How to Glaze Pottery for Kiln Firing: Beginner's Guide | ProKilnSupply

How to Glaze Pottery for Kiln Firing: A Beginner's Complete Guide

Glazing is where most beginner potters run into trouble. The clay work goes smoothly, the bisque firing looks great — and then a pooled glaze, a bare patch, or pieces fused to the kiln shelf ruins a firing that took weeks to produce. Here's how to glaze well from the start.

What Glaze Actually Is

Ceramic glaze is a thin layer of glass-forming materials — silica, alumina, and flux compounds — mixed with water and applied to bisqueware. During firing, the glaze materials melt and flow across the surface of the piece, forming a glassy coating that is decorative, waterproof, and (with the right formulation) food-safe.

Glazes are not paint. They look nothing like their final fired color when applied wet. The transformation during firing is dramatic and sometimes unpredictable — which is part of what makes ceramics so compelling.

Always Wax the Foot Ring

Before applying any glaze, apply wax resist to the foot ring (the bottom rim of the piece) and the entire bottom surface. Wax resist is a liquid applied with a brush that repels glaze. Once waxed, glaze applied to the waxed area beads off and can be wiped away.

This is the single most important glazing habit to develop. A single drop of glaze on the kiln shelf will bond permanently during firing, destroying your piece, your shelf, or both.

Application Methods

Brush application: The most accessible method for beginners. Use a soft, wide brush and apply glaze in even strokes — typically three coats, allowing each coat to dry fully before the next. Overlapping brushstrokes create uneven thickness, which shows in the fired result.

Dipping: Holding the piece and submerging it in a bucket of glaze for a few seconds. Creates an extremely even coat in one step. Requires enough glaze to fill a bucket — practical for production potters with dedicated glaze buckets, less practical for beginners with small glaze quantities.

Pouring: Pouring glaze over the exterior of a piece while holding it over a catch basin. Good for the outside of tall pieces. Often combined with dipping the interior separately.

Spraying: Using an airbrush or spray gun to apply glaze. Creates very even, controlled coats and allows subtle layering of multiple glazes. Requires spray equipment, a spray booth, and a respirator.

Glaze Thickness Matters Enormously

Too thin: The glaze doesn't cover properly, results in bare or matte patches, and colors are washed out. Too thick: The glaze crawls (pulls away from the surface during firing), blisters, or runs excessively and drips onto your shelf.

The right thickness depends on the specific glaze. Most commercial brush-on glazes are formulated for three coats with a brush. Follow manufacturer instructions and test new glazes on small test tiles before committing them to finished work.

Common Glazing Mistakes

Glazing over a dusty or greasy surface: Glaze won't adhere properly to dirty bisqueware. Handle bisqueware minimally after firing to avoid contaminating the surface with skin oils.

Applying glaze too close to the foot: Leave at least a half-inch of bare clay above the foot ring on any glazed piece, even with wax resist applied.

Mixing incompatible glazes: Not all glazes play well together. When layering two glazes, test the combination on a test tile before using it on finished work. Some combinations create beautiful effects; others crawl, blister, or run excessively.