Caroline R Posted Monday at 08:35 PM Report Share Posted Monday at 08:35 PM Hi all, I have a question about a test one of my students had with her Juicy Fruit test glaze fired in cone 6 oxidation. We were testing colorants on the Juicy Fruit base glaze and got some interesting results but noticed some intense dark coloring on the clay that appeared something like flashing as the colorant increased. What could this be? Please see photos. We had a kiln full of glaze tests and noticed that it happened to some other people in a less extreme way, but there was no common denominator that I can think of. Unfortunately, I am not sure if the pieces were next to each other because I did not load/unload the kiln. We are using a cone 10 stoneware clay body recipe mixed in house. ___________________________________ Juicy Fruit Base Glaze Recipe: Neph Sye- 44.5 Silica- 10.9 Whiting- 10 Kaolin- 9.1 Frit 3124- 8.2 Lithium Carb- 8.2 Soda Ash- 9.1 Bentonite- 2 ___________________________________ Colorant in order from left to right: Chrome Oxide- 0.125% Chrome Oxide- 0.5% Chrome Oxide- 1% Chrome Oxide- 2% Chrome Oxide- 4% ___________________________________ Please let me know what yall think. Thanks!! Caroline Quote Link to comment Share on other sites More sharing options...
Min Posted Monday at 09:51 PM Report Share Posted Monday at 09:51 PM It's flashing from the super high amount of sodium in the glaze. (and probably the cause of the crazing too) Rae Reich and Callie Beller Diesel 2 Quote Link to comment Share on other sites More sharing options...
Kelly in AK Posted Tuesday at 07:53 AM Report Share Posted Tuesday at 07:53 AM Particularly from the soda ash, which is soluble and migrates through the bisque ware when you glaze. Rae Reich 1 Quote Link to comment Share on other sites More sharing options...
Caroline R Posted Tuesday at 01:13 PM Author Report Share Posted Tuesday at 01:13 PM @Min thanks. I learned something new today then. I was aware you could get flashing like that in an electric kiln! It definitely got worse with the increase in chrome oxide but it doesn’t sound like it has anything to do with the colorant but more with the soda ash. Quote Link to comment Share on other sites More sharing options...
Min Posted Tuesday at 02:46 PM Report Share Posted Tuesday at 02:46 PM (edited) Chrome is volatile, it will flash too. Think of a white glaze opacified with tin, if you have a glaze containing chrome near it while firing the white can flash pink from the chrome. Edited Tuesday at 04:50 PM by Min typo mistake Caroline R 1 Quote Link to comment Share on other sites More sharing options...
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