Conductive paint/lacquer Q&A for electroforming

A. Hi Vance. That subject has been discussed here a dozen times. In addition to this thread, please see topic 57992, or use the search engine to find everything. But brush marks are largely a question of how much thinning is done. In order to avoid brush marks, premium brass chandelier manufacturers may dilute their brass lacquer so thin that seven sequential coatings and dryings are required.

One approach mentioned by Goran Budija in topic 55101 is to mix bronze powder into highly thinned nitrocellulose lacquer. We can discuss various types of metallizing approaches, but sorry, we've learned to no longer post brand or sourcing suggestions (why?)

Luck & Regards,

A. Hi Peter. Even professional platers have occasional problems with peeling & blistering (lack of sufficient adhesion) ... so nobody will be able to tell you whether or not zinc paint followed by copper sulphate followed by electroplating will offer sufficient adhesion for your plastic models. But in general, copper is more ductile and less highly stressed than nickel, so I think your plan is good.

But your idea of zinc rich paint ('cold galvanizing' paint) followed by copper sulphate just might be a terrific -- inexpensive, readily available, easy -- metallizing approach for the electroformers here! Thanks!

Luck & Regards,

A. People have developed some new systems for metallizing printed circuit boards which use carbon (or graphite?). I don't believe that the price of the technology has much to do with the cost of the conductor. It's like the cost of developing a new drug; the research is what takes most of the money.

A. David,

We have tried a number of different conductive paints and have mainly used Electrodag from Acheson Colloids. I believe they have a nickel based paint which would be cheaper than the usual silver base. Your problem will be in using cyanide copper as the alkaline cyanide solution is a good paint stripper. We have always used acid copper or silver over these products.

Regards

Graphite Conductive Paint

on eBay or

Amazon

(affil links)

A. Some 15 years ago we did plating over items like flower buds, insects, and leaves. We made the surfaces conductive by "painting" on a carbon colloidal suspension which was marketed under the name of "Aquadag"

I believe the supplier, whose name I cannot recall is now defunct.

It was necessary to plate an undercoat of copper, and only acid copper was suitable. We intended to try a sulphamate bath as alternative, but the customer passed away before we could. (He was a retired professor of botany).

Maybe you could source an equivalent to Aquadag. It worked really well.

A. This type of coating is widely used to "bronze" baby shoes by coating with a conductive paint such as Aquadag then electroplating.

Indium - tin- oxide (ITO) (mixture of In₂O₃ and SnO₂) is a transparent (colorless) conductive oxide. It is deposited on surfaces by PVD techniques but would also be useful as a conductive powder.

A. If you're attempting Cu - Ni - Au for thin film processes, then PVD (sputtering), vacuum evap., or a combination of either w/ Au up-plate is the only way to go for adhesion under high temperature. If you're attempting this coating on an organic such as a plastic, you may want to look into what the PCB industry uses for plated thru holes. Specifically, palladium catalyst activation processes with following plate-up. For this latter technology, contact your plating chemical supplier (I use Technic). Good luck

A. Dave,

As Don mentioned earlier, this process is used in the bronzing of "baby shoes." However, the applications are limitless.

A. Hi Wayne. For a start, try our FAQs on the subject. Gold plating onto previously chrome plated items is the world's easiest plating because all the hard stuff (polishing, buffing, cleaning, activating, copper plating, and extremely corrosion resistant nickel plating) has already been done to very high quality standards. Gold plating of organic materials will be much harder, involving sealing, metallizing, copper plating, and nickel plating before the gold plating. Good luck. Aloha.

Regards,

A. Like many of the postings you have already received, when plating non-metallics I have found that you must use an Acid Copper system. The Copper paint can be made by using a nitrocellulose based lacquer and filling it with very fine copper powder which you can buy from a Lab supplier (for small quantities at exorbitant prices) or in larger quantities from any reasonable Metal supplier.

One of the secrets that has not been mentioned is that once the non-metallic surface has been coated with the "conductive paint" it must be left to "cure" and the "Cure" time depends on how thick the "conductive paint" is. My experience is minimum cure time is 24 hours but the longer the better (up to 7 days is sometimes needed).

A. Anybody who wants to electroplate non-metallics should find a copy of "How to Electroplate for Fun and Profit by Warner Electric Co. 1950 ==>

It describes the following process.

