This will help to achieve an even patina so skip this step if you want something more patchy.
How to oxidise copper sheet.
The copper should not be touching the ammonia liquid but should be raised above it.
To oxidize copper begin by scrubbing the copper with an abrasive pad and water.
Using the fumes of household ammonia to oxidize metal is really quite easy and is an inexpensive way to oxidize copper and brass.
The sealed container will trap ammonia vapors that will then make contact with the copper.
Apply the los carefully and watch the reaction to the copper.
Basic products like vinegar and salt can have the same effect.
As a simple project to test out the process use vinegar and salt to oxidize pennies.
Spray the patina on the clean oil free copper and let set for 2 or 3 hours to dry then repeat 3 or so more times until you get what you want.
Mix the ingredients into a spray bottle for easy application and shake it up to mix the ingredients thoroughly.
Some authorities claim that heating the copper to a working temperature gives best results.
Place pennies in the bowl for several minutes.
Prep your copper piece by cleaning it and then spraying it with window cleaner.
While in the bowl the dull pennies will start to brighten up as their copper oxide layer is removed.
Spray the copper with a solution of salt water and then place the copper in a container that contains non detergent ammonia.
To quickly oxidize your copper the best mixture involves one cup 24 liter of plain white vinegar 3 4 cup 18 liter of household ammonia and 1 4 cup 19 liter of table salt.
Be careful not to burn yourself.
You can also soak sawdust with the patina and pack it around the copper piece and seal it in a plastic bag for a day or 3.
Most harsh substances are capable of oxidizing copper but you don t need to buy special acids just for that.
Then clean the copper with soap and water and pat it dry with a soft cloth.
Here s one way to force oxidize copper.
To see the birdhouses i built check out this video.
All you need is enough amount of these products to submerge your copper item for a certain period.
Try the solution on a small bit of copper before proceeding.
This can be done with a small handheld butane torch like those used for plumbing.
I got a sal ammoniac block from ace at the time but i don t see it now at their website.