While I am at it I thought I would also mention how I weather brass and copper surfaces.To make brass
look like weathered copper I spray thin washes of burnt umber gesso followed by washes of black gesso mixed with flow medium.
To make brass look weathered I spray just with the black gesso.
I use gesso because it will stick to just about anything.All my experience has been with the liquitex brand of gesso and the Jo Sonja brand of acrylics.I dont know if the same results can be achieved with other brands.As I have mentioned before I was intrducted to Jo Sonja in my bird painting days and I really like it because you have complete control over the shine.It dries absolutely flat but you can mix in your own mediums such as varnish,retarder ,flow medium etc...
Take a look at the Model A Ford truck that I weathered for the Nieuport diorama as most of the shiny parts are copper or brass.
