Stripping nickel plating from aluminum -- Q&A, Problems & solutions

A. Hi Chris. We appended your inquiry to some earlier discussions on the topic which you may find helpful (nitric acid and water may be all you need). But there may be other suppliers who offer commercial immersion strippers in Europe if that interests you.

Apologies, but we can only print your list of ingredients for commercial strippers and their functions if you cite the published places where you found each of them (textbook name, name of article, patent, suppliers technical data sheet, SDS, etc.)

The reason is that we don't know internet posters (if I'm not wrong, the name you are using is fictitious), and if you contribute this, and a 2nd person adds that, and a 3rd person says thus and so ... somewhere along the line someone's knowledge may have been illegitimately obtained (a disgruntled former employee posting with a fictitious name, etc.) and the posting might comprise anonymous crowd sourcing of industrial espionage. :-(

Reverse engineering is usually considered fine when done right, but certainly not when publicly posted by an essentially anonymous group :-)

Sorry again, and Regards,


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

A. Hi again. Indeed, that is a 1986 patent, now long expired, so you are welcome to use it. The preferred embodiment is supposed to work -- because a fully disclosed workable answer is the payment the public is entitled to receive in return for bearing the costs of protecting the patentee for 20 years. But even still, we can't publicly discuss the formulation of proprietary products.

I understand that you prefer to not use an electrolytic stripper, but sulfuric acid electrolytic strippers are discussed on this page if you find no workable alternative. Good Luck,


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

A. I suggest you go back to the local plating shop and teach them how to strip in the above mentioned nitric acid solution. I would strongly suggest that you do *not* mess with concentrated nitric and the hazardous waste you will produce once you load it with nickel.

A. The large gunsmith supply companies carry a nickel stripper that works quite well. The parts that need to have the nickel removed just need to be immersed in the liquid. It's the best way I've found to remove nickel without a lot of polishing but it only comes in one gallon quantities so it's not meant for large jobs.

Just to let you guys know. I have successfully removed a lot of chrome and nickel with the techniques listed here. I'm lucky enough to have access to a large supply of sodium Hydroxide and Nitric acid. I have been using them for years at my Job. (with the proper training and safety gear). After buying an old motorcycle I was look into into ways of removing the chrome, then nickel then polishing up the aluminum. and WOW...it worked great. That is AFTER I destroyed a small pc. trying to sand and pick it off.

THANK YOU VERY MUCH.

Brian

A. 50% tech grade sulfuric acid (66 degree sulfuric acid) and 50% water using electricity will take off your nickel without hurting your aluminum. You can use a battery charger ⇦this on eBay or Amazon [affil links] as a rectifier. If the part has copper on it depending how much build is on the part it should remove it also. Nitric acid will do the job the same way without electricity -- make sure you don't put steel in nitric acid, bad* chem reaction. good luck

A. Nickel can be stripped from aluminium using the Laybere solution; this a mixture of 3 parts of conc. sulfuric acid to 2 parts of water. It is used at room temperature with an applied anodic current of about 40 A/ft². Your container will depend on the size of your parts, but I see nothing wrong with a glass beaker [beakers on eBay or Amazon [affil links] if it is of the correct size. If you need something bigger, use a PVC, polypropylene or rubber lined steel tank. As far as the processing time is concerned - it all depends on how much nickel you have to remove and what the temperature is. Now that you have been told what to do for your project, go and do some experiments for yourself, but don't forget to give due reference to the sources of your information as it would be most unethical to claim the credit yourself.....

A. I doubt if it will work. It will also depend on what the aluminum alloy is.
Look at concentrated nitric acid. One notch below red fuming. Regular nitric that most people would use commercially has too much water in it. The part has to be absolutely dry when you put it into the acid. Note that it will slowly absorb water from the air and you will at some point have etched parts. ⇩

OK, my head was somewhere other than firmly attached to the neck. The procedure that I talked about was for removing EN from steel. My bad.

In another letter, an author talked about using 12% sulfuric acid with peroxide for removal of EN. Do not remember the substrate.

A. James, the sulfuric acid/peroxide mix is pretty potent and will take off most metals - I have used a similar formulation for dissolving both nickel and copper, but it will chew up any metal substrates if you're not careful!

A. You can use electrolytic etching -- this process is much safer than H2SO4. Slightly acidified nickel sulphate solution can be used as electrolyte, object=anode, platinized titanium or stainless steel=cathode.

Good luck!

A. You will need an ammeter to tell you the amount of current being passed. You will also need an accurate clock to tell you the time spent; I suggest a stopwatch. Your process looks basically sound, but I suggest you check with your supervisor before doing it - he knows your abilities and the abilities of your classmates and the equipment. Furthermore, he is responsible for you!

A. Hi, cousin Lee.

It would be dangerous to conduct experiments except under a lab hood, and without wearing the correct PPE experiment, or without proper training and supervision. People on the internet, who you don't know and who don't know you, your facility, or your training level, can't be sure about the safety of a proposed experiment. As Mr. Crichton noted, your supervisor is the one who must be asked these questions and who must supervise you during it. Good luck, and stay safe.

A. Hi all..

If you got NiCr to be stripped,

you shall remove the Cr with sodium carbonate/washing soda ⇦this on eBay or Amazon [affil links] anodic at 3 ADM...after that only, you strip the nickel by sulfuric 60%.

To strip nickel from Aluminium disk, you need 70% dilution from 68% nitric acid by dipping process. The nickel will be removed, the fumes might be a bit danger so be careful. To create process inhibition you may add sulfuric acid at 5% dilution.. but the more you put it will slow the process.

A. Hi Jan
Yes the nickel plating must be stripped and re-done. We added your inquiry to a thread on the subject which suggests a number of different ways, but a proprietary nickel stripper is probably safest. Good luck.

Regards,

A. Dear sir if you use nickel stripping, the part will be little much eroded in microns. Again you have to polish it. After this on aluminium they are doing zincating process, then ENP or Bright nickel. If zincating solution is not well maintained this problem occurs. It's not only due to cleaning ... better to try Electroless nickel on zincated surface. You'll get better adhesion and corrosion resistance too due to phosphorous content in ENP. It has 3 grades: use high phosphorous grade.

A. Dear Jan,
One day is too long for nickel strip using nitric acid. Few minutes should be enough. Clean the part from oil, immerse in nitric acid in well ventilated area for 5 minutes and check. Continue with 5 minutes immersion cycle until the deposit will be dissolved.
Good luck!

A. Hi Terry. Trevor's postings were from 17 years ago so I don't know if he'll see yours and follow up, but in this context "concentrated" means 'as concentrated as possible/practical', i.e., 98% / S.G. 1.84 / Molarity 18.4.
Some people might say concentrated sulfuric acid is only 96% for some practical reasons, but when you're diluting with water that way, whether the acid was theoretically 98% or 96% really doesn't actually matter. Good luck!
I hope you and other readers are attentive to the safety warnings he repeats 3 times in the course of the discussion.

Luck & Regards,