Frits are parts of a glaze recipe that have been melted and ground to be added into a new glaze recipe. Frit 5301 is a material that is great for high thermal expansion crackle glazes. It can also help with shivering in other glazes. This product was formerly called Frit 4101.
Information gathered from
Digitalfire Ceramic Materials Database and The Potter's Dictionary of Materials and Techniques by Frank Hamer.
