Phil... you are a font of knowledge! I’m glazing now ... all your information perks thought & answers a plethora of questions I didn’t know I had! Thank you(:
Kate, Thank you and if any of your questions could be topics for future videos, please let us know! If you are thinking of the question, many will appreciated an answer! Thank you for your continued support and encouragement.
Thank you for this explanation! I have learnt a lot from this channel. Do you have any thoughts on single firing? It would be great to learn more about that in a video. I have been told that single firing makes the ware stronger - is that true? If so, why? Thanks.
Hi Red, Thanks for your email. Single firing is a traditional technique that basically combines a bisque firing and a glaze firing into one firing. I can’t imagine why single firing would produce stronger pots, if the pots are fired at the same schedule to the same final high temperature. The sintering and densification that occur at the high temperatures are what give the pots their final fired strength. I personally don’t favor single firing for my work because, except for not having to perform a separate firing, I don’t see any great advantage. It is still necessary to include a slow, bisque-firing portion at the beginning of the firing. With a separate bisque firing there is the opportunity to examine pots for defects before glazing, and the bisqued pots are more easily handled for glazing, allowing more variation in glaze application techniques. Varying the bisque firing temperature can also provide the opportunity to explore different glaze absorption rates and final thicknesses. Phil
I have never heard this explained or read about it. Fantastic!.. so a 'tomato' red glaze with 11% red iron oxide e.g. glazy.org/recipes/29031 .... is the red from the red iron oxide in suspension or from the bone ash?... I fire this in reduction and it is still red
Hi Michael, Thanks for your email. The red color, and the opaque nature of the glaze, would be from the iron oxide in suspension. I’m not sure exactly what role the bone ash (calcium phosphate) plays, but it apparently intensifies the red color. My guess would be that the bone ash helps to stabilize the iron oxide in the red (ferric) state. Under normal conditions, when heated to stoneware temperatures, and in reduction, the red iron oxide would change into black iron oxide, and the red color would be darkened or mostly lost. Phil
