Ohio Stoneware ~ How It's Made

8th Jul 2019

The pottery manufacturing process is tedious and consists of many variables. It is not uncommon for any two items to have differences between them. 

Ohio Stoneware has a unique clay formula and a unique glaze formula... both of which help create the quality Ohio Stoneware is so well known for. Many processes are used when making a piece of pottery. Items can be pressed, slip casted, or hand turned on a wheel. Each of these processes take a unique clay and process. 

Here at Ohio Stoneware, first, the raw materials (HTP, flint, and Minspar 200) are received in 50 or 100 pound bags, and are palletized. The raw materials are introduced into the mixer with water and mixed until the required consistency is achieved.

Following the mixing process, the clay is passed through a pug mill to prepare and cut the clay into logs for use in the from presses. The "logs" of clay will vary in size, depending on the product being manufactured. The logs move on to the forming process. 

The slugs are placed on the press fitted with a metal mold, and the items are made one at a time. Many items at Ohio Stoneware are pressed on a spindle press or ram press. There are six forming presses that produce the following goods in a variety of sizes and shapes:  pet feeders (dog bowls), birdbaths, crocks, and flowerpots. The form presses are equipped with metal forms. One is fixed to the top half and the other to the bottom half. The clay logs from the pug mill are placed between the top half and bottom half of the press. When the press is cycled, the two metal forms converge and press the clay into shape. The press is then cleaned and prepared for the next cycle and log. 

A small amount of detail work is completed on the product when it comes out. A finisher cleans the excess flash off, and then the item or "greenware" is sent to a dryer. 

Following the forming process, the product is stored on racks and sent to one of two dryers, where they dry for approximately 16 hours. This process takes much of the moisture out of the piece, taking it from a soft piece of formed clay to a solid shaped item (yet, still very fragile). The product must be completely dry for the glazing to adhere correctly.

Once the drying cycle is complete, the products are glazed one of two ways: an auto glazer or hand spray booth. Both methods use compressed air to spray-glaze the product. The auto glazer is able to spray the inside and outside of the product through two cycles. Hand spraying is completed by employees, and generally only sprays the outside of larger products. From the dryer, it goes to a spray booth, where it is either sprayed by hand or by machine. After the product is glazed, it moves to the one of two kilns to be fired.

A true stoneware is a high fire item, which creates strength. The kilns are heated to 2165°, where the product must stay for a period of time. The firing process lasts 14 hours, from heat-up to cool-down. When the product is removed from the kiln and the items have cooled, it is palletized, packaged with cardboard, shrink wrapped, and prepared for shipping. 

Ohio Stoneware LLC sells their products on a wholesale basis to retailers across the United States.