Acid Copper Plating Problems Q&A

A. Hi Malik.
You've given us no info to go by yet, and unfortunately there are many possible causes for any given defect. But guessing from the photo and no data, maybe these components are zinc die castings full of porosity? If it is not a die casting, and you are sure the mechanical finishing was inspected before plating, my next guess would be floating grease being redeposited on the part as it's lifted out of the cleaning tank.
Luck & Regards,


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

A. If the anodes are phosphorized copper as they should be, then the anodes are polarized. Take them out, remove the bags, replace with new clean bags, put back in. The black sludge is "hazardous waste". Robert H Probert Robert H Probert Technical Services Garner, North Carolina A. Service anode or change to new. John Hu - Singapore

A. Don,

The first thing you need to do is a complete analysis of your solution to check that your bath is in balance. Carbon treating without knowing what you are treating for is pointless.

If your analysis shows that the copper and acid levels are correct then do a Hull Cell and play with the brightener levels until you get a satisfactory plate in the mid range current densities.

If all else fails ask the chemical suppliers if they can help, they are usually extremely helpful and can normally offer the services of an expert to try to sort out your problems.

I must admit that it is a long time since I played with acid solutions, normally dealing with cyanide or pyrophosphate systems these days so I apologise for my vagueness but there are simple rules to apply to a situation like yours: Analyse, Hull Cell, expert, dump.

If your production pressures are high sometimes it is more economical to dump the solution and start again rather than have a long down time while you try to sort the problem.

Hope you get your problem sorted soon.

A. You will "lose" your ability to carry current when the amount of copper in solution has become too high raising your ratio of copper sulphate.
Titrate the solution and see if you are within spec; if not, the easiest solution is to cut the bath. You can test it out first in Hull Cells.

A. Hi Don in my opinion...the problem is about the anodes. the brightener may be makes the anodes surface passive. take away the anodes...cleaning the bags and the surfaces thanks Arda Baþaran plating - Turkey A. This is classic anode polarization and most likely due to too high copper sulphate [on eBay or Amazon]content and possibly low temperature. Geoffrey Whitelaw - Port Melbourne, Australia

A. Hi Don,

The chloride level in your bath is low. The level must be above 40 ppm and below 80 ppm for satisfactory passage of current.

Do this and let us know.

Regards,

A. Hi Don,
I believe your problem is TOO much chloride -- are the anodes getting a white coating on them? If so, take them out and scrub until you see clean copper.
You may have to do this a few times.
I had this same problem in my electroforming tank.

A. The total concentration of copper sulphate and sulfuric acid should not be higher than 300 g/l otherwise you get polarisation.

A. Everyone has valid advice. Basically they have told you to check everything since you could have too much or too little. The most valid advice is to call your supplier. They generally will offer to run an analysis of your bath at no charge (this is included in what is called customer service) and since you are having a problem they should then offer their learned opinion of what the corrective measures are.

Before everyone jumps on and comments I would like to clarify that periodic analysis by the vendor is not a substitute for having the capacity to have routine analysis done on premises or locally, nor that every time you have a small problem go running to your vendor (enough people do to give me days when I wish cell phones had not been invented). But the vendor does have product specific knowledge to their formulations as well (usually) as having people with a wealth of knowledge. Also your supplier should be sure you have a Technical Data Sheet for the products and processes being purchased, analytical instruction and a trouble shooting guide.

One point I forgot, if you are using "city water" in your acid copper, you should have the necessary chloride without adding any. If you have been making large additions of water and not of acid or salts that would tend to raise the chloride level (maybe). Get an analysis and test panels done!

