Subject: How to make verdigris (green copper) finish???

From: [email-masked] (Ben)
Date: Sun, 4 Jun 1995 07:39:20 +1000

Does anyone know a method for obtaining a good verdigris finish on copper?

I understand it is formed by a reaction with acetic acid and I have had some 
success using vinegar.  I have been told there is a commercial product sold in 
art catalogs for this.  I would like to obtain a consistent finnish that can 
be preserved by clear lacquer.

Thanks,  Tom

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From: Tom Annear <[email-masked]>
Date: 5 Jun 1995 11:47:10 GMT

I am jeweller/sculptor and to get the surface patina you describe, I use 
a butane torch and a household spray bottle filled with copper nitrate 
solution [~10%].

The workpiece needs to be hot enough to sizzle when the solution hits it, 
and you should be careful not to lay the patina on too thickly to begin 
with. 

Also, you might find it helpful to scratch brush the surface from time to 
time with a stiff bristle brush to help set the surface, and make sure 
any loose stuff gets knocked off.

You can get a range of colours depending on the amount of heat you use. 

I generally finish with silicone based floor wax, but laquer is OK if you 
like the glossier surface.

A superb source on this and other patinas is

"The Colouring, Bronzing and Patination of Metals" by Michael Rowe

cheers

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From: [email-masked] (Cori Stewart)
Date: 5 Jun 1995 17:21:07 GMT

Ben ([email-masked]) wrote:
: Does anyone know a method for obtaining a good verdigris finish on copper?

: I understand it is formed by a reaction with acetic acid and I have had some 
: success using vinegar.  I have been told there is a commercial product sold in 
: art catalogs for this.  I would like to obtain a consistent finnish that can 
: be preserved by clear lacquer.

Pee on it! 

-T. Shawn Johnson
(using Cori's account)

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From: [email-masked] (PeterWRowe)
Date: 8 Jun 1995 01:45:04 -0400

Ben ([email-masked]) wrote:
: Does anyone know a method for obtaining a good verdigris finish on
copper?

: I understand it is formed by a reaction with acetic acid and I have had
some 
: success using vinegar.  I have been told there is a commercial product
sold in 
: art catalogs for this.  I would like to obtain a consistent finnish that
can 
: be preserved by clear lacquer.

Pee on it! 

-T. Shawn Johnson
(using Cori's account)
<<

Folks, just in case anyone passes this post off as just flippancy, think
again.  Urine, left on copper for a time, does indeed produce a nice if
irreverent finish.  And it is a traditional ingredient in a number of
historically used patina, especially some of the oriental finishes. 
Rokusho mixes, in particular come to mind...

And I had a cat once, who, with the bad habit of spraying anywhere he
could, managed to get a rather nice bronze bowl I'd raised in college.  It
was easy to see where He'd gone, 'cause where the pee had dried on the
copper, it had turned a beautiful, and non-odorous (just in case you
wondered) blue green...

One account suggests, perhaps tongue in cheek, that urine produced as a
result of the copious consumption of beer or ale produces a better
finish...

Haven't tested that one myself, but some of you may wish to...

Cheers.
Peter Rowe

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From: Tom Annear <[email-masked]>
Date: 5 Jun 1995 11:47:10 GMT

cheers

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From: [email-masked] (Cori Stewart)
Date: 5 Jun 1995 17:21:07 GMT

Pee on it! 

-T. Shawn Johnson
(using Cori's account)