Preparing acid copper brightener

A. Hobby beginner electroplater here. I have found an easily available (in the US anyway) brightener that works for me using sulfuric acid based room temperature bath. MiraLAX, which is a laxative found in any drugstore or Walmart. It is basically polyethylene glycol powder and worked great for my needs.

I too searched for a long time for a brightener. Dosage is approx. 1 teaspoon per gallon, but I have not determined the optimal amount since it worked for me right away. FYI 0.2 volt.

A. With respect to the question on brighteners, polyethylene glycol has been mentioned. The laxative recommended (in fact all PEG laxatives) has quite a large molecular weight, i.e., 3350. What is recommended for plating seems to be lower molecular weight, i.e., shorter chain molecules.

The other brightener I've read about is "Dalcin(R)" aka sodium saccharin. It can be purchased in bulk from eBay quite cheaply.

I understand the chef analogy to requests for proprietary formula ... but the analogy seems to fail when we forget the original poster isn't telling the chef to release his recipe, the OP is asking ... and asking politely it would seem.

Thanks
Doug

A. I am just getting started with copper electroforming and have found the many YouTube videos by Jason Welsh most informative. He discusses the use of Polyethylene Glycol (PG) as a brightener and points out a practical issue. Over time you will find that you need to keep topping up the PG in your tank. Eventually this will no longer restore brightness to your pieces. The remedy for this is to pass the entire solution through a carbon filter. After filtering it would be prudent to check the pH and adjust the acidity as required.
Jason's video "Electroforming Brightener Glycol":

I realise that this relates to Electroforming rather than Electroplating but think that it is still usefully informative.

Thanks Jeremy, that is very practical & useful information for non-commercial use, as well as for third-world-ers without access to established brightener supplies.

Still, there are some differences between artistic electroforming and commercial electroplating. For example, there is little or no need for ductility in electroforming, but it is often crucial in electroplating.

Another issue that hobbyists usually do not need to worry much about, but which is critical for commercial platers, is an 'equilibrium process' -- for them it is not just a matter of the plating on the component functioning well, but that the bath stays perfectly balanced.

Luck & Regards,

A. You may begin by consulting a variety of reference books and reading old and current patent literature. Then you can go to the laboratory and test out each of the formulation components until you arrive at the components needed and the quantities required of each. Or, you could call a supplier of proprietary materials who has already done the above and more and would charge a fair price for the benefit of their research and knowledge by selling a proven material.

You might surmise that I am involved in the sales and/or manufacture of proprietary chemistry and you would be right. Do you tell a chef to give you the recipe, you don't want to eat at his restaurant? Do you ask a doctor for the formulation for a drug? Why do you expect to get proprietary knowledge for free?

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Hello Gene, you're certainly right that some knowledge is proprietary, and can't be expected for free!

But sometimes people ask because they don't know what is generic information vs. what is trade secret. People unfamiliar with how the industry works in the western world probably assume that you electroplate things by mixing together basic chemicals as they were taught in science class.

In fact, "home-brew" is required when a technology loses its champion -- as happened with cyanide zinc plating when Dupont abandoned us, and as happened with magnesium finishing techniques when Dow abandoned us; but it's also required in much of the third world where there is no commercial distribution of western plating processes.

If we look at the reason for a worldwide patent system -- "to incentivize the advance of technology for the good of mankind, we must grant temporary financial benefit to those who put in the work" -- each side should be able to respect the other's side.

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

A. Hi, Eric. I understand. Unfortunately, I and the majority of readers don't know the answers anyway because they are trade secrets, and you won't find current information in text books these days. In some cases, those brighteners can't be created by simple mixing of raw materials; rather they must be "synthesized from precursors", similar to how plastics are made from crude oil -- which rules out "home brew" anyway.

A possible path forward may be to look through old plating books for generic brighteners from "back when". Lowenheim's "Modern Electroplating" from 1942 includes a 2-page discussion of generic brighteners, and it references many different articles on the subject, including many patents, most of which are surely expired by now. (Access to patent info is generally free and reasonably easy these days).

It's not as simple as "try this" though, because each of the referenced possibilities has a list of operating parameters, disadvantages and warnings, etc. Here is an excerpt from that discussion to show the flavor of it:

Best of luck!

Regards,

Hi Ted,
Thanks for the honest reply, I will try that as a matter of some urgency.
Really enjoy your site and will visit frequently (even if only for being inquisitive by nature).
Cheers

A. Have you tried Thiourea [on eBay or Amazon]? Use it sparingly. Be very careful, this thing will give you pancreatic cancer and damage your bones.

A. Urea 1 g/l and glycerin 1-2 ml/l

A. Hi, Saravanababu. Without brighteners, the copper plating will grow as rather large crystals in the way of rock candy. These tend to be rather soft; and porous (because there will be 'holes' where these large crystals grow to meet each other); and dull because of their rough topography.

Brighteners tend to deposit with the electricity, and thus to coat the highest current density areas first and, by so doing, promote the growth of new crystals elsewhere instead. The process leads to more, smaller, harder, less porous crystals, and bright deposits. Good luck.

Regards,

A. Hi, Komal
Sorry, I don't know the exact answer to that, or even if there is a universal answer, because different proprietary brighteners might react differently to temperature. But I do know that some brighteners "oil out" (break down into ineffective oils) at temperatures as low as 100 °F, maybe even lower. Sorry, but I don't know the composition or temperature resistance of the proprietary acid copper brighteners. Good luck.

Regards,

A. Hi Omid,

Usually is some polyalkalyene glycol related chemistries.

Regards,
David

A. Hi Rameez. We appended your inquiry to a thread which explains brighteners for acid copper plating. Good luck.

Regards,

A. Surprised no one mentioned molasses. That's right, blackstrap molasses from the grocery store.

A. Hi Brock. Molasses is a 'brightener' for copper plating; as such, a small amount is added to the solution in the plating tank. Molecules of the brightener are drawn to the high current density areas of the component being plated and tend to slightly shield it away from further plating. By doing so, the plating is more even in thickness, and more adatoms form, for smaller, less porous, harder plating.

Regards,

A. Hi again. A copper pipe is not a great anode, but it may be useable for hobby purposes. Stripped copper wire is a bit better because it's purer and better preserved.

One of your issues is that there are a hundred variables in plating, so when you have questionable anode material, questionable cathode, questionable power supply, questionable chemistry, questionable instructions, are getting "mush" ... and you now want to talk about questionable brighteners ... it's a pretty deep hole to climb out of.

I would start by getting some small pieces of brass sheet, get them spotlessly clean by scrubbing with a pumice solution and toothbrush while wearing gloves, and try to plate them, because brass is the most plateable substrate, whereas we have no idea whether your particular graphite + PVA article is plateable. The way to find out and narrow down the list of things that could be causing the problem is to successfully or unsuccessfully plate something else. Good luck.

Regards,

  Thank you again Ted, Yes I thought it could be any of a number of individual or cumulative factors! Going to start afresh, thank you for your advice, best regards. Brockie