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Outdoor patina for large mild steel sculpture

I am blacksmith designing a large scale forged mild steel sculpture to be sited outdoors. I am discovering that powdercoating and paint are not ideal solutions for my piece. I was thinking that there may be an interesting patina that I might apply to a galvanized surface. This would add visual interest to the highly textured surface of the metal as galvanizing looks somewhat flat. I also hoped that a patined surface would "weather" and diminish the possibility of a botched reapplication of paint over time.

Lauren Osmolski
artist blacksmith - Seattle, WA USA
August 25, 2009

If galvanized=zinc plated you can use any zinc colouring solution(download/free!/ old book by A.Hiorns/Metal Colouring/-www.archive.org).Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
August 28, 2009

Thanks. I have heard from another finisher that the zinc patinas don't hold up well outdoors for long.)(Don't know what he put over the sample that he tried) However, I will look into this. This is for a piece of public art and will have to be cared for over time by those less interested than myself, I have to try to be reasonably sure that the city will get a decent amount of time out of something/anything that won't last forever.

Lauren Osmolski
- Seattle, WA USA
August 31, 2009

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Dear Lauren
TRy next webpage: http://206.180.235.133/jaic/articles/jaic42-01-003_appx.html
-very good article on conservation of zinc public monuments.
Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
September 2, 2009

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Here in the UK there's a pretreatment for painting galvanized steel called "T Wash".
This is a phosphoric acid with Cu in it I think.
But an alternative use is adding a blackening patina to galvanizing.
We had a customer do this to a sculpture some years back and it still looks great. Its a sort of greeny blackening, but its irregular, not a uniform colour. In some situations looks very nice.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK

September 2, 2009