Tin Foil II Crystalline Glaze
Recipe
Notes
From Crystal Glazes Book 2 by Fara Shimbo, page 66. Purpose: To alter the shape of the crystals from broad "geranium" petals to narrow "dandelion" or "aster" petals by using tin. Tin Foil 2 is an excellent low-titanium glaze; in fact, it makes an excellent no-titanium glaze if you just leave the titanium out. On porcelain, it has a very transparent ground, though this does not necessarily hold true on stoneware. I decided to try adding tin to the glaze when I noticed the very interesting effect that chrome-tin pinks had on the crystals; the nearly complete change in character from a flower to a lily pad. Most of this effectis due to chrome, but with chrome being a powerful colorant I didn't want to use it. Tin is generally thought of as an opacifier, but in small amounts like this its only real effect is to change the shape of the crystals, so instead of a daisy, one has a dandelion. Tin Foil 2 crystals are very opaque which makes this an excellent glaze for use with copper colorants. The ground is often slightly yellowish by itself, often varying the color responseof cobalt toward cyan. Tin Foil has always been an exceptionally reliable glaze for me. I found out that the original would go down to D5 quite by accident one day when the power went out at that temperature. After two hours soaking at 1000°C, I had lovely crystals about 2 cm in diameter. It's been my experience that crystal growth slows down proportionally to the amount of tin in the glaze; so much so that if you add about 4% tin you can grow only a few crystals no more than a centimetre in diameter even after a three-hour soak.
Description
Cone 6-9 - Dolomite, tin, titanium variant