I want to fabricate an architecturally pleasing box out of sheet metal to hide an exterior metal smokestack. I want to add some interesting details and then mask the fact that it is made of sheet metal somehow. It is 25 feet up, so no one will look closely. Is there a chemical I can use to create a natural rust patina?
As a general rule, it's better to use the material you want to look at vs.trying to modify the pig's ear. Given the latter, what metal are you hoping to patinate?
The best material would be Cor-Ten steel, which develops a coating of rust which becomes passive. Originally developed as a structural steel that would not require sandblasting/painting. May be difficult to obtain in small amounts. Patina on virtually any other metal will require coating of some sort to maintain a steady state, and the coating is subject to breakdown. What about plaster, concrete or ceramic molds/applique?
