Trying to oxidize silver w black max, it’s turning red brown

I’ve been using Black Max from Rio to try to oxidize some silver pieces that have small 18k gold details on them. The oxidation process is coming out grey/black, but with spots of reddish brown as well. I’m wondering if it’s fire stain showing though? Which I thought I sanded off. Or something’s else?thanks!

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Are you using a steel-end brush to apply it, as Rio recommends?


No, I thought that was only to oxidize gold, which I only want to oxidize the silver part. But, I’ll try it, thanks!

You don’t need the steel brush for silver since it oxidizes quite readily by itself.

I haven’t tried to oxidize copper with Black Max, but your guess as to what you are seeing seems logical. What kind of silver alloy are you using?

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It is sterling silver, thanks!

Is it possible you have some polishing compound still on your
piece? I’ve found that I’ve had this problem sometimes when I’ve
had to use bobbing compound, which is very greasy. I learned to
make sure I put my pieces in a heated ultrasonic to get the
compound out of the little hiding places, and that seemed to solve
the problem with the splotchiness and color changes.


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I have used Black Max for several years and it goes deep true black for me every time. I started using this because the color I was getting from LOS was unreliable. This is a lot of steps, but I like high drama… Mwah Ha Ha!!

  • I tumble my piece first
  • then I use a soft brass brush on it (just a quick brushing)
  • then I toss it into a small bowl of hot water and Dawn (or dish soap you have handy) and go over it with an old toothbrush to remove any possible trace of oil or polish that may be on the brass brush… Rinse
  • then I apply Black max with small flat artist brush, let dry and repeat if you want very black patina.
  • I rub back the high relief design with silicone polishers on my flexshaft. from medium to fine.
  • I want my patina to stay, so I use Renaissance Wax as a final.

Excellent advice. Don’t forget to wear your neoprene gloves to keep from getting any Black Max on your skin.

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Thanks Linda-I’ll try all of this!

I use nitrile gloves from Costco. Are you sure you meant neoprene? I would think they would be terribly thick. I have used it without gloves at all and it didn’t do anything to my skin, but I don’t make a habit of it. :slight_smile:

Purple Nitrile gloves - there is a very nasty acid in Black max, and you should be very careful - read the label.
Judy H

Yes on the nitrile. Mine are white translucent. I don’t know that color matters as long as there is protection. Mine are also from Costco.

I agree on the color, but neoprene is scuba diving suit material. LOL!