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Zinc Patina Question!


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Hello everybody,

I'm really stumped.

I purchased a cupric sulfate solution from rotometals. I tried applying it to an existing zinc table (after exposing shiny zinc using 00 steel wool)

I left it on for about 1 minute with no dilution, however, the color did not change at all.

How come the metal isn't changing color? Does the patina need to somehow soak longer? Is it a different metal underneath the zinc that I'm hitting after using the steelwool?

All help is appreciated!

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Welcome aboard ZP, glad to have you. If you put your general location in the header you might be surprised how many members live within visiting distance.

What have you read about copper plating zinc? You might see if the library has a copy of "The Patination and Coloring of Metals," by Opi Untract. YOu might have to ask the local library to ILL it for you.

First off. Oh YEAH it needs more than 1 minute!:rolleyes: How about leaving it submerged until you have the level of plating you want?

Maybe try electro plating? We were electro plating copper onto nails with directions from "Boy's Life" when I was really young, maybe 8?

All you need to do is a little basic research, plating zinc with copper is really easy once you  know how.

Frosty The Lucky.

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Welcome aboard from 7500' in SE Wyoming.  Glad to have you.

It would be a help if you put your general location in your profile.  This is a world wide forum and we don't know if you are in Kansas, Siri Lanka, or Argentina.

Regarding your query:  Are you sure that your table is zinc and not something else with a zinc or galvanized plating on it.  You need to know what kind of a chemical reaction you are expecting, oxidation, reduction, or something else.  There is also the possibility that you need to perform some sort of electro plating where something is deposited from the solution or another piece of metal because of an electric current passed through the objects and an electrolyte liquid.

You can probably tell if your table is zinc by how hard it is.  Since is softer than most other metals.  Can you scratch it with the tip of a knife?  Also, if it is cast it may be some sort of pot/white/zinc alloy metal which may react chemically differently than pure zinc.

"Byt hammer and hand all arts do stand."

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  • 3 weeks later...

I'm late to the party, but copper sulfate usually is used to darken or blacken zinc - you see it done to artificially age zinc countertops and whatnot. If it's had time to oxidize, you hit it with a very light sanding using 00 steel wool (extremely gentle if it's only zinc plated or you'll scratch through it), then clean with a solvent such as acetone or denatured alcohol.

What you do next depends on the texture you want. Smooth black, spray or sponge it on, let it set a little, then wipe the excess off. If you get too much it'll look mottled. Cool if you mean too, less cool if you didn't. If you want it less of a smooth black, let it dry on, Even less smooth, add something like kosher salt or a little sand over the top. Make sure you also follow manufacturing instructions for dilution of the copper sulfate - a lot of the time it comes concentrated.

Anyway, clean it after it dries with a little water - some people use alcohol or acetone - then repeat until it gets as dark as you want. It only darkens a little at a time, in thin layers, so you'll need anywhere from 6-10 coats to get it where you want and have it be sort of permanent. You'll also want to coat it with something like lacquer or polyurethane to protect it, especially if it's going to be used around things you intend to touch routinely or food prep.

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Yeah, I know, but I figured somebody could probably use the info, even if only down the road aways. And besides, the horse could always sing and he might come back. Probably should have also added that gloves are a must and don't get any in your mouth or touch your eyes.

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I'm always down for a party even if I am late to it.

By the sounds of it I agree with Nobody Special about it only changing the zinc finish.

Due to the series of metal activity/reactivity chart zinc is one of the most reactive metals. Adding copper/cupric sulfate in theory will cause the zinc to go into solution/dissolve causing darkening.

Not sure of strength/time but if you leave even pure zinc in this displacement reaction long enough all your zinc will dissolve into solution/disappear.

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