Removing/stripping chrome from brass camera parts

Q. I renovate old cameras and need to remove the chrome on many of them. I have used polishing wheels to do this but think there SHOULD be a chemical I could use to do this w/o grinding/polishing the chrome off the brass body of the camera. Can anyone point me to a product or company that can help. Thank you.

A. Hi Chandos, hi Jurgen -- muriatic acid ⇦this on eBay or Amazon [affil links] will quickly strip chrome, but it won't do anything for the nickel which will usually be underlying the chrome. Stripping nickel requires either very strong, very nasty nitric acid, or specialized proprietary chemicals like Metalx (Ronatec.us) [a finishing.com supporting advertiser], so it might be better to take the parts to a plating shop for stripping. Good luck.

A. For small parts, the following will suffice. Using a car battery and heavy jumper leads placed well away from the two plastic buckets, one containing caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] and water, saturated solution. The other bucket has a 50-50 sulfuric acid water solution and a pint of glycerine added. The caustic bath uses a cathode of steel 10 sq. inches approx. The acid bath uses a cathode of lead. Use a strip of lead roof flashing 10 sq. ins approx. The caustic bath is used first to remove the chrome. Takes a minute or so. Rinse the part well; then place in the sulfuric bath to strip nickel. Takes a little longer or until effervescing stops on the part. I will let you figure out the correct way to place the electrical wires. Only works one way. Same for both strips. Be careful. Wear rubber gloves ⇦this on eBay or Amazon [affil links] , goggles ⇦this on eBay or Amazon [affil links] , mask, and have running water close by. No responsibility accepted.

Thanks Mark. But have you done this with brass parts rather than steel parts? I am surprised to hear that this wouldn't ruin brass, which is an alloy prone to dezincification in concentrated caustic or concentrated sulfuric acid or strong electrolytic currents.

As Mark implies, these are dangerous chemicals; they really should only be used by trained professionals in an industrial facility, not by amateurs at home.

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

Keep doing as you were before with good old elbow grease. Acid along with mixing different chemicals is highly dangerous to trained or untrained novices going about this. I knew one fellow that was blinded in one eye doing a job such as yours and he was a professional plater.

A. Try 125 ml/l HCl at 125 °F.

A. When people say they want to strip "chrome", what they usually mean is they want to strip a nickel-chrome finish. Removing the chrome is relatively easy, but removing the underlying nickel is not. You should try to obtain a proprietary stripper made for that purpose from a supplier like Metalx (Ronatec.us) [a finishing.com supporting advertiser]. Good luck with it.

Finding a plating shop to apply black chrome plating shouldn't be that hard; a number of shops do it.

Q. Ted thank you!

Yes I am attempting to remove both the chrome and nickel, right down to the underlying brass. I am hoping that we will not find it necessary to use a chromate conversion prior to finishing with a black finish. Any assistance in this regard is greatly appreciated. Sincerely Phillip

A. As long as you are willing to go to a plating shop rather than doing it yourself, I don't know why these parts could not be black chrome plated. Brass can be chemically blackened, but unless the area is embossed so you have a 'relief' look, the blackening might wear off very quickly. Paint or powder might adhere, but they would be inferior to black chrome plating.

A. Your parts are most likely hard chrome plated and if these parts are considered critical components, should be re-plated with the same type of coating that the manufacturer originally specified. Hard chrome can be removed using caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] solution or sulfuric acid solution, depending on the thickness. Your parts most likely have less than .001" thick, either process is acceptable. You should send parts to a plating company to have the coating removed.

A. There are two common ways to remove chrome, Maunie. The first is hydrochloric acid (muriatic acid ⇦this on eBay or Amazon [affil links] ). The second is reverse current alkaline stripping--essentially, putting the part into an electrocleaning tank.

The first is fast and simple, and does not generate hexavalent chromium, but can attack the substrate. The second will not attack the substrate but is more complicated, and it generates hexavalent chromium which is an environmental problem.

What is critical to remember is that these procedures remove chrome metal, but consumers commonly use the parlance 'chrome plating' when referring to decorative multilayer copper-nickel-chrome plating. So after the chromium is stripped, you may still have nickel plating--which doesn't look a whole lot different to the untrained eye. So sometimes the chrome was quickly and easily stripped but they don't know it :-)

Q. Mr, Shintaro's site shows the results of his stripping chrome camera parts in preparation for painting them black. He doesn't tell which chemical he uses but the results are very good indeed. I would appreciate recommendations for any product that could strip chrome off brass this well.

A. Our readers have already answered the question several times so we've appended these inquiries to a similar thread.

Here's the thing, again though --

Chrome is not usually plated directly on brass; the plating is usually nickel plating then chrome plating. Nickel looks a lot like chrome to the layperson, but chrome is pretty easy to remove. Muriatic acid (dangerous stuff) will remove it. The nickel is harder to remove and requires proprietary strippers or really nasty nitric acid based strippers. The chrome must be removed or the paint won't stick right; the nickel can probably remain as long as it's good and clean, and primed.

Some people feel that light sandblasting is the best approach as it removes the chrome and scuffs up the nickel.