In the Studio: Glaze Lab: Making Test Tiles Dan Ingersoll

Appears in the Jul/Aug 2024 issue of Pottery Making Illustrated.

On the surface, my process for making test tiles may seem like a lot of work. However, the “work” is a one-time investment that pays off with a quick, efficient, and versatile process, especially if you are not comfortable throwing tile blanks or do not have access to an extruder. 

The Tool 

Start by making a double-bevel tool (1). In the 2023 July/August issue of Pottery Making Illustrated, I described how to upcycle flat, stainless-steel wire from windshield wipers to make a variety of clay cutting and carving tools. One of them was this cutting tool. It is simply a wiper wire that is heated, bent just shy of a 45° angle, inset, and glued into a small block of wood. I use this tool combined with a template to create test tiles. 

The Template 

The template can be sized to fit personal preferences. Using a ¼-inch (0.6-cm) piece of plywood cut a 5 × 24-inch (12.7 × 61-cm) piece on a table saw. Alternatively, you could make the template using an X-Acto knife and mat board if you don’t have access to woodworking tools. Make 3-inch (7.6-cm) cuts into the template at 2-inch (5-cm) intervals to serve as a cut guide for tiles. I used my table saw for this, however, a handheld jigsaw would also work. Finally, make hole guides in the center of each of the 2-inch (5-cm) spaces about ¼inch (0.6 cm) from the edge to provide a hanging option for tile storage (2). 

Creating Test Tiles 

With the bevel cutter and template in hand, you are ready to make test tiles. First, using a rolling pin and thickness gauges (or a slab roller), roll out a slab that is at least 6 inches (15.2 cm) wide and 24 inches (61 cm) long. The thickness of your tiles should reflect the thickness of the work you make. Lay your template on top of the clay and cut out around it using a fettling knife (3). 

If you would like some texture on your tiles, roll, impress, or stamp the area of the tile that will become the lower half of the finished tile (4). If you add texture, for the next step, you will need to flip the clay over, so the texture side is down. Once flipped, position the straight edge so it covers the slab, and then using the guide cuts, mark the slab into 2-inch (5.1-cm) tiles without cutting through it (5). 

Next, position the template such that it will guide the bevel-cutting tool so that it makes a cut about 1½ inches (3.8 cm) (the foot of the tile) from what will be the bottom edge. Using the straight edge as a guide, draw the cutting tool across the surface of the clay to create a hinge (6). 

Brush Magic Water (to make, mix 1 gallon water, 3 tablespoons liquid sodium silicate, and 1½ teaspoons soda ash) onto the beveled cut. Now, slide the template under the clay until it is just under the cut/hinge, raise it up to create a 45° angle on the slab (7), and then continue past 45° so the tile will balance in the upright position (8). Apply good pressure to create a tight, firm joint. 

Finishing 

To complete the process, wait until the length of the tiles stiffens up a bit, then, using the guidelines you made previously, cut the tiles apart. 

If you desire a glaze stop, place a small wooden blank (that is a ½ inch (1.3 cm) shorter than the height of the current tile) against the tile and level with the top. With the tile in the upright position, lean it back just a bit, and apply downward pressure to make a ridge and complete the tile (9). 

Dan Ingersoll taught K–12 art in the public school system for 30 years (17 of them teaching high school ceramics). Following retirement, he was a lecturer in art education at the University of Wisconsin-Eau Claire for three years. He is currently retired and pursuing his passion for clay in a small basement studio and wood firing with a fellow potter. His work has been shown on both regional and national levels.