What glaze actually does
Before glazing, most pieces are first fired to a porous state called bisque. Bisque ware absorbs water, which is what lets glaze grip the surface. During the later glaze firing, the coating melts and fuses to the clay. After cooling, the surface is a hard, glassy layer that can be matte or glossy depending on the recipe.
Read the manufacturer's range
Every commercial glaze is formulated to mature within a specific temperature range, usually given as a cone number. Applying a glaze and firing it outside that range is a common reason results look wrong. The container label is the authoritative source for the glaze you are using.
The three application methods
Dipping
The piece is briefly submerged in a bucket of mixed glaze and lifted out. Dipping gives one of the most even coats and is fast once the glaze is mixed to the right consistency. It does require enough glaze to fill a container deep enough for the work.
Brushing
Glaze is painted on with a soft brush, usually in two or three coats with drying time between them. Brushing uses the least material and suits small batches, which is why bottled brush-on glazes are popular for home use. The trade-off is that even coverage takes more care than dipping.
Pouring
Glaze is poured over the surface or into a hollow form and tipped out. Pouring is useful for the inside of vases and pitchers that are hard to dip cleanly, and it is often combined with dipping the outside.
- Even coverage
- Dipping is usually the most consistent; brushing depends most on technique.
- Material used
- Brushing typically uses the least glaze; dipping needs the most on hand at once.
- Best for
- Pouring suits interiors of narrow forms that are awkward to dip.
Keeping the kiln shelf clean
Wipe glaze off the bottom of each piece, and off a small margin up the side, before firing. Melted glaze that touches the shelf will fuse the piece in place and can damage both the work and the shelf. Wax resist or simply a clean damp sponge are common ways to keep the foot bare.
Food safety
Not every glaze is suitable for surfaces that contact food or drink. If you intend to make functional ware, choose glazes the manufacturer states are food-safe and follow their firing instructions. When the status of a glaze is uncertain, treat the piece as decorative rather than guessing.
Common beginner faults
- Crawling: glaze pulls away from the surface in bare patches, often from dust or oils on the bisque.
- Pinholing: small holes left where gases escaped during firing.
- Running: a coat applied too thickly can flow down and pool at the base.
Handling bisque with clean hands and applying an even, moderate coat prevents many of these. For a broad technical overview, the public reference on ceramic glaze is a useful background read.