Clay Quality Assurance

• Expertise
  While we have a wealth of collective clay experience throughout the Laguna Clay Company, Jon Pacini is our overall clay manager. He started with Westwood Clay (now part of Laguna) over 25 years ago, testing clay formulations and glaze formulations under the tutelage of Susan Peterson. Since then, and with Jon Brooks, he has successfully overseen the production of more clay for art potters than any other living person. He is extremely knowledgeable.

• Formulations
  Our clay bodies have been formulated in a variety of different ways to perform extremely well for various different functions. In addition to the fact that they have withstood the test of time, they are also evaluated in scientific ways to assure outstanding performance. For example, we use a dilatometer in our lab which graphs expansion and contraction of clay bodies throughout the entire heating and cooling cycles of a firing. Among other things, this helps us to determine if the coefficient of expansion is compatible with common glazes that are used by art potters. It also helps us to determine the amount of crystobolite that is formed in a clay during the firing process which tells us how susceptible it is to thermal shock and if it is suitable for ovenware, for example.

• Batching and Mixing Procedures
  Many years of practice and experience have honed this aspect down to a science. Each batch is carefully pulled and assigned a consecutive 5 digit batch number. The first digit designates which pug mill the batch will be made in, 1-4 California, 5-7 Ohio, 8 Florida. The next 4 digits are the sequence number starting with 0001 and ending 9999. A paper trail follows every batch of clay from the time the bags are stacked in the batching yard to the time the clay is shipped. Amounts of each material are logged into a form as well as the amount of water used per batch. The yield from any given batch is also recorded. Penetrometer readings are taken and recorded at the mixer stage and at the pugged stage to assure the correct consistency. A record of these readings are also kept.
• Testing Procedures
  A 2 lb sample is taken from each batch of clay and marked with the batch number. Standard sized bars are made and stamped with the batch number. Each test bar is examined before and after being fired to measure deformation, shrinkage and warpage. They are also visually tested for color and texture. Results are recorded before the clay is released for shipment
• Our Commitment to You Our goal is to offer you the best performing, highest quality, and most consistent clay that you will be able to find anywhere. The procedures and people that we have put in place makes this goal highly achievable and we are ready to prove it to you.