I’ve been using the Caswell system for just over 2 years now, I finally got everything worked out and was getting beautiful results. Then One day someone else in the shop tried to plate something, and its created some serious problems.

Pictures A1-5 are a copycad plated bolt and a bright zinc plated gascap, they were the last parts I plated before the solution got contaminated.

Pictures B1-2 are parts that I was trying to bright zinc plate after contamination, I used the same process: glassbead, rinse, muratic acid dip, rinse, SP Degreaser, rinse, plate 20-25min @ 1.3-1.4A/10sq in.

Part B2 was so bad that the plating would flake off if you barely touched the part.

I noticed a red oily film on the top of the plating solution, when I came in the next morning, so I decanted my plating tank into empty distilled water gallon jugs, filtered it through a coffee filter (twice), then ran it through a charcoal filter (Brita).

Then I cleaned the plating tank thoroughly with a scotchbrite and distilled water, cleaned the anodes, added the recommended amount of brightener, checked the PH, heated the tank up to 110-115*, and took a piece of virgin sheetmetal, went through the same prep process. I also polished one half of the plate on each side, and only dipped the tank in muratic acid half way. I figured I’d have 4 different finishes/etches to try an narrow down the problem.

I plated it for 15 minutes @1.4A/sq in, and it seemed dull, so I doubled the brightener and bumped it to 1.6A/sq in for another 5 minutes (this has worked in the past). Those pictures are C1-2.

You can see the bright zinc around the edges of the part, but as you move toward the center it gets dull and gritty.

Any ideas on where to go from here?

Thanks,
John

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