A. Hi Rob. Yes, its doable. As Tom Pullizzi alluded to early on in this thread, similar products are used these days to metallize printed circuit boards in lieu of the older and more traditional process of tin/palladium activation followed by electroless copper plating. Although the chemistries are proprietary, you can probably find good hints from white papers on google, and solid information from patent searches. The search term "direct metallization" may be helpful. Good luck.

Regards,

A. Hi Bo. The Warner Electric booklets suggested by Donald Warner are probably good ones if you can find a copy (availability is on-again / off-again). Sorry, but we can't recommend suppliers in this no-registration-required forum (why?) -- it draws spammers like fleas, with some of them even posing as satisfied customers and posting with fictitious names :-)

I've probably said this too many times, but when onesy-twosy plating of natural materials, it is an art more than a science, and pleasing results will require artistic ability -- I have none, so my advice is of limited value :-)

Luck and Regards,

Hi, Renee. Please try your best to express your question in terms of what has already been said in rhe postings before yours so we can keep moving forward. Repetition is the kiss of death for threads. Thanks!

A. Hi, Aaron. If preserving fine really fine detail is essential you might think of two-part silvering rather than conductive paint. You will lose no definition at all. This is what is used to metallize masters for vinyl records, and was used on videodisks (today PVD vacuum processes are used to metallize CD and DVD masters).

Regards,

A. Hi, Aaron. 2-part silvering has been around for centuries, long before dual nozzle spray guns were available, so I'm confident that it is possible.

The highest resolution, however, is obtained by spraying while the object is on a spin table to thin out the coating, so any compromises you make will limit the resolution somewhat. Even a children's toy spin art table might (or might not) help. Good luck.

Regards,

A. Hi, Michael.

Plating on plastic probably should not be your first attempt at electroplating because it is more difficult than plating on metal. Plating something with iron should not be your first attempt, either, as iron plating is more difficult than most metals because of its propensity to oxidize to a higher valence state that it can't be plated from. You can't use salt water as the electrolyte because ions of the metal you are plating must be soluble in the electrolyte, and iron will not be soluble in salt water. Please see our FAQ on "How Electroplating Works" as well as our FAQ on "How to Electroplate Organic Materials", and start with something simpler :-)

If you are just trying to get an item plated, as opposed to starting a hobby, there are jobshops listed in our Jobshops Directory that can help you. Good luck.

Regards,

A. Hi, Ross.

While almost any substrate can be electroplated some way or another -- probably including by the methods you propose -- the issue is usually inadequate adhesion. There are probably few applications where shortcomings in adhesion will more quickly become evident than exterior automotive parts. These items should be molded of plating grade ABS, as most OEM grills and bezels are, and then it will be possible for the plating to properly adhere in the punishing environment that cars encounter (because ABS is a multiple component plastic from which one of the components can be etched away, leaving a sponge-like surface for great "keying"). Good luck.

Regards,

Thanks for the suggestion to use plating grade ABS. My google searches for this however show that ABS must be injection molded. My hobby uses silicone molds and cold - poured urethane resin. Injection molding is beyond me. Cheers
Ross

A. No, Gale, oxides like that are not conductive. But we appended your inquiry to a thread which may help you get on the right track. Good luck.

Regards,

A. I am using MG Chemicals Total Ground spray to coat clay sculptures for electrotyping. So far so good. I am totally new to all this, but I have enough electricity and chemistry to understand the variables. I am using homemade electrolyte. I want to keep the cost down. This stuff is meant for creating a grounded work surface, so it is highly adhesive and highly conductive.

Q. Hi Ryan

Can you supply more info on the homemade electrolyte that you use?
Also where do you purchase the MG Chemicals Total ground spray from?
I want to use small pieces of glass and stuff from nature, Do you think your method would work for this?

Thanks so much for any info you can provide.

Judy

Hi, Judy. Hopefully, you'll get more info on the homemade electrolyte and an opinion about the method.

You can buy MG Chemical Total Ground from Amazon or use your search engine to find it. This site is possible because supporting advertisers provide it for camaraderie and technical information exchange. It's certainly no problem if people prefer to buy from non-advertisers -- but we can't ask our advertisers to pay the costs of maintaining distribution info here for their competitors :-)

Regards,

A. Hello,

Recently I came across a new process of silver spray. With this any non-conductive surface can be silver plated and the finish is extraordinary. It is a chemical process and a lot of people are moving towards it since cost is not too high and at the same time not much infrastructure is required as compared to vacuum metallization and PVD. This can give effects like gold plating as well.
You must try one of those they are really good and inexpensive.

