Blue/green/verdigris patinas for zinc Q&A

A. Hi Man...

Goran Budija suggested 60 grams of nickel sulphate plus 60 grams of ammonium chloride per liter of water.

Rick Varnum says a spray bottle of blackening solution made for steel will work fine on zinc and, for countertops, should be followed by butcher's wax.

When asked for a formula that did not use ammonia, Goran then suggested 300 gram of copper nitrate per litre of water.

Luck & Regards,

A. Try my download free booklet on metals coloring and plating (https://www.finishing.com/library/budija/budija.pdf) ,there you can find small chapter about zinc coloring. Copper nitrate based solution can be used only on copper plated zinc objects (or any other copper coloring solution). Hope it helps and good luck!

A. James, verdigris green patina occurs on copper roofs, not on zinc ones, because the green color is a copper salt. Zinc roofs never turn verdigris color. Sorry.

For interior, lighter exposure, you can probably apply a copper-based patina solution, but on an actual roof the color would never hold up.

Black for zinc:

Cu(NO₃)₂......6,25 gm
NH₄Cl.........6,25 gm
CuCl₂.........6,25 gm
HCl..........6,25 ml
H₂O...........1 lit.

Bronze brown for zinc:

iron sulphate......50 gm
copper sulphate....50 gm
H₂O..........1 lit.

Blue for zinc:

nickel sulphate.......60 gm
ammonium chloride......60 gm
H₂O............1 lit.

Lustre colors for zinc:

NaOH........83 gm
copper tartrate..62 gm
H₂O........ 1 lit.

At 10 °C temp., 2 min. violet, 3 min. blue, 4-5 min. green, 6-7 min. yellow, 8-9 min.very dark red, without lacquering or waxing!

 Thank you, Goran Budija, for those recipes. I am anxious to try them.

  Hi, Ken. Goran is a metals conservator and seems to always have the answers I don't expect! Thanks as usual, Goran.

Regards,

A. I am maybe a bit confused, Kathryn. It's possible to get blue (verdigris?) patinas on copper, brass, and bronze because copper salts are blue-green, but zinc salts are not. You can probably wipe on a copper-based patina solution with enough effort if that's the look you seek ... but only practice makes perfect.

A. The term "bluing" is a generic term used in metal finishing of "steel" parts - most common in the firearms industry. The "blue" actually comes from the light reflection of an oil that is applied to protect the black oxide-type finish. That said, you may want to try a tinted lacquer to achieve the proper color, because an oxidizing process to color your zinc sheet will require immersion to achieve color uniformity. Also, a lacquer will help preserve the color and resist further natural oxidation. I would apologize to the metalworker, and then find an acceptable color/finish and tell your customer that they now have a one-of-a-kind ceiling.

A. You can put a antique Patina finish easily on your Zinc ceiling using the right chemicals in a spray bottle. I purchased an acid made for bluing steel that works great on Zinc.
We make Zinc counter tops all the time and I antique them then add a butchers wax finish.

A. Now I'm more confused than before :-)

I assumed, maybe wrongly, that when Kathryn said 'blue patina for sheet metal' she was looking for the mottled verdigris blue we may see on old roofs and gutters.
Dan seems to think she wants a black oxide finish (gun bluing), which on a highly polished surface looks a very dark jewel blue.
Rick is apparently very experienced, and can achieve a successful patina with a spray bottle, but describes it as 'antique Patina finish', which I assume is paler and less saturated than what I envisioned or Dan envisioned.
Can we get a better idea what Kathryn means by 'blue'?   :-)

Luck & Regards,

A. Hello, Jean. While new people read the threads every day and may be able to help you, Rick's reply is from 5 years ago, and it's unlikely that he visits this thread often if at all :-)

Jax Patina [affil links] may not be exactly what Rick uses, but should get you a blue-green patina. If, again, that's the look you're hunting for. Good luck.

Regards,

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Ed. note: Hi Alonso. What is this "brown O ring"? What kind of sheet metal is it made of? Can you send a photo to mooney@finishing.com for posting here?

A. Hi Justin. Verdigris patinas are possible (and can even occur naturally) on copper, brass, and bronze because copper salts are that color. But to get verdigris color on solder and zinc, you need to put copper on them; the easiest way is with a commercial patina solution.

You can probably check the MSDS to make sure they don't have ammonia.

Luck & Regards,

A. You can use copper nitrate ⇦this on eBay or Amazon [affil links] based patina: 300 gms copper nitrate/1 lit water only for grease and oxide free surfaces!

Good luck!

A. Have you thought about faking it, with a thin layer of acrylic paint? I suppose you make lamp shades, so they would never be submersed in water?

A. You can try next website (download free): http://www.thelitterbox.org/librum/i-sacof/433.gif !

black for zinc:
200 gm iron chloride
1 lit water

Good luck!

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Ed. note: Goran's link is broken, and we could not easily find the new location (if any) of the particular article in question ... but librum (www.librum.us) is without doubt one of the most fascinating sites you'll find!

Hi, Ben. Please see such books as Color on Metal ⇦[this on on Amazonaffil links], "The Colouring, Bronzing & Patination of Metals" [on eBay, Amazon, AbeBooks affil links] , Contemporary Patination.

and Patinas for Silicon Bronze [on on Amazonaffil links].

Yes, you can buy patina kits and chemicals such as green patina [affil links] .

It may also be possible to get some simple patinas on certain metals by repeated application of household chemicals like vinegar ⇦in bulk on eBay or Amazon [affil links] and salt; that subject has been covered many times on these pages, so use the search engine or see the FAQ on that subject. Good luck.

Regards,

Hi Ross. I've personally not heard of a good patina for galvanized steel, but there's always a first time.

A. If your objects are zinc plated You can use any solution for colouring zinc. If you want verdigris type colour You must first copper plate your objects, then you can colour them like copper. And one formula for blue/violet blue patina for zinc:
60 gm nickel sulphate
60 gm ammonium chloride
1 lit water

Immerse object in solution,. If you use ammonium nickel sulphate You can obtain violet blue colour.
Hope it helps!