making new copper look aged green

[ransley]

How do you get new copper to look naturaly aged green and stable, Verdigris. I have used acids Hydrochloric, Hydroflouric, and find the Verdigris is a top layer and sometimes bluer or darker green than naturaly aged copper.

I have found Toilet bowl cleaner that has Hydrochloric acid is great on old black copper gutters that wont fully turn green, as its already buffered and gelled so it stays wet and doesnt drip on you as you brush it on, and safer to use.

I have fumed copper in a heated tub but the results are darker and more green than natural aging and the finish flakes off. I have heard to sand and or heat the copper with a propane torch and that even Pee is great, this I willl try next. There is a process to make copper green and stable but I dont know it. Revere copper does it. Im on the other side of the pond so excuse my terminology, this week will be back to 0f degree, a bit cold.

[Andy Dingley]

You find a copy of "The Colouring, Bronzing, and Patination of Metals" and then spend ages studying it.

Copper goes either brown(ish) or green(ish) with most reagents (so buy some nitrate-based stuff). Much depends on the copper alloy, the reagent (obviously) and the process (time / temperature / agitation) you use to apply it. Getting nice colours is one thing, getting consistent results, stable results or predictable results is quite another. Japanese work uses the same reagent repeatedly and varies the alloy instead. This is allegedly an easier route to reliable consistency (although some of their alloys are arsenical and quite toxic).

Avoid chlorides. That's not patina, it's corrosion - and it's very far from stable or robust.

For simple results, buy a commercial bottle of Green Goop or Brown Goop. You'll get better results than anything short of serious investment in materials and techniques.

[ransley]

Nitrate base, do you mean plant fertilizer. Green Goop, Brown Goop, what is in the products, I never heard of them in the US, I will try google on the goop.

[Nige Danton]

You might somthing of interest here:

've also tried fuming the copper in amonnia.

[Nige Danton]

Also maybe search rec.crafts.metalworking for more ideas and tips.

[Andy Dingley]

Ammonia fuming is great, but it tends to give a mild "antique" patina, rather than a deliberate verdigris. Works very well on brass. Didn't we discuss that recently? The trick is to keep the metal out of the liquid ammonia, otherwise it develops splotches. The usual method is a big Tupperware box, with ammonia in the bottom, then a layer of wood shavings, with the metal above.

[Andy Dingley]

No, I generally mean ferric nitrate, the base for a great many patination recipes. Also nitric acid.

You're unlikely to get far "trying out brews with plant fertiliser". In particular you'll find yourself with a weak mixture that acts very slowly. This is a bad thing. In particular, you might think it looks good but the stuff is so slow acting you don't realise it's still working - a week later it has turned to ugly crud. This is particularly a problem with chlorides. Washing and cleaning afterwards, maybe even deliberate neutralising, can be as important as the patination itself.

This looks like a decent online starting point

of course there's Ganoksin for serious metalsmithing. Green Goop, Brown Goop what is in the products,

No idea. Many chemicals used in metal finishing (especially plating) are obscure and difficult to find, then only used in small doses. It's too awkward to buy your own, so you're better buying a ready-mixed patination fluid. This still applies, even if you're an industrial chemist (unless you can sneak through a 40 gallon drum of something that you only need a teaspoon of).

Find your local finishing supplies people (Rustin or Liberon in the UK) and check their catalogues. It does work better if you buy the ready-mixed potions, then follow the recipes carefully.

[Mr Benn]

I have experience of this although unintentionally. I once kept a bottle of concentrated hydrochloric acid under the kitchen sink. Over time, the cap of the bottle degraded allowing hydrogen chloride gas to escape from the bottle (the acid is basically this gas dissolved in water). All the copper piping went green (copper chloride).

I suggest you get some concentrated hycrochloric acid (available from Robert Dyas - sold as drain cleaner) and leave the copper item in a small chamber with an open container of hydrochloric acid for a few days.

Warning: The gas is very harmful to your lungs and other moist membranes so make sure you do this somewhere safe.

[pete]

Got any cow-pats nearby?

[Nige Danton]

No... not me and I didn't see the thread.

[Appin]

The message from ransley contains these words:

Horse urine was the traditional material used in Eastern Canada where there were and are a lot of copper roofs in the Montréal - Ottawa area.

[ransley]

Thanks, Ganoskin has procedures listed I was not even aware of, the pre cleaning. I thought dirty was better. This is more an art form and experiment than anything.

[Andy Champ]

I understand that urine works quite well. I heard a tale once - possibly apocryphal - of a university piping the urinals from the gents onto a copper dome...

Andy

[S Viemeister]

An architect I used to know, claimed that the roofers were encouraged to pee on the copper roof...

[george [dicegeorge]]

How do you get the horse onto the roof? wait for xmas and reindeer? [g]

[Rod]

Easier than getting the horses to do so.

[geoff]

I dunno

once you got them on the roof, of course ...

[ransley]

Andy Warhol did some works in 1978 where he peed on paintings done in copper paint, they turned green.

[Thomas Prufer]

Here copper won't go green anymore, it stays brown. An architect explained to me it's the lack of sulphur compounds in the air. Used to be the sulphur in coal used for heating (and ISTR heating oil and diesel is now low-sulphur) caused the green -- along with acid rain...

Thomas Prufer

[S Viemeister]

That explains it - the architect who told me that, worked in Edinburgh in the 1960s - _lots_ of coal in the air.