Want gold colored finishes without use of gold

A. Hi There,

It's true that you can get a yellowish colour for a top coat which is called yellow bronze - alloy of Copper 85 % and Tin 15 % but the finish may not be as similar as gold finish and also the tarnishing tendancy is very high; it's major application is for nickel free process.
The best works out for you is electrophoretic gold colour process which is very popular these days ... with a good gold and many more colours, and durability ... cha cha cha

A. The closest and cheapest alloy which looks like gold is brass (Copper-zinc).
You can find some good and free formulations in the Metal Finishing directory book.
If you have any difficulties to find the directory, I can send you one (give me an address in Europe or USA as there is no way I can send it directly to you ... but with time, I am sure we will be able to send books to each other).

Best regards

A. Try either brass plating, lacquers, or titanium nitride by vacuum deposition.

? Hi Shafeek Saati

Can you tell me what is the product made of (Substrate) which you want to make look like gold.
In case you can make it out of aluminum extrusion, you could brighten the same and have it dyed in golden color. This would make it look exactly like Gold or Brass.
The method is fairly cheap and inexpensive. What is important though is the volume of product you must process and a good understanding of aluminum brightening, anodizing and coloring.
Regards,

A. Hi Ateeq.

Presumably, Dr. Kushner means that the color will come out best if the copper and tin chemicals are adjusted so that 88-91% of the metal in solution is copper and 9-12% of the metal in solution is tin. But we gave you the link to the article; please read that short article yourself rather than relying on my interpretation of it. Good luck.

Regards,

A. Hi Anthony. There are more than a dozen commonly plated metals, hundreds of alloys, and thousands of combinations of plating. But zinc is the most common plating for steel and it often receives a post treatment of yellow ("gold") colored chromate -- so I suspect that's what you are thinking of. No one would confuse it for gold, but on cheap stuff like the innards of door latch hardware people sometimes think it's brass.

Regards,

A. Hi again Anthony. Chromating is a simple dipping process directly after rinsing the zinc plating. When using the safer trivalent chromates (free of hexavalent chromium), it is usually necessary to follow the chromating step with a dip in a proprietary sealer or post-dip for good corrosion resistance. Production shops will sometimes do a dip in dilute nitric acid between the zinc plating and the chromating, but it's probably not necessary for a hobbyist.

If you were asking whether it's dangerous for experienced platers who've had hands-on OJT training & annual haz-mat training, and are wearing proper protective equipment, no it's not. But if you mean are there any possible dangers for an inexperienced hobbyist, his children, and his pets in trying to do an industrial process on his kitchen table, yes, certainly.

Although the most straightforward way to approach the project is to send the parts to a plating shop, we also have dozens of threads on this site about what hobbyists can do, how they can substitute more laborious operations for more risky chemical ones (e.g., scrubbing with pumice in lieu of caustic cleaning), and what they still should never attempt (e.g., cyanide-based electroplating, hydrofluoric acid pre-treatments). A very determined hobbyist who is careful can surely successfully zinc plate steel parts and buy gold-colored trivalent chromate conversion chemistry and apply it without hurting himself. You can prove to yourself that you are a determined hobbyist by going through the Metal Finishing Guidebook cover to cover -- not necessarily reading each word, but at least glancing at every page to reduce the chances of broad areas of gross misunderstanding :-)

Regards,

A. Hi Umang. We appended your inquiry to one of many threads about finishes that "look like gold". Titanium nitride looks very much like gold but is vacuum-deposited not electroplated, and probably not suited to low volume; brass plating can look a fair bit like gold to some people but tarnishes; zinc plating with iridescent gold colored chromate looks vaguely gold-ish but wouldn't fool one person in a hundred.

If you want real help on this, it isn't going to be sufficient to be vague; rather, you must write several paragraphs explaining exactly what the parts are, what environment they will experience, why you want them to look like gold, and how many you need so we know whether very high capital costs like for Titanium Nitride deposition are feasible, what your skills are, etc. Thanks, and good luck!

Regards,

A. Hi Claude,

As long as the SS alloy is not 316, gold colors can be achieved by anodizing. It cannot be done in basket, but still the process is pretty economical. Please see the attached photo.

A. Hi Narendra
Surely there are gold-tone paints that can be applied in one step. Electroplating on ABS requires at least a dozen steps.
Luck & Regards,


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

A. Hi Byron. A thin layer of brass plating deposited onto a shiny surface like polished stainless steel or bright nickel plating can be bright without polishing. A very heavy layer, or any layer deposited onto a non-shiny surface will not be shiny.

If applicable, brazing will be a better joining method than welding -- it's much easier to grind smooth and bright nickel plate. It is unlikely that you will be able to maintain brightness without brass lacquer or a clear coat, however, because brass tarnishes readily.
Luck & Regards,


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

A. Hello Awadhesh!

You can put a drop of 5% hydrochloric acid on the part you want to assess. If the drop dissolves the coating, it is zinc. If not, it may be gold.

