Gear Up and Mix Right

Using the right protective equipment and mixing glaze to the correct consistency are the two habits that keep you safe and produce consistent results.

PPE for Glazing

Gloves: Nitrile disposable gloves whenever handling raw oxides, mixing from powder, or doing extended dipping sessions. Not always needed for quick brush application of commercial liquid glazes.

Respirator (N95 or P100): Essential when mixing glaze from dry powder or when sanding bisqueware. Not needed for applying pre-mixed liquid glazes in a well-ventilated space.

Apron: Glaze stains clothing permanently after firing. Always wear an apron.

Eye protection: When mixing dry materials that generate airborne powder.

Mixing Commercial Liquid Glazes

Commercial glazes settle over time: the heavy particles sink and a layer of clear liquid sits on top. Before any application:

1. Stir thoroughly with a stick or a drill with a paint-mixing attachment. The goal is a completely uniform suspension with no lumps on the bottom.
2. Check consistency: most dipping and pouring glazes should be roughly the consistency of whole milk or thin cream. Brushing glazes can be slightly thicker.
3. If the glaze is too thick, add small amounts of water and stir. If too thin, leave the lid off for a day to evaporate some water, or add more dry material.

The Specific Gravity Test

Professional potters use a hydrometer to measure specific gravity: the density of the glaze relative to water. A reading of 1.4–1.5 is typical for a dipping glaze. If you glaze regularly, a hydrometer saves guesswork and produces consistent results every time.

Consistency Tuning Routine

When a bucket misbehaves:

• If coverage is thin: check specific gravity and evaporate or add dry material
• If runs are common: check if SG is too high and dilute in small increments
• Record SG alongside firing results in a notebook

Small, logged tweaks turn glazing from guesswork into a repeatable process.

Down the Rabbit Hole

The NIOSH air filtration rating system classifies the N95 and P100 respirators recommended for mixing dry glaze powders. For more on the density measurement that keeps glaze consistency reliable, the Wikipedia article on specific gravity explains the science behind the hydrometer readings potters rely on.

Common Mistakes and Quick Fixes

• Stirring only the top half of the bucket: Scrape the bottom every time or your glaze results will shift through the day.
• Making large water adjustments at once: Add water in small measured amounts and log each change.
• Skipping notes because “I will remember”: You will not. Write down specific gravity, application method, and firing result.
• Changing multiple variables together: Adjust only one variable per batch test so cause and effect stays clear.

Practice Exercise

Take one commercial glaze bucket and run a controlled consistency test. Measure SG, dip three test tiles at 2, 3, and 4 seconds, then fire and compare. This single exercise teaches more about glaze control than weeks of guesswork.