Spray chroming with silver nitrate

A. Mr. Sameer Haque, when you first published your question about the issues you had with high surface tension you were having with your PU base for the Spray On Silver process, I believed that you had figured out the process and the chemicals, but it seems that you are starting from scratch.

Let me tell you my story in hopes it may help you in the long run.
When I first saw a video of "Spray On Chrome" done by one of the big players in the industry, I was beside myself, amazed, it all looked like magic and I made up my mind that I wanted to do this as a business. Then I found out just how expensive this can be, but I was not discouraged, I thought that maybe if I could get myself the basic chemicals I could make it big, be the first Nicaraguan in this business.
After learning that spray on chrome was really just silver spraying, I dedicated countless hours learning just the basics (I had not found this very helpful forum); I purchased expensive Silver Nitrate, Sodium Hydroxide, Ammonium Hydroxide and inverted sugar (table sugar and citric acid ⇦this on eBay or Amazon [affil links] ), the basics of Tollens' reagent; it all worked very well in test tubes made out of glass. I said to myself that I was ready for testing on properly prepared plastic pieces (plastic spoons), but nothing --nothing-- was working; the chemicals were not staying on the spoons, and I kept wasting precious time and money. Things were not looking good; I was desperate and only myself to blame because of the countless variables, but I was too dumb to know when to quit.

It took me about 6 months to save enough money to purchase and bring silver mirroring chemicals (spray on chrome chemicals were out of my league), surely this time I would make it ... Big and Success was a matter of time. I got the chemicals, I had the plastic spoons ready, but things didn't go as planned; I was able to Silver the spoons, but I had issues with the basecoat and clear coat, they were interacting with each other, ruining the test pieces. I was very disappointed, but progress was made nonetheless.

I gathered up strength and money again for one last try, the third one had to be the charm right?, I learned that automotive clear coat was the best (albeit it introduced higher surface tension as opposed to single component enamels that were more glass-like in nature). So I purchased a wetting agent, automotive base/clear coat and chemicals from trusted Mirroring company (they didn't know anything about spray on chrome yet so no hope for tech support). Wow! I was very impressed with the results, beautiful first surface mirror on properly prepared plastic spoons (simulating a future working piece), but I was not out of the woods yet; as impressive as the silver mirror was, my next and last obstacle to success was the top coat -- it turned all of my working pieces to yellow tone; I was in trouble: unless my future clients wanted colored chrome (which I did plenty in blue, gold, red), I could not make the pieces look like real chrome. I tried ever single cleat coat available and none worked, I was really disappointed. After a few years of research, a lot of money invested, time wasted, sweat and tears all for naught, but I was too close to success to give up, and again too dumb to quit.

So yet again I gathered up strength and resources to bring the needed chemicals and tools, so after years of self research, a lot of money spent, sweat & tears I was able to accomplish what I set out to do. But success is a relative term, and Business Success and a Successful Spray On Chrome set up are not the same thing ... I am still struggling with making beautiful art that is well paid and costumers that want that beautiful art for less & less money.

So here is my advise, I have a friend in the business in India; here is my email address (nicamarvin2005@yahoo.com). Contact me and I will send you his contact information; purchase the required chemicals and tech support from him and save yourself the grief you are surely going to experience.

Best of luck cousin Sameer, and anyone is welcome to answer, but I'd suspect that we're pretty much done here :-)

Regards,

A. The fact that you have made it to the Protective Top Coat means that you have done some progress, which is good, but you are not out of the woods yet.

Okay, so why does the spray silvering turn yellow after clear coating it?
Unlike metals such as aluminum or chrome, silver has an optical property called thin film interference that makes it appear pale gold or yellow when coated with any thin transparent film even distilled water. To counter-act this phenomenon, it is necessary to tint the first layer you apply to the silver with transparent Violet . While blue is the color opposite of yellow in terms of light, many blue colored tints tend to look green when they are very dilute. The red tones in a Violet tint counteract the greenish look of the blue to give a pure chrome like blue, not every tint will work and professionals use automotive UV resistant Violet tints or what are called candy concentrate.

Here are a few videos I made about the subject.

