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Preventing immersion deposition of copper on steel tubing

November 28, 2011

When we plate copper with cyanide copper electrolyte it will not plate copper insides of the tubes of metal chairs. Why?

We recently developed new acid copper bath with composition,

copper sulphate ⇦this on eBay or Amazon [affil links] ---> 225 g/l
sulfuric 98% --->30 ml/l
chloride --->40ppm
cuprobrite 310 make up--->10 ml/l
cuprobrite 310 part A--->0.5 ml/l
cuprobrite 310 part B--->0.5 ml/l

But this plates lots of copper insides of the metal tube (inside the legs of steel chairs). But it's not strongly adhered to the steel & washed with water. The problem is when we put these in a nickel plating bath this non-adhering copper contaminates the nickel bath. Copper plated outside of the tubes gives good, bright & level coat to the steel and it is properly adhered to the steel.

We first use copper strike bath; it plates copper on chairs properly without plating inside of the tubes (legs of the chairs) but when we put it in a acid copper bath it will plate copper not only outside of the legs but also inside these inside copper washed very quickly hence contaminate other nickel and chromium baths.

Can someone tell me how I can implement good acid copper bath with above chemicals without plating the inside of the tube.

Harsha Rathnayake
- Gampaha, Sri Lanka

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Hi, Harsha.

There are many different possible approaches. The simplest would be to not plate copper at all -- just go directly into nickel plating. Is there a reason that this is not satisfactory to you?

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 29, 2011

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If the cyanide copper is eliminated, you will need much better pre-treatment, since this also cleans and activates the surface. I think that is a mistake to use acid copper on tubular steel unless you also plug the ends of the tube.

If you continue to plate copper before nickel, I recommend that you continuously remove copper from your nickel bath with a dummy cell operating at 1-3 amps per square foot. This is often done with V shaped corrugated steel plates, but is also done with high surface area cathodes. It is done in a side tank or if you have an overflow sump on your nickel tank, it can be done in this sump.

Lyle Kirman
consultant - Cleveland Heights, Ohio
November 30, 2011

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Hi,

Pls use stopper so that the solution doesn't enter the hollow pipe.

Praveen Kumar
plating process supplier
Mumbai, India
December 1, 2011

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December 20, 2011

IT IS VERY DIFFICULT TO PLATE TUBULAR ITEMS.
TED SIR IS RIGHT GIVE 15 TO 20 MICRONS IN NICKEL.
IF YOU WANT HIGHER PROTECTION YOU CAN GO FOR TRI NICKEL.
I.E., SEMI BRIGHT + TRI + BRIGHT THEN CHROME PLATING.
REGARDS.

Ajay Raina
Ludhiana, Punjab, India