A. I am sure that your problem is high copper sulphate if your bath solution about 100 liter only you must to get out 25 liter from your solution and put 25 liter ionized water good luck

A. Dear Don,

At first I am not sure what is really the issue in your plating bath.
At first you need to analyze the bath very regularly specially if it's a 24-hr operation. Depletion of additives and other chemical varies in every panels loaded in the bath and that is why there should be a regular routine analysis.
1) firstly, how is the current density, is it calculated as per number of panels per rack.
2) how is the chloride content and how is the color of the anodes, black phosphorized film should be seen on the anodes.
3) what is your process, is it pattern or panel plating (for PCB process), should the color of the bath is greenish then it should be contaminated much with more organics on it. maybe there is a need to do carbon treatment and check TOC.

You need to investigate further and the assistance of the chemical supplier also will help a lot to troubleshoot the issue.

Thank you very much.

Regards,
Allan

A. Don,

your copper bath, no amps but voltage because copper anodes are polarized (if you see your anodes are dark color that means polarized)

pull out you anodes , change the new bags, new proper type of anodes, check your chemistry.
check the rectifier, check the current to anode and cathode bar.

A. Hi cousin Jerlan. I think your problem is more properly described as excess copper rather than excess sulphate per se; there is no place for sulphate to come from during operation, but dissolving anodes can contribute to excess copper.

You will read above that two responders do suggest your action of bailing out some of the solution and replacing it with water -- but I think this was suggested as an emergency fix, not as an operational routine.

The thing to investigate is whether you are using phosphorized anodes. These are intended to solve just this problem. After that is assured, then you might consider reducing the number of anodes and, if necessary, making a small and controlled chloride adjustment.

Regards,

A. Hi Gopi. Please mail some pictures of these "dots" to mooney@finishing.com for posting here because it is not clear if they are roughness, pits, discolorations, or whatever. I assume they are pinhead size or smaller?

Durney's wonderful Trouble in Your Tank? [affil link on Amazon or on AbeBooks ] starts from the first paragraph with the reminder that the only way this can happen is because something changed, so your first step is to figure out what it was that changed :-)

This is a place of camaraderie and we have postings from several different people with the name gopi nath. Please give us a fuller name if possible so we don't confuse you with others. Thanks!

Luck and Regards,

A. Hi Raj. Sorry, but your question is a bit too vague for me to be able to comment properly. Are you saying that you trying to do copper plating from 230 g/l copper sulphate and nothing else -- no sulfuric acid, no chloride, no addition agents?

Or are you implying that you are using a properly formulated bright acid copper bath, and gradually adding brightener, only to discover that as you move from dull to bright you start losing coverage? If so, can you tell us your chloride content? Brighteners and chloride work sort of symbiotically and sort of in opposition -- it can prove impossible to obtain proper plating while ignoring chloride level. Good luck and get back to us please.

Regards,

A. Sorry Raj, neither is satisfactory. As a wild guess the one which is offering complete dull coverage is purer and the other is contaminated with something which is brightening it.

You haven't told us what you want to plate and why, but the short answer is that you don't use plain copper sulphate -- that's for school science projects to demonstrate the science of copper plating, but not for actual industrial use.

Ideally you buy a bright acid copper plating process from a supplier, but if that is not practical for some reason, you formulate one from copper sulphate, sulfuric acid, a carefully controlled small amount of chloride, a wetting agent, thiourea [on eBay or Amazon], and a brightening agent like dextrin or molasses. If you can't get access to any books about copper plating, then the copper plating chapter of the Metal Finishing Guidebook is at least a good start. Good luck!

Regards,

A. Hi cousin Jessie. Two readers suggest bailing out the tank as the most practical immediate fix, but the bigger question is how you got there. You have to fix that, and studying this thread should tell you how :-)

But get back to us with anything that's not clear. Good luck.

Regards,

A. Hi Jessie,
Besides bath bail out, if your intention is to reduce Cu ion then you may use insoluble anode to run dummy plating till Cu drop to optimum level. If your intention is to reduce sulphate ion then you may replenish copper oxide instead of copper sulphate to minimize sulphate ion build up.

