Where the
world gathers for metal finishing
Q&As since 1989


-----

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 relieved (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, Michigan

We have a small E-coat line in which we run antique brass almost every day without a problem. You might want to check your predip to make sure its not too strong or bypass it totally. It also may depend what vendor you are using or even what type of oxidizer you are using.

Chris Faeth
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 sulphate based system?

Scott Schnau [returning]
- Grand Rapids, Michigan
 

---

Hi,

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

I couldn't be more pleased.

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

Good Luck,

Ken Fefferman
- Harwood Hts, Illinois
 

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

Chris Faeth
Los Angeles California USA