Tumbler turning pieces black


i recall someone asking a question recently about their tumbler turning pieces black….i could not find the original post…

i saw this video tip on instagram, on Metalsmith Society’s feed…i dont think the link to video will post correctly…

Metalsmith Society shared a post on Instagram: "When your work is turning grey-ish black in your tumbler try this recipe to clean the barrel and your media: 50/50 Distilled white vinegar and water. Tumbler for 20 and rinse. Then fill with water and a...

if not, here is where to find it on instagram


Tumbling with flat coke seems to work. I tumbled with not so flat coke once and things got exciting real fast…Rob


Wow. That’s a first. My inexpensive HF tumbler turns somethings black but that’s from the cheap tub breaking down I think. I tear everything down and clean it all and start fresh when that occurs.

I may try the semi-flat coke route just to see what happens.


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Put on a rain coat if you do…Rob


you are tumbling too long of time. clean tumbler w/ Tb spoon backing soda and soap . when using tumbler, tumble for 10-15 minuets or so.

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Run a teaspoon of citric acid through the tumbler with some extra water. It will clean the pieces also with no harm.

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This happened with the black rubber barrels. After much cleaning, I learned the barrels were deteriorating. Solved it by purchasing new barrels.

I had some issues a while back with my tumbler, originally a rock tumbler with the black rubber barrels. I had pieces coming out really dark, and not just a coating in black stuff - the dark haze barely came off with sanding. It couldn’t be “just” rubber flakes off the inside of the barrel.

Eventually learned that steel has a chemical reaction with aluminum ions. Rock tumbling grit is often aluminum-oxide, and perhaps there was a residue of it left behind when the steel shot went in.

Everything got washed, I did try the flat cola trick, but I also built some new barrels to keep my various mediums completely separate. Haven’t had any troubles so far!

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I had the same issue and asked Tony Davidson (@therealtonydavidson on Instagram - GREAT TUTORIALS!) she said it is often an issue with the water, switch to distilled water and add some Sunsheen Burnishing Fluid (dilute mixture).
Also be sure to keep your shot clean, I’ve used a dash of Bar Keepers Friend (find at any grocery or Walgreens, etc.) and water with the shot in a tupperware container instead of the tumbler, as it is abrasive, and I didn’t want to damage the barrel.

Super Sunsheen Burnishing Compounds - RioGrande

Amazon.com: Bar Keepers Friend Powder Cleanser 12 Oz - Multipurpose Cleaner & Stain Remover - Bathroom, Kitchen & Outdoor Use - for Stainless Steel, Aluminum, Brass, Ceramic, Porcelain, Bronze and More (2 Pack) : Health & Household