbler would help to clean it. The tumbler was then taking
the small amount of grease left from the buffing compuinds, and
spreading it very efficiently throughout the shot and the inside of
the barrel. Grey goo everywhere. I used Bon Ami, Comet, or fine
jeweler’s pumice to scrub the pieces, and poured some in the tumbler
with the shot, water, and dish soap (no jewelry) as well. I ran it
for 10-15 min and rinsed, then repeated until all was scrubbed
clean. It only took 2-3 runs. Since then, I always wash my buffed
pieces with a soft brush and soapy water with ammonia. I have never
again had the problem.

I would suggest you clean out your barrel and shot well, then run it
again, exactly as before, but without the jewelry. If you get more
black goo, the problem is the barrel or an interaction between it
and something you are using. If you don’t, the problem is something
related to the silver/jewelry pieces, and contaminants left on it
that should not be there.

I have used all of those mild abrasives at one time or another in my
tumbler. They are gentle and effective when shot starts to get a
little dull. Incidentally, as for time, I have often run my tumbler
(an old Loretone, with steel shot) for 10+ hours/overnight, esp. if
I want to harden earwires or other fine wire work. It has never
caused a problem, and hardens and deburs the silver beautifully.
Time should not be the problem. Good Luck!

Lisa Weber

If you don't care for the sugar mess of coke, use Simple Green

I assume that sugar free Coke works too - no sugary mess.

I assume that sugar free Coke works too - no sugary mess. 

Yes, diet or regular, Coke or Pepsi. It doesn’t matter. Other brands
of cola probably work well too. It is the acid that does the trick,
not the sugar.

Letting the soda go flat is important because shaking up a
carbonated beverage is not a good idea and many tumbler closures will
not withstand the pressure. I once used coke that was not flat enough
and ended up with shot and a sticky mess everywhere…

Mary Ellin D’Agostino, PhD