Letter 1806

Stripping electroless nickel

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we are looking for a solution that will strip electroless nickel from copper and brass base metal parts without affecting the parts. any suggestions?

wilbert e. medina
- bayamon, puerto rico

We use Fidelity 3136. It will strip 150 microinches of high phosphorous electroless nickel in an hour without affecting the underlying copper plate or be-cu or brass substrates. II am sure other vendors have similar products.

This is an alkaline mixture that runs at 200 F and contains ethylene diamine and nitrobenzoates, so waste disposal may be a problem. We use very little since our reject rate is small and we can afford to drum it for disposal by a licensed hauler.

Bill Vins microwave & cable assemblies Mesa (what a place-a), Arizona

Metalx advertises at this site and has as good a set of strippers as anyone. Good people also.

James Watts
- Navarre, Florida

My recommendation is to use Enthones EN86. It is develped for use in removing Hi-phos En . It also strips electroplated sulfate and Sulfamate Nickel. I used to make up only what is required to strip a particular volume. these strips do hold a particular value of nickel. Maybe 4 oz /gal.

Any strip not respected will damage the base metal.

What I have learned in stripping EN off copper and especially brass. Activate the Nickel well. Do not drag the activator in to the strip. DO NOT boil the strip. Once boiled the inhibitors are gone and etching will occure.Maintain some solution movement. The nickel turns black, the inhibitor is dark brown. do not confuse the two and sample clean a piece or two when you think the parts are stripped. The inhibitor is difficult to remove once dried. Stripping EN off substrates and the parts looking like they have never been plated is the goal. Good luck

Todd Huehn

Please also see our FAQs on Stripping of Electroless Nickel.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey