Quote:
Originally Posted by Steve in Vermont
As to comments that Citric Acid "attacks metals", I have never heard of this before (regarding brass). Most information I have states there is no damage, that the Citric Acid "passivates" the brass and helps fight tarnish (making it more resistant to corrosion). Perhaps there is some confusion with ammonia, which is harmful to brass. If anyone has any reference to Citric Acid being a problem please let me know. I'm only one of many using this cleaning process. And it doesn't leave my brass shining new, just clean.
|
All acids react with something, but what specific materials they react with and the intensity of that reaction varies.
Who does what to whom can be found in chemistry books and databases.
For metals specifically, use metallurgy books and databases.
Brass is an alloy of Copper and Zinc and the tarnish is oxides of the two base metals.
Citric acid "attacks" Brass by removing the Oxygen from the tarnish,
leaving the base metals behind. (This is good - Not bad.)
Many moons have past since I looked this stuff up, so I'm not sure if Citric acid actually passivates Brass, but tumbling would remove the passivated layer even if it does, so if you tumble your Brass after washing, add some Amonia-Free polish to your tumbling media to protect the exposed Brass.
John