OXIDATION

[HOTSHOT]

What would cause parts plated with COPYCHROME to turn black. I have to keep removing them from my motorcycle for polishing with a cotton wheel every month or so. I have parts that remain inside out of the weather and they don't do it. All parts were 'chromed' for at least one hour at the appropriate current and temperature settings and they came out in excellent condition. I've tried keeping them polished with car wax and recently I coated them with a product called 'Liquid Glass', a clear paint sealer. They still oxidize, is there anything I can do to prevent this? Ken

[wop1969]

Did you clean the parts down to bare metal befor plating (I.E Sand then down real good to remove anything)?
And did you plate them right after sanding leaving no time for surface rust ?

[HOTSHOT]

I sanded from coarse up to 2000 grit wet/dry paper. Then buffed on 2 wheels to get a chrome-like shine. Then I dipped into SP Degreaser at prescribed temperature for allotted time. (The aluminum parts went into the Zincate solution to preserve the pure clean aluminum finish.) Then directly to the copy chrome bucket for 1 hour at appropriate amperage and temperature. When the parts came out, I buffed them on the wheels again ending with the red rouge for a deep chrome-like brilliant shine. I polished them further with Mothers carnuba wax. They looked great for a while, then the steel and aluminum parts all started to turn black. That is where I am now. Any ideas Ken

[wop1969]

hmmm Ill have to think about this one. Gimmie some time and ill try to come up with an answer. In the mean time call caswell phone support and see what they might have to offer as far as help.

[HOTSHOT]

I'll do it Monday. Thanks

[showroomexpress]

hotshot - unless I missed something it doesnt appear that you copper plated the pieces before copy chroming them . please let us know if /how you get this resolved. good luck,

[HOTSHOT]

The copy chrome kit doesn't require a base coat of copper. I followed the procedure of sanding and polishing the pieces to a brilliant shine. Then a dip in SP Degreaser, rinse with distilled water, then into the Zincate solution for the aluminum pieces. Then to the copy chrome bucket for an hour. They all came out great after polishing. It took about a month for the pieces, steel and aluminum, to start turning a dark color. Anything I've kept inside is still fine.

[showroomexpress]

hotshot. I was so perplexed about your situation I called caswell and spoke to customer service, he read your post over the phone and agreed that it was a lack of copper plating that was causing the problem, Have you tried to call them yet? Please keep all us copy chromers posted. Thanks........... John

[HOTSHOT]

I find that interesting because the copy chrome kit is designed to work as one step without copper. The instructions state that the first step for aluminum is to imerse it in the zincate solution and go directly to the copy chrome bucket. For steel, all that is needed, according to the instructions, is to polish it, clean it with the SP Degreaser and put it in the copy chrome bucket. If they are saying that I need to copper plate it first, it is contrary to how they are advertising the copy chrome system. I've been intending to call them but I've been distracted with ongoing situations at work. I'll try to contact them on Monday. Be assured, I will post what I find out from them here. Thanks for responding. Ken

[dadkar2]

Here's a thought.

I know from experience under typical room conditions and over extended periods of time, nickel plating will develop a darkish cast when it oxidizes. This is under room conditions. I also know that nickel electroplate is going to be somewhat porous, so under extreme conditions the substrate oxidation will also show through, whether it is copper or steel. Obviously steel will be worse because it will show through as iron oxide and spread, eventually pushing off the plating from underneath. All this can be accelerated by extreme environmental conditions.

Unfortunately in your application, nickel plating may not be suitable for harsh environmental (heat, moisture, salt, etc) applications. Remember that copy chrome is simply nickel with additional trace elements (eg cobalt) that give it the blue cast of chrome. But it is NOT chrome and does not have the durability of chrome. The reason chrome plating is applied to nickel is to provide the surface durability and protection needed to withstand difficult environmental conditions.

The only thing I can't explain is why waxing doesn't retard the process. That is unusual. I would expect that it should. Are the parts heated to extreme during use (eg engine parts)?

A copper pre-plating will likely slow it down a bit, but it's not clear that it will stop what you are seeing.

Eventually, repeated polishing of the copy chrome will wear through the plating. You might want to consider doing good ol' chrome plating. Personally, I wouldn't set up chrome plating at home, but there are many daring souls out there that do.

There are certain grades and treatments of electroless nickel that claim similar corrosion resistance to chrome. I don't know if Caswell offers these and I don't know if they provide a cobalt tinted formulation either. But there are other forms of chrome (trivalent vs. hexavalent) that are environmentally safer to use.

Kind regards,
Ken