A. Hi mohammad gharib. Copper electroplating is a process which operates in accordance with Faraday's Law: electrons are pumped to the cathode with a power supply, and positively ions migrate towards the cathode where they re-combine with those electrons to form atoms of metal. But electricity follows the path of least resistance, so it will probably prove difficult to electroplate into foam, as all of the buildup will be on the outside rather than into the pores. Please investigate electroless copper plating, which I think has a much better chance of success; and technology was developed for through-hole plating of printed circuit boards which may help you. Good luck.

Regards,

Q. Thanks Ted, but it has been proved for years that with the aid of some kind of colloidal graphite or carbon-black coating, it is possible to induce conductivity to such polymeric materials and making them plateable.

I'm now seeking for an appropriate conductive colloid coat.

Regards

A. Hi again. Yes, of course you can use colloidal graphites to induce conductivity and metallize non-conductors. In the circuit board and plating-on-plastics industries this approach seems to be supplanting the traditional tin/palladium activation followed by electroless plating. You should be able to get these from any of the major plating chemistry providers like Atotech, Macdermid, Surtec, etc. If you can't commercially buy those proprietaries in your location, you can at least read their patents and white papers for a good understanding of their chemistry.

But please slowly read what I was talking about, which is the difficulty in the electroplating step of getting plating into the pores of the foam rather than just glomming up on the outside; for this reason I believe you will find electroless copper plating a better way to start than graphites. Best of luck.

Regards,

Dear Ted,
your kind attention to my question is greatly appreciated.
Just to be noted that in this process polymeric foams with reticular structure are currently used.
Thanks again.

Hi again. Please look into the proprietary copper plating solutions used for thru-hole plating. They use large molecule brighteners that can't fit into the through holes, with the result that everything but the holes gets covered with these brighteners which tend to shield plating from occurring, while plating is able to happen inside the thru-holes because no brighteners fit into the holes. It is perhaps possible that this will help you get plating deep into the pores of the sponge rather than glomming up on the outside, as is its normal propensity. Good luck.

Regards,

A. Hi Jayanta. Such questions are hard to answer because in truth you can do nearly anything with nearly anything ...

Had Van Gogh tried "Starry Night" with a lump of cooking charcoal on brown kraft paper and it might still would have been a reasonable success. But in my opinion, artists & craftspersons shouldn't try to prove they can do passable work with ill-suited materials that way -- instead they should aim for exceptional work with optimal materials. So to answer your question in that sense, no, metallic copper paint is not the right metallization approach.

If your work is strictly decorative, not a circuit board or an electroform, and you want to start from a paint-like material rather than two-part silvering or circuit board metallization technology, I'd look into Aquadag, Electrodag, Sierra Silver, or another product designed specifically for the purpose. If you just want conductivity, with no plans to electroplate it, there are many products made for optimum conductivity. Please explain what the substrate is and why you want to metallize it. Best of luck.

Regards,

A. [Consider] this conductive paint: GRAPHIT 33. Good for Cu electroplating in CuSO4 solution. Made in Europe. Price varies between 8 and 20 Euros. Regards.

A. Hi Camson, you have to walk before you run. Please put a piece of well cleaned brass or copper into your rig and see if plating occurs (the plating probably may not stick properly, but at least you'll know some early basics like whether the rectifier is working). If you've never successfully plated anything before, we might waste time talking about your metallizing lacquer when it may have nothing to do with the problem :-)

What is your anode made of? What is the voltage? What is the approx. surface area of the object? Thanks. Good luck.

