Copper oxidizes very easily.  That is why sterling silver, which contains 7.5% copper, tarnishes so easily.  I generally prefer to use Gun Blue to patinate copper - it turns dark in seconds. No smell either. Household ammonia is much slower and very pungent.  But as you will see with this tutorial on how to use ammonia for blue patination of copper, the humble cleaning solution is great for color formation.  The tutorial is by Creatinglinus over on Instructables.

There are some really good tips including how to make a fume chamber.  I also like the fact the ammonia solution is poured onto a paper towel.  The ammonia gas will be released to fill the container.  As not much ammonia solution is used it is easy to dispose of after use.  Just put the open container outdoors, out of reach of animals and humans, to make sure all the gas dissipates.  Don't breathe in this stuff!

It is important to really clean the copper well beforehand. Otherwise, the grease and dirt will hinder the reaction with the salt and ammonia.

Note that you must seal the final piece as instructed.

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Original Post by THE BEADING GEM
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