Supplies. clays, glazes, tools, raw materials, frits, kilns, pottery wheels, refractories, extruders, slabrollers, and more! view the links page to view our suppliers online catalogs. orders/payment. we sell wholesale and retail. we accept cash, checks, visa, mastercard and discover. pick up orders may be called in ahead of time. we ship postal ... Boron-based frits are typically used in earthenware glazes when a lead-free glaze is required. while these frits donu2019t produce quite the bright colors that lead does, they do carry the added bonus of not being terribly toxic to both the glaze mixer, and the person eating food off of u2026 Northern california's complete ceramic & pottery supply company. we manufacturer over 20 clay planet signature ceramic clay bodies in house, and make nearly 400 colors of western ceramic glaze, underglazes, & engobes.