Amaco's Arroya White Glaze can be used to create a crackle texture that gives your work a unique "carved" effect when fired. Use the arroya glaze over glossy and matte unfired glazes. Arroya glazes are best applied with a fully glaze soaked brush and spread all-over for full coverage, or use a sponge to blot the glaze on. The heavier the application, the larger the break-up effect and the more matte the finish. Try using the white arroya glaze over a dark blue glaze.
Here's what Amaco has to say about Arroya glaze:
Arroya White is a special glaze designed to make interesting patterns in almost any glaze from cone 05 to 6. Arroya glazes are applied over the normal 3 coats of any brushing glaze and may be applied in 2 or 3 coats. Two coats will develop a fine crack pattern and three coats will develop a larger pattern. Coats of glaze need to be applied as soon as the previous coat has lost its sheen. This is because the Arroya glazes need to mud crack before the piece is placed in the kiln. If the glaze doesn’t crack outside the kiln, no pattern will be seen on the fired piece. Set the glazed piece on the kiln shelf it will be fired on to avoid having to handle the piece after the glaze has cracked and dried.
Fire the piece to the cone value of the base glaze. The Arroya will take on the character of the base glaze. A stiff non-flowing glaze will have a very distinct pattern and a soft fluid glaze will blend with the Arroya for a very natural look. The Soft White and Soft Black work just like the other Arroya glazes but are softer and will
melt into base glazes better. You will get some wonderful results on almost every base glaze you try.
(NOTE: Do not apply Arroyas to dipping glazed pots. Arroyas contain a lot of binder which is needed to keep the glaze attached to the piece when the glaze cracks. Applying Arroyas to a dipping glaze without binder will cause the glaze to flake off the pot and fuse to the kiln
shelf.)
Recommended firing temperature for Arroya glazes is Cone 05 (1911°F, 1044°C). These glazes must be applied to mature Cone 04 (1971°F, 1077°C) bisque.
