"Dark" Brass After Tumbling?

[A.M.]

Using SS media + Thumbler + citric acid for tumbling brass. Hot water rinse after.

For some reason, it gets really dark once it dries. Looks gross.

Thoughts?

[Maltese Falcon]

Why use the citric acid? Just use dishwasher soap IMO.

Citric acid is used in leaching metals from RCRA classified hazardous waste under the CA STLC process (I work at a Enviro lab).

Probably what is staining your brass, redo it with just the soap.

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[tiller]

You used too much citric acid....

It is the best way to clean over soap... There is no comparison BUT.... If you use too much you can etch your brass (probably what you did) pics would help...

You should just use lemi shine as it is a more watered down version of citric acid and takes alot to etch brass...

[J-cat]

In order to have nice shiny brass, you need the right ratio of acid to soap. Too much soap will make your brass plum colored. Too much acid will etch your brass and it will look sandblasted. The correct ratio for Thumler's Model B is .5cc of Lemishine to two flat tablespoons of dawn. That will yield perfect looking brass. Deviate from that and your blass will suffer.

[Colt562]

Yeah I say to much citric acid as well. I only let mine sit in a mixture of lemishine and soap for about 5 minutes. Moving it around the whole time.

[tiller]

In order to have nice shiny brass, you need the right ratio of acid to soap. Too much soap will make your brass plum colored. Too much acid will etch your brass and it will look sandblasted. The correct ratio for Thumler's Model B is .5cc of Lemishine to two flat tablespoons of dawn. That will yield perfect looking brass. Deviate from that and your blass will suffer.

As you stated this is for lemi shine...

If this recipe is used with citric acid you should probably use about half the amount of citric acid than lemi shine