It would help if you posted a picture of your existing patina.

That said, it's usually a layer process. Depending on what the patina you have looks like, that will determine the colors of the layers you lay down. For instance, on parts I did on my '46, I used black, then red oxide, then blue over top. I left the red a little wet before I put the blue on, so the blue cracked and left a bit of patina that way as well. Then once it was all dry I sanded through where I wanted the under-layers to show, sanding carefully with 400 or 600, until it looked as I wanted. When I was done I moved up to 2000 to smooth everything out, then used "blue diamond" polish on top for a bit of sheen. It worked great.


1946 GMC Pickup - S-10 Frame, 455 Buick, TH400, original patina.

My 46 GMC on Photobucket