Here’s my first attempt at the hot patina process. All but one of the chemicals arrived from ArtChemicals, the Cupric Nitrate being on back order. I decided I couldn’t wait and pressed on anyway. I printed labels so I could keep better track of the chemical blends and colors each was supposed to produce. I learned two things right away. The first is this is a complicated process. The second is you really can’t mess it up. I used the method demonstrated by David Marks on his Woodworks show WWK-607.
I started by sanding both sides of the panel with a random orbit sander and 220 grit. I then cleaned the panel with dishsoap and hot water and dried it.
My plan was to lay down a background blend of Traditional Japanese Brown and the orange/brown mixture of Ferric Nitrate/Ferric Chloride, then apply some layers of a Light Green and Traditional Blue patinas. The basic method is to heat the metal to about 220 degrees or the point where water steams when sprayed on, spray on the chemicals, then flame that area. This being a first effort I overheated some areas while underheating others. I also over-flamed some and under-flamed others. Some of the chemicals produce a different color than expected.
You may notice the picture above has a lot of blue and reds and some yellow spots. This was done by design and I was happy with this result. However, the vendor advised me to apply a coat of fine wax (Renaissance) which, unfortunatley, changed the color of the yellow and muted the others. I viewed a video on their website where the demonstrator advised not to wax green or blue patinas, rather to let it cool and apply Permalac laquer. I could not tell from the David Marks DIY page whether I should spray the final coat with water to stop the reaction. He had mentioned spraying off the panel between applications of chemicals, but I am still not clear about this.
In any event, the chemicals continued to react and the panel is much more green than these photos, although it still looks good. I will post more pictures in a later blog, but here are some to give you an idea of the result.
-- tim hill www.newcalshop.com