Materials Monday: Vocabulary
- , by Haley Stanaford
- 2 min reading time
A lot of words get thrown out when talking about glazes and raw materials and it seems like it’s just expected that you know what is being talked about! But do not fret! Here are some of the most common terms used when talking about raw materials.
Clay
Clay, in the raw material sense, refers to mined materials of pure clays called Kaolins. These are used in glaze and clay body recipes to impart plasticity and work as suspenders in glaze slurries, meaning the particles are able to float through the liquid rather than fall directly to the bottom. Some materials that are clays include Grolleg, EPK, and Tile #6.
Ball Clay
Ball clay is clay but with more impurities in it, making it a little less refined. When these are used in recipes, they end up bringing more elements and compounds to the recipes than clays, which affects the chemical make up of the glaze. Some materials that are ball clays include OM4 and XXSaggar.
Feldspar
Feldspars are a type of mined material that is a mixture of certain elements and compounds. These are used in glazes to help the glaze melt. You may hear feldspar connected to another word like Potash Feldspar, which just means it is Potassium heavy, or Soda Feldspar, meaning it is sodium heavy. Some feldspars include G200 and Minspar.
Silica
Silica is a necessity in glazes, acting as the glass former. Silica can be provided to a glaze mixture from different materials but can also be provided (somewhat) purely. One brand name for this material is Sil-Co-Sil.
Opacifier
Opacifiers are used in glazes to opacify them, or make them opaque rather than translucent. Adding an opacifier to a clear glaze turns it white. Adding an opacifier and a colorant to a glaze turns it an opaque color. Some opacifiers include Ultrox and Tin Oxide.
Frit
Frits are man made mixtures of materials used to make glazes that were fired and then ground into a powder. This process is called fritting. These help when making glazes so you don’t have to add so many materials in and help those materials dissolve into the slurry. There are a lot of frits that offer different chemical makeups like Frit 3124, Frit 3134, Frit 3110, and more!
Colorants
Colorants are materials that are an additive in a glaze to make it a different color. Colorants do not affect the chemical reactions of the glaze, meaning any colorant can be added to any base glaze to achieve different results. Some colorants include Red Iron Oxide, Chrome Oxide, and Cobalt Carbonate.
You can read more in depth about each of these categories, and more, in digitalfire’s glossary.
Haley Stanaford is currently a Post Baccalaureate student in ceramics at the University of Kansas where she is currently taking a Clay and Glaze Formulation taught by Colby Charpentier in addition to her studio practice. She also is a Sales Representative at Bracker’s Good Earth Clays in Lawrence, Kansas.