Regards,

A. Hi Cameron

Ted is right but also;-

Lacquers are non-conductive. To make them conduct you add metal powder But there must be enough metal in the dried layer for the particles to be in contact with each other or there will be no electrical pathway. That means a lot of metal and as little lacquer as practical.
Also copper oxidises very easily and even more so when it is a fine powder so it is not a very promising metal unless you can clean it after painting.
That is why most conductive paints are based on either silver or graphite

A. Copper plating on plastic or non-conducting surfaces is not very difficult but you need to commit to doing the right thing. Silver or copper or nickel filled epoxies work very well. Best to use a thermoset epoxy instead of a thermoplastic. The later usually peel or don't hold up to the chemistry. The epoxy as a thicker paste, say 2500 cps should be 65-70% filled or the conductivity will be too low and plating will be compromised. If you thin and want to spray them then thin with MEK and avoid thinning with acetone ... that affects working life of the spray mix. We have done millions of substrates using the silver filled epoxy. Test conductivity of the surface over a 1-inch distance conductivity for a layer that is 0.0002" should be just a few ohms. Higher values mean the ink is too lean in silver or copper. If using silver then you don't need activator but if you use copper or nickel you will need to use a Pd or Sn catalyst.

copper sulphate baths, high acid low metal can work quite well. Many PCB types from Atotech, or Macdermid, or Uyemura work well. Drop the current down for best results.

Patrick

A. Hi Raphael. Yes, you can certainly metallize with copper or graphite instead of silver, but you can't expect operations that are specialized to silver (like reducing it to metallic form with sunlight) to work on copper or graphite. You need to take it from the top, not just substitute.

I'm not sure what role the sour whey plays in that 1852 recipe, but I doubt that you can simply skip that step; but whey should be easily available and relatively cheap in health food stores. It's simply the liquid that's left over when you curdle milk. Good luck.

Regards,

A. Hi Qertusa. I'm fairly certain that it is do-able -- it's a truism that virtually anything can be metallized and plated. But whether it would be satisfactory depends on the application, and one of the toughest requirements is obtaining sufficient adhesion..

Copper-nickel-chrome plating of plastic automobile grills, for example, requires outstanding adhesion to hang onto the ABS in blazing sun and frigid cold, and despite abrasion from carwash brushes and spit gravel, etc.

Regards,

"Standards and Guidelines for Electroplated Plastics"
by American Society for Electroplated Plastics

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi Salem. Electroless copper isn't much used anymore except on circuit boards / printed wiring boards because it's more expensive, and more difficult to control & waste treat, so the short answer to your question is probably electroless nickel. But even that is being replaced by 'direct metalization' in many applications.

As you see, we added your inquiry to a thread about electroplating non-conductive materials. We have hundreds of threads on that topic here, and many books have been written about it, so it's not easily discharged in a single forum posting. Everything from animal skulls through flowers & leaves on up through plastic automotive grills have been metalized and plated. Your need sounds "industrial" rather than hobbyist or artistic, so I think you're on the right track with electroless nickel, but people really can't help you until we understand what you want to do -- for example "Standards & Guidelines for Electroplated Plastics" has a 30-page chapter just on those ASTM specs you request.

What is it that you want to electroplate? What material is it made from? What is it that you want to ultimately plate it with (gold, chrome, a PVD coating, etc.)? Why do you want to plate it (appearance, corrosion resistance, electrical conductivity, wear resistance)? Thanks!

Regards,

A. Hi again Salem. ASTM B733 is the spec for electroless nickel plating, and other standards organizations have other specs; please see thread 39060 for a general discussion of the standards. But that spec only covers the electroless nickel step itself, not the whole sequence for plating on plastic.

There are a few things you may or may not be aware of, but I'll mention them for the benefit of other readers --

1. There are many different metalization techniques; not just the electroless nickel, electroless copper, and direct metalization methods already mentioned. See our FAQ "Plating Organic Materials" for a quick introduction to some other approaches. Almost anything can be metalized for subsequent electroplating, but a principal issue is usually the need for extreme and flawless adhesion, and some methods can't deliver enough for difficult industrial needs.
2. The process for applying electroless nickel to plastic is somewhat involved. It's not one step, but many. Exact sequences and names vary, but typically etch, activate, accelerate, electroless nickel plate (with rinses between each step) would be the minimum. Thread 1020 presents typical process sequences.
3. ABS is a special plastic designed for maximum adhesion; the butadiene is dissolved in an etch, leaving millions of tiny little spherical pockets the Pd activator deposits into, and onto which the electroless nickel grows. You can metalize other plastics but you won't get equivalent adhesion because you won't have those spherical pockets.

Regards,

Dear Ted.

your kind and informative response to my question is highly appreciated.
thank you very much,