Jocelyn, In my experience with patinas on copper, they must be sealed
in some way to keep them from continuing to change (albeit more
slowly) in reaction with the environment. Copper is a very reactive
metal, after all.
The patina is just at the very surface level of the piece, so any
type of abrasion (especially brass brushing) will remove it. And,
unless sealed, the copper will continue to react with water in the
air, oils and chemicals on your skin, and anything else it comes into
contact with – changing that lovely purplish color into the more
typically found green verdigris that all copper “wants” to turn.
I’ve made several patinaed copper pieces. For flat pieces (or
reasonably so), I’ve sealed them with Butcher’s Wax and they have
stayed just as designed. For more complex pieces (with nooks and
crannies), I’ve used spray lacquer like Krystal Klear or Rustoleum.
You can use either the matte or the glossy finish, depending on the
effect you desire. For true “invisibility” of your sealant, the way
I’ve found works best is to apply in multiple VERY thin coats –
working outside, spray a mist of lacquer into the air and then pass
your piece through the mist. This avoids “clumping” or “drips” of
Hope this helps!
Handcrafted and Unique Artisan Jewelry