(Ed. update Oct. 2024: Apologies but these videos are no longer available)

I posted an answer to this question twice days ago, I was waiting for at least one to be posted, but it seems it got buried in the sea of questions that most likely spam this forum, it may get tiresome having to post the same answer multiple times, but I am sure I am not the only one so I will keep doing this.

To the question:

Unlike metals such as aluminum or chrome, silver has an optical property called "thin film interference" that makes it appear pale gold or yellow when coated with any thin transparent film even distilled water. To counter-act this phenomenon, it is necessary to tint the first layer of the top coat that you apply to the silver with a translucent violet tint. While blue is the color opposite of yellow in terms of light, many UV resistant blue tints tend to look green when they are very dilute. The red tones in a Violet tint counteract the greenish look of the blue to give a chrome-like appearance.

Hi Marvin, thanks for your generous & insightful response! Sorry for the delay on your posting; but since it's the second time on this thread that you've mentioned the delays, it's a good time to clarify ... Yes, we receive more than a thousand spams per day, and we occasionally get swamped, especially when vacation week comes right before the Easter holidays. But as long as the e-mail was sent using the forms, they never get filtered into a spam box; and if they are answers from a regular responder like yourself, they ALL do eventually get posted. We all must make choices, and my choice was to try to build a quality reference site via manual posting, rather than a hostile, spammy, ad hominem, automatic posting site ... even though it means people don't always get immediate answers. The single biggest time sink for me is that readers do not patiently use the search engine, so they post repetitive questions that were already answered, and they post on way off-topic threads when there were threads that perfectly matched their question. If every thread wanders into everything, readers can't find anything, and the threads drop out of google search ... so I just do the best I can, doing the search myself, rearranging & renumbering, separating & combining, but it does mean delays; so, yes, new questions unfortunately do frequently get buried, but 90 percent were repetitive or abstract, or posted against an unrelated thread anyway:-) Regards, Ted Mooney, P.E. RET Striving to live Aloha finishing.com - Pine Beach, New Jersey April 2017

Flame Treatment

A. I would like to add that I finally decided to use the Flame Treatment process instead of the wetting agent, I have tested it on small pieces and not only makes the highly hydrophobic surface of the articles very wettable and hydrophilic, it also provides outstanding adhesion of the Silver layer.

My concern was using a flame on a highly combustible article(plastic parts covered with petroleum base coating), but when properly applied the process is rather safe and the process is well documented and understood.

I am building a set up identical to this one on this video, Propane Torch kit for about $40 and a propane tank for larger parts.

A. Hi Waleed. Much of this thread has been on that subject. Please try your best to phrase ongoing questions in terms of what has been said because simply starting over is the kiss of death to a thread :-)

Regards,

Hi Saravanan. The seller CAN reveal the ingredients for each of them, but I doubt that they will. You may be able to find some of the ingredients from the seller's SDS and technical data sheets though.

If you wish to copy someone's formulation rather than buying the product, or licensing it, or developing your own, that's your choice ... and reverse engineering is widely considered legitimate when it's done properly. But we can only post references to published information: books, technical papers, patents, etc., on such formulations because this is a no-registration-required website, many of the readers are strangers to us, and we have no way of distinguishing information that was legitimately obtained vs. what wasn't. Sorry but we can't participate in what could easily deteriorate into crowd sourcing of industrial espionage. Good luck!

Regards,

A. I would like to point out that when I first started with the so called Spray On Chrome process about 12 years ago, I had to adapt many old techniques and already proven processes to create my own DIY kit; I had to because any kits from proven manufacturers are worth many thousands of dollars and while the system I built was very sound, the weak link on it is the home brew chemicals and the Basecoat/Clear Coat.

I built my system around the LP Vinyl Record Silvering process, this process coats previously lacquered records with Silver using a two part chemicals mixed with a two part spraying gun.

For more info on the process you may want to check thread 45646 and thread 44444.

That will get you started with the Silvering process.
Let's say you master the Silvering process with your own home brew system (I never did), then the next step is to test Base Coat/Clear Coat system that will work with said system, I tried everything from lacquer to 2k Automotive coatings, I found the 2k system to be superior to non-catalyzed coatings, they give you super smooth glass like surface, but they are very hydrophobic, so stronger wetting agents are required (lacquer is very wettable in comparison).