Regards,
David

A. Hi Molly. Please send a good photo of the panel to mooney@finishing.com for posting here. It's hard to photograph/see a mirror. If the copper plating is highly reflective, try to reflect a page of text on white paper onto your panel for the photo to help us see the distortion. Thanks.

Regards,

A. Hi Abdurrahim. If you are a hobbyist doing one antenna, try the following (from the Metal Finishing Guidebook 2012-2013):
199 g/L Copper Sulphate
30 g/L Acid
50-120 ppm Cl

If it's not bright enough to your taste add 0.0375 g/L thiourea [on eBay or Amazon] and 0.75 g/L molasses. Current density about 1.5-3.0 A/dm2.

But if you are a plating shop doing professional work you should probably be buying your acid copper plating solution from a reputable supplier and following their technical data sheet rather than playing with generic formulations. Good luck.

Regards,

A. I have dealt with this problem before. We maintain three full time acid copper baths. In my personal opinion this looks like a chemistry issue. Try running a Hull Cell to see if your bath is lacking in brightener/carrier. I run mine at 1 ampere for 10 mins and if you have a lack in the brightener system components you will see a shaded or pitted area on the panel. Add small amounts of the corresponding component (I.E. brightener or carrier or both depending on the manufacturer of the solution you are using) to the Hull cell. I start off with small adds around .1mL at a time and run another panel. You should see an improvement in the deposit. Continue until you have a nice even panel with no irregularities in the finish. You can convert the adds you made to the hull cell to the main plating bath, amount will depend on volume of the main tank. One other thing you can check is solution agitation. Acid copper baths require a lot of agitation. Most Shops use air agitation or jet agitation through inductors. Air agitation tends to consume more of the brighteners than jet agitation. Something to keep in mind. Good luck, I hope this helps.

A. You are seeing the result of organic material in the acid copper bath. It could be accidental, from the mandrel or other source, or it could be "deliberate" from addition agent for grain refining or brightening.

Carbon treat the bath, run a sample. Then, if necessary, start adding your addition agent in very small quantities. Don't over-add.

We'd like to give credit for this graphic explaining Ohm's Law (A = V / Ω) but see it on many websites without info of whose work it actually was :-(

A. Hi Anandh. Per Ohm's Law, A = V/R, so if the amperage has gone down when the voltage hasn't, the only explanation is that the resistance has increased, i.e., the conductivity has decreased.

There could be a number of possible causes, but without any other data, my first guess would be that your anodes become polarized over the course of the hour. Please search the site for "acid copper polarized anodes"

Luck & Regards,

A. Hi Luka,

I've seen acid copper plated parts defect, due to over brightener use in acid copper bath. Run hull cell panel and adjust the chemistry, and carbon treat if necessary or dummy the copper bath.

? A lot of variations in process. Tank material and chemistry of bath?

Ed. note: One of the graphics shows the chemistry of the bath and operating conditions.

A. It's a Acid copper plating bath in attacking

Solution ...
First use activated carbon packed in filter 1 gm/ltr, and running in tank minimum 4-6 hours.
And then dummy out at high current density.
Then bri.-0.01 ml/ltr part A
Part B - half of part A
Makeup - 0.1 ml/ ltr

? Hello Andy, I have a few questions for you before I give you any troubleshooting tips and remedies. When you run your hand over the copper plated surface, is it smooth or rough? Are your anodes bagged and if so, are they in good shape? There shouldn't be any holes in the bags.
The reason I ask if the surface is rough where you're seeing the crystals is that there is a very good chance the problem would be particulate matter in the bath. You will also want to make sure your filtration is adequate, with filters that are changed on a regular basis. Please let me know the answer to my first three questions. Thank You and good luck.

A. Hello again Andy,
I have to be honest with you in that I have never heard of the additives you mention for an acid copper bath. I guess I've been out of the business too long. I have worked for companies that had to comply with many mil specs and certifications, but I'm afraid I can't help you with this.