Since mined clay is a natural material, its characteristics tend to vary from time to time. It is our job to notice these changes and to make the necessary adjustments to our clay bodies before our customers notice any differences. This can only be done by thorough and continuous testing. We test every pallet of every truck load of raw clay material that we receive. We also do tests for every batch of 30 boxes that we produce. Our standard tests are for colour, wet-to-dry shrinkage, total shrinkage and absorption. We also make sure that the coefficient of expansion stays within a certain range to help ensure good glaze fit.

First, all of the raw materials are put through a 40-inch diameter, 35-mesh, vibrating screen to eliminate unwanted materials such as lime. This is a very important step. In certain clay bodies with a dry weight of 1200 pounds or so we will screen off up to 30 pounds of unwanted materials which could cause serious problems for the potter. The dry materials are screened directly into an Eirich high-intensive clay mixer. This is a stainless steel, fully automatic machine with incredible mixing capabilities. Although we take longer, a 1200-pound batch of clay can be made completely homogeneous in 45 seconds. Even tiny additions, such as one pound of a particular material, will be perfectly blended throughout a batch. The addition of water is computer controlled down to one-tenth of a liter and is then blended completely in the Eirich mixer. The clay moves by conveyor to an A.J. Wahl pugmill, which has excellent deairing and compression capabilities to ensure that the clay is free of air and laminations. Any part of Tucker’s mixing system which touches clay is either stainless steel or nylon, ensuring that our porcelains will never have any iron contamination from the equipment. This investment in some of the best mixing equipment available demonstrates Tucker’s commitment to the production of excellent trouble-free clay bodies.