Mixing glaze and underglaze can lead to fascinating results in ceramic art, but it requires understanding their distinct properties and how they interact. Both are used to add color and texture to pottery, yet they serve different purposes and react differently during firing.

What Are Glaze and Underglaze?

Before diving into the effects of mixing, it’s crucial to understand what glaze and underglaze are. Glaze is a glassy coating applied to pottery to create a waterproof surface and add color or texture. It typically contains silica, alumina, and flux, and it melts during firing to form a smooth, glass-like surface. In contrast, underglaze is a colored decoration applied to pottery before the final glaze is added. It is made from a mix of clay and pigment and remains stable during firing, allowing the final glaze to cover it without altering its appearance.

Can You Mix Glaze and Underglaze?

What Happens When You Mix Them?

Mixing glaze and underglaze can produce unique effects, but the outcome is unpredictable. When combined, the underglaze may alter the glaze’s color, texture, or transparency. This can result in innovative designs or unexpected flaws. For example, mixing might cause the glaze to become more opaque or change color due to the pigments in the underglaze.

Considerations for Successful Mixing

• Test Tiles: Always create test tiles when experimenting with new combinations to observe the results before applying them to your final piece.
• Firing Temperature: Ensure both materials can withstand the same firing temperature. Some underglazes are formulated for low-fire temperatures, while others can handle high-fire conditions.
• Layering: Consider layering rather than mixing. Apply underglaze first, let it dry, and then apply glaze on top. This allows for more control over the final appearance and reduces the risk of unwanted reactions.

How to Apply Underglaze and Glaze Together

Step-by-Step Process

1. Preparation: Start with a bisque-fired piece. Clean the surface to remove any dust or grease that might affect adhesion.
2. Apply Underglaze: Use brushes, sponges, or other tools to apply the underglaze. Allow it to dry completely.
3. Add Glaze: Once the underglaze is dry, apply the glaze over it. Be careful not to disturb the underglaze beneath.
4. Firing: Follow the recommended firing schedule for your materials. Keep in mind that different kilns can produce varying results.

Practical Example

Consider a ceramic mug with a floral design. Use underglaze to paint the flowers with intricate details. After it dries, apply a clear glaze over the entire mug. During firing, the underglaze retains its detailed appearance, and the clear glaze adds a glossy finish, enhancing the design.

Common Mistakes to Avoid

• Overloading: Applying too much underglaze or glaze can cause running or blotching during firing.
• Incompatible Materials: Mixing materials that are not compatible in terms of firing range can lead to defects like cracking or bubbling.
• Skipping Tests: Failing to test combinations can result in unsatisfactory outcomes on finished pieces.

People Also Ask

What Is the Difference Between Glaze and Underglaze?

Glaze is a glassy coating applied to pottery to make it waterproof and add color or texture. Underglaze, however, is a colored decoration applied before glazing. It remains stable during firing, allowing for detailed designs that the glaze can cover without altering.

Can You Use Underglaze on Greenware?

Yes, underglaze can be applied to greenware (unfired clay) as well as bisque ware. When applied to greenware, it becomes part of the clay body after firing, offering a durable and integrated finish.

Does Underglaze Need a Clear Glaze on Top?

While underglaze does not require a glaze on top, applying a clear glaze can enhance its appearance by adding a glossy finish and protecting the design from wear and tear.

How Does Firing Temperature Affect Underglaze?

Firing temperature is crucial for underglaze, as it must be compatible with the clay body and the final glaze. Low-fire underglazes may not survive high temperatures, leading to color changes or damage.

Can You Layer Multiple Underglazes?

Yes, multiple layers of underglaze can be applied to create complex designs. Each layer should be allowed to dry before adding the next to prevent smudging and ensure clarity.

Conclusion

Mixing glaze and underglaze offers a world of creative possibilities in ceramics, but it requires careful consideration and testing. By understanding their properties and experimenting with combinations, artists can achieve unique and beautiful results. For further exploration, consider learning more about the different types of glazes or techniques for applying underglaze to expand your ceramic artistry.