plating, anodizing, & finishing Q&As since 1989
Streaky Brass Patina Problem
I am currently doing a very large casino project and have done a bit of patina work in the past,the problem is, is the brass and copper sheets are fairly large and wiping on b.c.antique black tends to leave the lines where the B.C. overlaps.I've run across this before but on smaller pieces I just burnish it out. Is there an easier way to apply the chemicals as to not leave streaks on the panels,there are a lot of them and my co.is counting on me to pull this off .
- Portland OR
Rick - I would suggest using an immersion method. Get a tank big enough to hold the sheet, and submerge the piece until it has the desired finish. Keep in mind that the tank doesn't have to be enormous - it may be built just deep enough to lay the piece flat inside and be completely covered in solution (kind of like a big tray). Good luck.Dan Brewer
chemical process supplier - Gurnee, Illinois
I have created patina on copper sheets in a tall skinny tank where sheets were suspended by one edge, then edge metal above solution that was not patinated, got sheared off. This solved problem of variations across sheet.
Also tried applying patination chemicals using an automated spray head, with slightly overlapping spray pattern, which worked across the sheet while it was moving on a conveyor underneath. Would expect brass to respond equally well. I found that mechanically sanding the surface dry produced the best activation, also.W. Carl Erickson
- Rome, New York
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