Ray Gonzalez on sun 22 jul 01
I am NOT trying to start a debate on the use of lead in a glaze. Let me express that the uses of this glaze will solely be on a sculptural level thus nonfunctional. The below listed glaze has not only Lead Bisilicate (75%!) but Barium as well. Lets all glaze our mugs and bowls with this one! That out of the way..
I have been looking for one of Otto (Heinos?) glazes for a little while now. Well much to my surprise, while casually looking through my copy of Val Cushings handbook, he has it listed! Well some facsimile thereof. He mentions that it works almost exactly like the original. I have seen this glaze used and it is the most attractive glaze (if you are in to lichens and the like sculptural glazes.) I was unable to appropriate the glaze at the time and this began my search. I had a few hints. I will remark after I list the glaze. Here is the glaze as it appears in the handbook:
Ottos Texture revised 5/90 ^06-^04
Lead Bisilicate 73.91
Soda Ash 3.33
Barium Carbonate 8.59
Add Chrome ox. 8.0
Comments: This one works ALMOST exactly like the original. Gives a much darker red when fired to ^04 Greenish black if thin, Yellow-orange-red in intermediate thickness. Apply very thickly- does not run. Very textured glaze. Not for anything used with food! You should be able to sub Ferro 3403 for the lead bisilicate.
okay here are my hints on this one!
A professor in college mixed up a batch for a student but did not give him the recipe. It was extremely chrome green when wet. The student mentioned that it was almost all lead and EPK and "some other stuff." He also mentioned that it was "Ottos 'something.'" As I recall the professor used lead carbonate. This is the reason that I question whether or not it is the same glaze.
If anyone has the original Ottos Texture I would greatly appreciate it. Also, I am interested not necessarily in lead bearing glazes but in lichens and textural low or high fire glazes if anyone has any to offer. I will be testing this one this week in a bisque load.