Hi Silica in Ash Glazes

That ratio is not an imbalance. Many glossy glazes have a 9-12 ratio of silica to alumina. A lower ration 4-6 would indicate a matt glaze, for instance; 7-8 a satin, etc. etc.

Regards, June

June thanks for your response. By coincidence I was checking out the Shambhala site last night. That's a far out place you have there. I'm still checking out the recipes and tests but from what I've seen so far you've had some great results. The confusion comes from my failure to get a grip on the role of fluxes and their the relation to the Si:Al ratio. I've been studying many gloss glazes with low flux content so that ratio would inevitably be lower - then I switched my interest to wood ash glazes, which, as you will already know, have a very high flux content, and suddenly I was getting

11, 12, 13:1 ratios. At least my query led me to look up some basic principles thanks to your input. I only started ceramics 8 months ago and already I'm dreaming unity formula, health & safety, throwing techniques and pot design instead of sleeping. . . I think I'm pleasantly addicted. Thanks again pete

The fluxes always add up to 1 in unity formula and really don't have any bearing on the ratio of alumina and silica. They do have input though in that very active fluxes might affect the melt more, making it necessary for you to up the silica and alumina. Then there are those eutectics that beginners may not be prepared for. You create a formula within the limits generally agreed upon for the cone you are aiming for and suddenly the glaze is running off the pot and you can't understand why. Then you do more reading and find you had barium and gersltey borate in there and barium and boron create a eutectic, which creates greater melt when certain ingredients are in combination in a formula. The eutectic causes them to melt at a lower range than they normally would when in combination with other materials. Another lesson learned and you go on to the next one. :-)

Warm regards, June

Pete