XRF must give you accurate data about the coating. It should give you thickness and composition of either zinc, gold or any other metallic coating.

Hope it helps! Best of lucks!

Daniel

A. Hi cousin Viraj. There are many ways to get a generally golden color without using gold: from vacuum metalizing with aluminum followed by a gold tinted lacquer, to PVD coating with titanium nitride, to brass plating in a barrel, to chrome-look paint plus tinted lacquer, to CED coating and post-dyeing, to specialty gold-tone paint. Further, when you say it's an "imitation product", that by itself doesn't really rule out gold plating, as costume jewelry and imitation jewelry is usually gold plating on a cheaper substrate.

So it's hard to suggest anything until you give us a requirement & parameter or two.

Luck & Regards,

A. Hi. Those ball bearings can be brass plated in a tone which looks somewhat like gold, but they must then be lacquered because brass tarnishes pretty quickly. What is the intended use of these brass-plated-&-lacquered ball bearings -- jewelry of some sort? Hopefully, there will be no real gold on the jewelry because a perfect match of brass plating to gold is a tall order.

You can inquire of local plating shops if they can offer you barrel brass plating, and get some samples to see if the color is close enough for your purposes. But as already mentioned, there are many different possible approaches to getting a gold-look finish, depending on your application, situation, and desires -- which we still know little about two years later :-)

And remember that real gold is NOT expensive if you can get away with a flash of gold a few millionths of an inch thick followed by a clearcoat.

Luck & Regards,

A. Hi again Viraj. The least expensive way to get a short-lived golden color on this is probably vacuum metallizing. A very thin layer of aluminum is deposited in a vacuum chamber, then a tinted, protective topcoat is applied. In very high volume the coating is very cheap -- it's even used on shiny mylar balloons.

The downside is that the equipment is very expensive and unsuitable to a small shop. With some skill, and at higher unit cost but much lower capital cost, "chrome-look paint" with a tinted topcoat can be applied with similar results. Please search the site for 'chrome-look paint' or 'spray chrome'.

Luck & Regards,

A. Hi again. If you prefer to do electroplating rather than vacuum metalizing, that's fine. This can be done in a series of individual oblique barrel plating stations, or in an automatic oblique barrel plating machine as illustrated (courtesy of the Canning Handbook).

The Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon] as well as the Canning Handbook ⇨
have good chapters on the topic, but your proposed production volume doesn't approach justifying an automatic oblique barrel plating machine.

Today it's more common to use horizontal plating barrels anyway, either transferred from tank to tank with a manual hoist on an overhead rail, or automated with a programmed hoist (or even manually if very small barrels are used). See our library article on barrel plating. I imagine that you will want plating barrels much smaller than those illustrated (because they could easily produce your month's production in a single 8-hour shift).

I believe that the talk you've heard about "silver color" may have to do with the fact that brass plating (as well as gold plating) don't have much shine if applied directly to steel. The shine is usually produced by an underlayer of bright nickel or white bronze plating.

I suspect that you want a small and simple manual barrel plating line including the steps electroclean, acid activate, white bronze plate, and brass plate, with rinsing between each. If I were you I'd consider finding a finishing consultant. I no longer do consulting work, but something I learned from doing it for 25 years or so is that the early decisions are the most important ones, but clients usually don't retain a finishing consultant until near the end ... after the freedom to optimize the plan has become severely limited.

Luck & Regards,

A. Hi Jason. Unfortunately, applying aluminum over the steel is not something a hobbyist is likely to be able to do nor have a plating shop do at an affordable price.

I think the best approach for a decorative sword will be "chrome-look paint" with a translucent gold-tone top coat. These "paints" are not the hardware store gold-tone paints you might envision. Rather, they are a 3-coat (or more) system where the base is a tailored primer coat, the middle layer is done with silver nitrate plus a reducing agent to leave a shiny chrome-like look (essentially the 'mirror silvering' process), and then a topcoat which is often clear but can be tinted. You can contact Gold Touch [a finishing.com supporting advertiser] and G.J. Nikolas [a finishing.com supporting advertiser] about it, or google for "chrome-look paint" or "spray chrome".

Luck & Regards,

Gold leaf

A. Try gold leaf or imitation gold leaf (cheaper). Or try ferrocyanide based gold plating bath (if your sword is ordinary steel you can gold plate it with ferrocyanide based bath directly). Potassium ferrocyanide [on eBay or Amazon] is non-toxic cyanide compound. Hope it helps and good luck!

Hi again. I thank Goran because the possibility of gold-leafing slipped my mind and I think that idea is better than mine was :-)

Luck & Regards,


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