Letter 12072

E-Coating Oxidized Brass 

We are currently trying to develop an e-coat process (to replace clear lacquer) over the top of antiqued (oxidized) and reliefed (highlighted) brass. The problem that is being experienced is the dissolution of the antique. Do you have any suggestions to successfully e-coat oxidized brass and yet maintain the original look?

Scott Schnau
- Grand Rapids, MI, USA

We have a small ecoat line in wich we run antique brass almost every day with out a problem. You might want to check your pre dip to make sure its not to strong or by pass it totally. It also may depend what vendor you are using or even what type of oxidizer you are using.

Chris Faeth Highland Plating Company Los Angeles California USA

I appreciate your feedback. What type of oxidizing chemicals are you using on the brass? Is it a selenium / copper based mixed acid or is it a nickel sulfate based system?

Scott Schnau
- Grand Rapids, MI, USA

Hi,

In the past, we heavily brass plated(45 min racked) our pewtar alloy castings, oxidized, and hand relieved our medallions on a linen wheel with wet pumice yielding a beautiful antique finish which all to often bled cyanide. I became so frustrated with this problem that I put in a small Ecoat line with a "brass dye" solution.

I couldn't be more pleased.

Now we oxidize the unplated alloy, relieve, and then ecoat to a beautiful "brass" finish which does not affect the antiqued highlights and shadows. There are many other benefits. We can obscure the antiqueing but only after 15 microns of thickness. Remember ours is not clear but rather brass dye added.

Good Luck,

Ken Fefferman
- Harwood Hts, IL

We are using AT800 Antique Black. The ecoat bath we are currently using is from Technic. I believe the AT800 is a copper base solution but I'll have to check the TDS.

Chris Faeth Highland Plating Company Los Angeles California USA

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