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Rough deposit in vertical plating of aluminium alloy wheels

I am working in Chennai based private firm for the past 11 years looking after electro plating plant of steel rims. Recently we have started to plated aluminium alloy wheel plating. While doing vertical plating of aluminium wheel, we observe rough deposit at the bottom of the wheel. Till now we are plating steel rim horizontally. Can you pl explain how I can avoid this rough deposit while plating aluminium alloy wheels.

S G SUNDARRAJAN
PLATING SHOP SUPERVISOR - CHENNAI, TAMILNADU, India
2007

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There are a number of steps in plating an aluminum wheel, S G, including zincating, cyanide copper or electroless nickel, nickel plating, chrome plating, and maybe more. I think the first step is to figure out which plating step is introducing this roughness. Lacking that, my only guess is that the tank is not sufficiently agitated so it is cool at the bottom and the plating is burning in that area. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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Mr. Sundarajan,
I think Ted is right. Other than temperature and agitation, please have a look on the uniform concentrate of zincating and bright dip, if any. Be sure even of rinsing water and rinsing process, since you are plating vertically now there are the chances of having contaminated water at the bottom of wheels which may be leading to rough/striated/sharp demarcation deposits. Good Luck!

Shafiuddin A. Mohammed
metal coating shop - Dubai, United Arab Emirates
September 14, 2008