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Nickel Rack Plating: air vs mechanical

May 20, 2009

I work in a job shop with two Watts nickel baths. In the past, we have used the baths separately: 1) rack work with air agitation and 2) barrel work with mechanical agitation. We are considering changing both baths to mechanical agitation.

I would appreciate any comments regarding use of a mechanical (vs air) nickel bath to do rack work. Our jobs range from nickel on steel to copper-nickel-(tri)chrome. Quality, cost, efficiency, and ease-of-use are all important factors.

Thank you for your time and thoughtful comments.

Mark Smith
Lab Tech - Minneapolis, MN, USA

Hi, Mark. There isn't one universally best answer or the others would never be used. But mechanical (cathode rocker) agitation does not provide nearly the degree of agitation and mixing that air agitation does.

An increasingly popular approach is eductors. In this approach, the plating solution is pumped thru venturi-shaped nozzles. It gives lots of agitation (as much as air) without the air bubbles racing towards the surface and entraining solution and carrying it out of the tank in the fashion of Champagne bubbles. It is significantly more expensive than air agitation, but probably is the wave of the future due to less entrainment and better housekeeping.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
May 21, 2009