This chapter discusses how to finish your enamels with grinding and sanding for various situations, discusses the various enamel finishes such as sugar fire, mounting enamels onto something or other enamels, finishing metal and the Raku firing process, which is a finish to the Raku process.
Liver of Sulfur Tips and TrickS
If you want to use Liver of Sulfur and get great patina's in colors, not just black, watch this video by Pam East. My book mentioned Liver of Sulfur, but not nearly in the depth that Pam goes into. Check it out!
This Patinas For Small Studios, a 44 page book by Charles Lewton-Brain, provides many different ways to finish your metal. Charles is a well known educator and writer.
In my first book, Jean Tudor wrote a project on the Raku process. I decided for the second book to make this an LTT mini project, which is on pages 109-110. In both she lists the enamels to use that contain either copper oxide (the best to use) or manganese oxide (the second best to use). In both, she lists unleaded and leaded Thompson Enamel's enamel (of course other brands with these oxides should also work). However, one of the unleaded is labeled incorrectly - Jean has 2910 Oil Gray and she meant 2910 Elan Gray (Oil Gray is 2915).
Here are the results of some testing Jean did with the Manganese Oxide enamels:
Jean suggests that people experiment with the two browns. But the manganese oxides are subtle, giving a sort of delicate nickel or sometimes goldish color. It's not bold like the strong copper that she gets with the copper oxide blues/greens/turquoises. She feels she gets the best manganese results with the vintage leaded color 834 Smoke Gray. When creating with Raku, it's fine to mix leaded and unleaded enamels as there are so many interesting things that happen with breakthrough and other vagaries of the two enamels working together. The best sources to get old Thompson Enamel leaded enamels are in my resource list in the book, but provided here for expediency: E-namels.com and Schlaifer Enameling Supplies.
Jean went back to her old tests, which were all stored in the dark in a closet. What she found was that all the ones with unleaded enamels used for the Raku coloration lost their color, but all the ones with leaded enamels were fine. Note that all the pieces she has displayed in her house with either leaded or unleaded enamels were just fine.
I am trying to do some research on why the color sometimes fade. In any case, raku pieces should not be displayed where they get heated by something like direct sunlght or possibly indoor heating vents; Jean is convinced it's the heat, not the light that is a factor. I called a local raku potter, Tom Neugebauer who I thought might give some insight. He says this can happen with Raku pottery too, although he never uses leaded glazes so he cannot comment on that aspect. However, he feels it's the air, not the light or heat and he knows it's the oxygen in the air that causes the copper in luster glazes, over time, to re-oxidize and turn green/ muddy (Tom found this article about raku on pottery). I also called Cullen Hackler, a ceramic engineer, the Managing Director of The Enamelist Society and the Technical Director of the Procelain Enamel Institute, who says he agrees, it's the air, but specifically it's the oxygen in the air - remember that Raku is done by quickly putting the piece in an oxygen reduction environment so it makes sense that adding the oxygen back in would change the colors. Tom feels that the deeper the color goes (maybe by putting the piece faster into the oxygen reduction environment and keeping out more air for a longer period of time) the less it may fade. He also has impirical experience that wrapping a Raku piece in bubble wrap or plastic will remove the coloration (maybe because of a chemical in the plastic???). Both Tom and Cullen agree that sealing the Raku will deprive it of air and thus most probably hold the color. The sealant can be something like wax, which is fine over enamel.
This is an on going search for more information so please come back again to see if more has been added. If you have more information, please contact me.