Stripping chrome plating from metal

A. Hi Phil. If the nozzles truly are silicone, no problem, as it is highly resistant to everything used in a plating shop (silicone caps and plugs are often used to keep plating and plating chemicals out of selected areas during the process).

But stripping chrome, re-activating the underlying nickel plating, and plating with black chrome are a really really tall order for a D-I-Yer, and finding a shop willing to take on this project may prove difficult.

What you might consider instead is a black tinted lacquer to go over the chrome. "Spray chrome", although it's a misnomer and is actually just a 3-layer paint job, consists of priming with a base layer, followed by a mirror coating layer, followed by a protective top coat which can be clear or tinted. Perhaps you can talk to a supplier of spray chrome supplies about the possibility of applying just the black tinted lacquer to your existing chrome.
Luck & Regards,

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

A. Hi Max,
May I suggest you go to the archives and have a look-see at topic12044 ...(another motor cyclist, another chrome problem).
If you don't mind 'wading' through a lot of data, you'll eventually find some answers ... but thanks must go to the intelligent dawgs many of the repliers show.
Anyhow, that will sure save me lots of time if you do that!
I wish you success with your restorations ... a Black Shadow Vincent, perhaps? If I recall correctly, didn't a side car version hit the world's speed record of + 140 mph many years ago .. in South Africa !

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

 Many thanks and very entertaining, most of which I don't have a clue. What I do know is that I'll take the stuff to the shop ... I don't want my dog drinking all that waste!

A. The quickest way to remove chrome and the copper/ nickel undercoat is dilute sulfuric acid (as used in lead acid batteries. You can soak with periodic inspection and rinsing or you can speed the process up using electrolytic action, e.g. connect the item to be stripped up to 12 volt supply and use a piece of lead as the cathode (similar size to item being stripped) also connected to supply positive. If you have it the wrong way round the lead plate will fizz instead of the item you want to strip (reverse connection. However, the soaking method will work for most decorative plating finishes in a short time. Be careful with acid use long rubber rubber gloves ⇦ this on eBay or Amazon [affil links] and apron ⇦ this on eBay or Amazon [affil links] and eye protection (goggles ⇦ this on eBay or Amazon [affil links] ).
Good luck,
Mike Tew
- UK

? Hi Mike. I don't think soaking with periodic rinsing and inspection will remove the nickel and copper because neither nickel nor copper is soluble in sulfuric acid -- have you actually tried it as opposed to having read about it? Yes, you can remove it in acid with electricity, but it is usually better to use an electrolyte or process which selectively dissolves a coating without attacking the substrate. Sulfuric acid will attack the steel faster than it attacks nickel and copper. Still, for a down and dirty approach, it's interesting :-)

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

A. Hi Mostafa. You haven't introduced yourself, so I'm not sure if you work in a plating shop and have tanks available, and training in acids. But a relatively quick dip (probably not more than 2 minutes) in HCl / Muriatic acid will remove the chrome without affecting the nickel plating much. Good luck.
Regards,

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

A. Hi Nimesh. Sulfuric acid is unlikely to work well. A dip in HCl or electrolytic stripping in caustic are the two common methods depending on thickness, substrate, etc.

Please search the site with the term "strip chrome" and you'll see some 40 threads about removing chrome from all sorts of different parts and substrate metals; your parts and substrate metal may be covered by one of those threads. Or give us full particulars and people can help. Good luck.

adv.

Working in a plating shop as you do, when you say you want to remove chrome, that's probably what you want to do. But other readers should recognize that decorative chrome plating is actually always nickel plating followed by chrome plating ... and the nickel is about 98-99% of the plating with a very thin topcoat of chrome plating. So when they say they want to remove the chrome what they usually want is to remove the nickel as well, but sulfuric acid and/or hydrochloric acid will not remove the nickel plating.
Regards,

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