Corn Cob Media Turned Green

[Marco Califo]

I have been tumbling batches of brass in my FART. Something different happened in the latest batch. The corn cob media turned green. This media had been used several times, but was yellow when I put it in with 500 LC 5.56. That brass had been spilled in my garage and was swept up and cleaned, including a wet Tumble with pins and blue FART juice. So, put that fairly clean looking brass into the dried tumbler, with the reused media. I kept checking the brass and tumbled at least 6 hours. Shined up OK. But now I think I need to toss that media. Any ideas on what caused the color change?

[Metal god]

No but as mine gets dirtier it changes color . I think one could call it green . Not the same as yours but not to far from it either .

[Marco Califo]

Thanks. I put a bunch of capfuls of NuFinish in that media, a cap or two before each 1000 piece run.

[50 shooter]

You only need a cupful or two, you might be adding to much polish and that's why you're having issues with it.

[Marco Califo]

I just sorted through that last batch of brass and it left a bluish residue on my hands, that I promptly washed off.
That media got a lot of use tumbling big batches of brass. I guess when the color changes, and polishing had already slowed way down, that is a clear indicator the media is used up and needs replacing.
That media has been transferred to a plastic jar for disposal. I am going to tumble the last batch again with clean corn cob.

[Shane Tuttle]

Doesn't look all that bad, if you ask me. I do think after reading your follow-up post, I'd recommend wearing nitrile gloves when handling the media. And, if it's at the point residue is left on your hands, it's time to address it. If you're the frugal type, you can use Dawn or equivalent, to wash the media. It's loaded up with gunk and will take a couple of washing cycles to get it back up to snuff. Personally, I think it's a pain and not worth the few dollars saved.

[hdwhit]

Probably nothing more than the media getting saturated with oxide from the brass.

But, corn cob media is derived from corn and if the media gets wet and is allowed to stay wet, the media could be starting to ferment.

In either case, it is time for new tumbling media.

[Marco Califo]

Corn cob media is derived from corn cobs, not grain corn. During the U.S. Civil War starving confederate troops made corn cob soup. They lost the war. No yeast smell in mine, it smells of auto polish. Now, if you would like to try making home brew from mine, I would suggest adding fermentable sugars, excess fruit, hops if feeling fancy, and a good dose of live yeast. Good luck with that.

[Double Naught Spy]

During the U.S. Civil War starving confederate troops made corn cob soup. They lost the war.

LOL, are you stringing random bits of information together or are you drawing some sort of conclusion?

[Marco Califo]

Well, Double Naught Spy,
Let it ferment, then,
Catch as catch can.

[Double Naught Spy]

You seem to be drawing a conclusion that the Confederates ate corn cob soup and them losing the war is somehow tied to that. No fermenting necessary.

[Marco Califo]

I was poking fun at hdwhit bringing up fermentation. I do not believe corncob media is fermentable.
You are correct that I strung together bits of information leading no where, consistent with hdwhit's fermentation angle. Sorry if that confused you.

[44 AMP]

If it is made of/from organic material (plant/animal matter) it can rot.

Fermenting is a special form of that, as bluing is a special form of rust. One can still have rot without fermenting, if the conditions and materials for fermentation are not present.

Still, I think your answer might be closer to home...

This media had been used several times, but was yellow when I put it in with 500 LC 5.56. That brass had been spilled in my garage and was swept up and cleaned, including a wet Tumble with pins and blue FART juice.

IF I remember art class correctly, yellow and blue make green!!!

[Marco Califo]

After tumbling with pins, I drained, and poured off the now black blue FART juice directly into a toilet. I rinsed the brass, and used a media separator and strainers, pouring back and forth. The tumbler body was stored open end down overnight indoors (very dry air). It was dry to the touch. The media was around a gallon in volume. I do think the media picked a lot of tarnish, which caused its effectiveness to degrade in that last run.

[gwpercle]

Originally Posted by Marco Califo

Thanks. I put a bunch of capfuls of NuFinish in that media, a cap or two before each 1000 piece run.

Adding too much Nu-Finish or any other Liquid car wax will "Load Up " the media and stop it's cleaning action .
Keep the media as dry as you can and it will last the longest ... when it stops cleaning just dump it and change it ... adding more liquid isn't how to fix it ...
All media wears out and corn cob being the softest wears out the quickest .

For my money Midway USA Treated Walnut Shell polishing media last the longest and is the best value ... as long as you refrain from adding liquid car wax to it ... wet media isn't good ... you want nice dry media .
Gary

[reynolds357]

Mine starts out green because I put the green Lyman junk in it.

[The Happy kaboomer]

The best value media is "Lizard Litter" from Petsmart.........Ground walnut hulls/corn cob. A 10 lb bag is only a couple of $$$.