I have bought some sheets of very nice 1.2mm copper and brass few weeks ago. I have punched few circles out of it and made some rings. Few different finishes, very simple and “earthy”. I am not sure how long the finish will last if you start cleaning your ring using different products but if you just wipe it with a cloth so far it has been 7 weeks and they look as they did when I made them. Those finishes are NOT painted! They are created using heat and water. That is it. If they will start rubbing off I will consider putting a coat of clear paint to seal it but I do not like any chemicals on my rings so maybe I don’t have to do that. I can make them in any shape, size etc. I am still playing and experimenting with different heat application to achieve different results. I sold few of them locally the minute I showed them to few friends. I can make one as a custom order.
