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topic 33997

White mark for Ni rack plating


I have trouble about white colour on contact point for Ni-rack plating line. My product is a plate about 5 cm X 5 cm, and found white colour( high gross ) at the area of jig contact point on edge on product.

Who can advise me?please.

Viruch Jamroonwong
Plating shop - Thailand


What you're experiencing is not uncommon with nickel plating. When designing a plating rack, you need to ensure that your rack tip is as unobtrusive as possible. The key is that the rack tip is large enough to carry sufficient current but small enough not to leave a large rack mark.

Also, make sure your rack tips don't have plating buildup on them. Large nodules of nickel left on the tip will inevitably lead to a large rack mark that will grow as the nodules grow.

Hope this helps.

Daryl Spindler
decorative nickel chrome plating - Nashville, TN


Mr Viruch.

White spots occur where jigs connect with an article due to Poor connectivity and poor throw. The basic solution must be properly balanced. If possible Chloride as Nicl2 should be 60 GPl or 70 gpl. Boric acid must be maintainbed around 45 to 48 gpl. Secondly : carrier adds must be adequate to maintain a good throw. Excess brightener adds are avoidable. Temp and agitation must be adequate per data sheet . The jig contacts must be sufficiently well sprung to maintain a tight contact. Reducing current for the first 30 percent of plating time and then plating at usual current by gradual increases will help with the marks.


Asif Nurie
- New Delhi, India

With deep regret we
sadly advise that
Asif passed away

on Jan 24, 2016

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