Brass cleaning issue

[MT257]

I recently threw some 30-06 cases into the tumbler this brass was shot one time before sizing/depriming. I have had it in the tumbler for 8 hours and I have noticed areas on the cases appear black or darkened. What causes this and how can it be prevented?

 

[Orange Dust]

More info??

 

[MOOSE39465]

I had the same problem. After switching to stainless wet media all my problems went away.

 

[MT257]

More info??

Walnut media. Not sure what other information to include...

 

[Orange Dust]

Try clean untreated corn cob with Dillon polish, or switch over to wet with SS media like above. Walnut is only to clean, not polish. Guessing black is from the oils in the Walnut.

 

[marchboom]

I recently threw some 30-06 cases into the tumbler this brass was shot one time before sizing/depriming. I have had it in the tumbler for 8 hours and I have noticed areas on the cases appear black or darkened. What causes this and how can it be prevented?

I've never had brass appear black or darkened. Have no idea what is causing it.

My method is as follows: Deprime brass then soak in a solution of 1pt of water and 1/4 teaspoon of Lemishine for 45 minutes. Depriming allows the solution to get inside the cases and primer pockets (no trapped air).

Note: Allowing the brass to soak for over an hour OR adding more Lemishime to the water will cause the brass to turn a pinkish color.

Allow the brass to dry then tumble in walnut shell media for 1-2 hrs. DONE!

I use
Zilla Ground English Walnut Shells Desert Blend from Amazon. It will not get stuck in the flash holes.

8 hrs in a tumbler is overkill unless the brass is really tarnished.

Good luck.

 

[Dosh]

MT, were there any black or darkened spots on the brass prior to tumbling. Perhaps the sizing lube is the culprit. Like Moose, no discoloration when tumbled in the SS pins as long as not over tumbled and not too much Lemishine.

 

[MT257]

MT, were there any black or darkened spots on the brass prior to tumbling. Perhaps the sizing lube is the culprit. Like Moose, no discoloration when tumbled in the SS pins as long as not over tumbled and not too much Lemishine.

Nope brass looked clean and spot free before tumbling. Would wiping sizing lube off the case prior to tumbling help prevent this?

 

[DUSTY NOGGIN]

if 8 hrs didnt get lube off ? im still wondering what it is .. got pics ?? does it wipe off ??

if i am ever excessive with the lube (imperial wax) i will throw a old dryer sheet in there .. which will absorb all that up plus take some powered garbage with it

 

[MT257]

Here is a picture of the coloration. Some cases are better than others.

 

[dok7mm]

Depending on how long you've used your batch of media, it's most likely to be saturated with carbon residue from your previosly fired & tumbled brass. Also it just wears out.

I use a 50/50 mix of walnut and small screen corncob, it cleans and polishes up very well in 1-2 hours. When my dryer sheets show a lot of black, I dump that batch and start over.

I keep a bunch of old, large bath towels to remove any dust left from tumbling. Just a three-way fold, along long side, then roll back & forth for a few minutes. I don't want that dust, especially carbon dust, in my annealer
or scratching my dies.

Because I shoot a lot, I now buy bulk media from blasting media companies. A 40# bag of each will last 2-3 years and saves money over the smaller jugs.

 

[MOOSE39465]

Something is reacting to the brass. Possibly from the media itself. Try to put some dryers sheets in when you tumble. Hopefully it will help.

 

[ShtrRdy]

That's weird. I've never seen tumbling do that. But then I tumble for 1.5 hours and use the Lyman treated media.

 

[Legionnaire]

I have seen something that looks like that one time. I was tumbling in well used (dirty) corn cob media and I accidentally used a piece of a NEW dryer sheet to catch dust. Something in the dryer sheet caused the carbon residue to stick to the brass. Lesson learned.