google Biz Littell Vapor Fuming
thanks for your data!!
Mark, I have noticed the lusters but didn't know about their toxicity and smell (and their prices) thanks!
Marcia: fume with flame work / torch? like silver fume, but fuming what?...or how?
Am I correct in assuming that high silica glaze with titanium dioxide, plus CuO can be the solution!? (or I am building a bomb here!!?)(I imagine that the black slip is to show off the iridescence even further, or does some contribution?)
Below is from Gary ferguson's Raku Newsletter.
* Glazing *
There was a question emailed to me after last month's issue as to "What is Vapor Glazing."
So I did a little research and discovered an old issue of Clay Times - March/April 2001 that had an article covering Vapor Glazing by Biz Littell. His technique is named "Kosai ware" which means "hue of light" and involves the use of precious metals such as gold and platinum or special salts such as Stannous Chloride.
His process is to first bisque fire the piece, then glaze fire the piece to cone 04. Then the piece is fired a third time to about 1000F at which point the kiln is opened to cool down to about 800F. One to two tablespoons of stannous chloride crystals are quickly poured on the hot kiln shelf around the pieces (but not on the pieces). Then the kiln is closed for a few minutes to give the salts time to fume the pieces.
This colorant effect is more permanent that the standard Raku copper matte flashing effect.
These chemicals are apparently very corrosive so it is critical that the proper safety equipment is used - respirator, mask, gloves, etc.