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Ted Mooney, P.E. RET
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for Metal Finishing 1989-2025
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Fouled Electropolishing Coil
Q. We're having difficulty maintaining temperature in our electropolishing tank so we removed the heating coil - a Teflon spaghetti type. It was plugged with a greenish crystalline material that was acting as an insulating layer preventing adequate heat exchange. My questions are: (1) what is the solid material (most likely a salt of nickel and/or chrome but which ones?) and (2) what's the easiest way to dissolve it without resorting to mechanical means (those tubes are delicate)?
Milt StevensonPlating Shop Engineer - Syracuse, New York
2007
A. Milt- please be more specific. What metal(s) are you electropolishing? What is your bath chemistry?
Jon Barrows, MSF, EHSSC
Independence, Missouri
2007
Q. OK OK more info .... we're electropolishing traditional 300 series stainless steel and the electrolyte is a conventional heated phosphoric / sulfuric syrup!
Milt Stevenson, Jr.Plating Shop Engineer - Syracuse, New York
2007
2007
A. It might be a monobasic nickel phosphate salt. Something like Ni2H4(PO4)2. That's an educated guess.
Try some aqua ammonia. Some people call it "ammonium hydroxide."
Dave Wichern
Consultant - The Bronx, New York
I had my environmental operations supervisor try Dave Wichern's ammonia
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eBay or
Amazon [affil links] trick and he was pleasantly surprised - it seems to do the trick! Thanks Dave!
Milt Stevenson, Jr.
Syracuse, New York
2007
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