There are differences between cold and hot patination. Claire
Sanford who wrote a chapter on patination in Tim McCreight's book,
"Metal Technics", was my instructor at Mass Art. The ammonia style is
a "cold" technique, where you insert your copper or bronze piece in a
bag, lightly mist it with water and sprinkle a light coating of salt.
Place the piece in a bag with a dish of ammonia and let the piece
"cook" for 24 - 48 hours.
The other process that Noel described is commonly called a "sawdust"
patina. This can be done with other items than sawdust, such as
macaroni of all things. Different woods have different oils and
acids, such as oak, cedar, pine, maple, etc. Each one will react
differently to the patina mixture. You can get some pretty amazing
colors with the ammonia and certain sulfates, like copper sulfate.
Don't saturate the wood chips, just make sure they are moist and make
very sure that your wood chips are not from pressurized wood or some
wood that has critter reducing chemicals. When you open the bag, be
sure you are outside or wearing a respirator or both. Man, it is
The second process is using heat. By using a torch, you gently heat
the piece using a light spray with either cupric nitrate, ferric
nitrate or cupric sulfate and alternate between heating and spraying.
This builds up a coating of patina onto the copper. Too much heat and
you will burn the patina. Too little heat and the patina won't stick.
In either case, the copper needs to be completely grease free.
For cold patination I like Butcher's wax. It is intended for cold
work. Apply a light coating, let it dry completely and buff with a
soft cloth. I like to do this about three times.
Renaissance Wax is best for hot metal patinas and should be warmed
slightly to allow the wax to grab onto the pores of the patination
right down to the metal. This also needs two applications and should
be allowed to dry for at least two hours before buffing.
I've used both and the pieces still look as nice as the day I made
You might take a look at Japanese Patina
M E T A L W E R X
School for Jewelry and the Metalarts
50 Guinan St.
Waltham, MA 02451
781 891 3854