In the end my home-brew chemicals did not produce reliable results always so I decided to purchase Mirror Silvering chemicals (much less expensive than spray on chrome chemicals) but my top coat was always turning the silvered process a yellowish tint, which is really not bad if you are going to make colored chrome parts (like blue, green, yellow, red) so I had to tint my clear coat with a Violet translucent pigment, while I wrote down the exact amount of tint per clear coat sometimes the ratio was off due to the manufacturer of the tint, now you can imagine how hard was to start over from that when the color did not match.

The entire Spray On Chrome process is unbelievably complex -- making your own silvering formula is just the tip of the iceberg -- you need to take into consideration coating compatibility, spray equipment settings (booth, compression, type of spray guns(cheap guns will give you cheap results), dirty compressed air will ruin your work).

A. It's very simple, Marvin -- why are you trying to make it sound complicated?
(Joking of course!)

Regards,

A. Hi Lung. Marvin Sevilla (whose post immediately proceeds yours now) is a highly accomplished chrome spray artist, and even he has struggled without success for 12 years trying to do without proprietary chemicals because of the difficulty of getting them in Nicaragua. He talks about the wetting agent on March 12, 2017 on this thread among other places.

Please give us your situation: are you using a proprietary system? If so, what do they say about the wetting issue? Or are you trying to develop a spray chrome system all by yourself? Thanks.

Luck & Regards,

A. Hi Hakky. Marvin Sevilla said he's used it and it worked just as well; Geoff Smith says any chloride will reduce silver. But please put your question into context by describing yourself & your situation. Thanks!

Luck & Regards,

A. Hi Vippin. The general chemistry and the general procedures of that step is already explained several times on this thread. Please try to ask a specific question, and post the details of your own situation because the silver reduction step is probably the easiest step in the process of satisfactorily spraying "chrome-like paint". Proprietaries may not be essential if you're an excellent chemist and have time for experimentation, but they would make things much simpler for you :-)

Luck & Regards,

A. Hi Jitendra. You can google for "SDS Hydrochrome®" to get the Safety Data Sheets for the silver nitrate and the reducer; these will give you the basics of the ingredients.

Good luck with it, you are certainly free to experiment yourself, but as Marvin Sevilla advises in detail on this page, even after years of intense development efforts his results fell short of what can be purchased right off the shelf. He has, however, been extremely generous in disclosing the details of his efforts, so take advantage of what you can learn from his postings, then have at it if you wish :-)

Luck & Regards,

A. Hi Pete. "The grass is always greener ..." Sorry, but I thoroughly doubt your 20,000% markup calculation :-)

All the information you need to get started in trying to make a viable spray chrome process is already on this page; the central "mirroring" step itself using silver nitrate and ammonia ⇦this on eBay or Amazon [affil links] or other reducer is pushing 200 years old.

The issue is, as Marvin tells us, that it's complicated to get good robust results. The base coat has to be right from many different perspectives: smooth enough but offering enough adhesion both to the base steel and subsequent layers, good at self-leveling, non-reactive with the subsequent layers, easy to activate, etc). The wetting step has to be done right. Then the activation step. The silvering process itself is, as mentioned, very old and established and recipes are on this page (as well as some warnings about ammoniated silver if you're tempted to use that) ... but Marvin warns that without that proper "activation" step before it, it just doesn't work like in the movies. Then you need a clear coat that is non-yellowing and doesn't hide the shine, but is tough enough to keep the silver from wearing off, and which doesn't affect the silver.

The starting info is all here, just as you can find the starting info for making the finest french pastries on line. But the chefs who bake them have little to fear from you or me, because it takes technique and broad knowledge from years of experience. Nor apparently do the sellers of proprietary chrome-like paint have much to fear from even the most dedicated individuals like Marvin.

Best of luck! One day it may be easier, but for right now it is quite difficult to develop your own robust chrome-look paint system. We would be very pleased to post whatever you learn from your experiments.

Regards,