CCE Selection & Application of Materials & Equipment for Ceramics 2

Question 1

Which type of kiln atmosphere is essential when firing reduction glazes to achieve metallic luster effects?

Accepted Answer

Reduction atmosphere

Answer

Reduction atmospheres limit oxygen, causing iron and copper oxides in glazes to lose oxygen and produce metallic, iridescent surfaces.

Question 2

What is the primary purpose of adding silica (flint) to a clay body?

Accepted Answer

Control thermal expansion and add strength

Answer

Silica acts as a structural filler that controls thermal expansion coefficients and contributes to the fired strength of the ceramic body.

Question 3

A ceramist notices crazing in a glaze after cooling. What is the most likely cause?

Accepted Answer

Glaze thermal expansion is too high relative to the clay body

Answer

Crazing occurs when glaze contracts more than the clay body on cooling, placing the glaze in tension and causing fine cracks.

Question 4

Which equipment is used to measure the specific gravity of a glaze slop to ensure consistent application thickness?

Accepted Answer

Hydrometer

Answer

A hydrometer measures the specific gravity of a glaze slop, which directly relates to the water-to-material ratio and resulting coat thickness.

Question 5

When selecting a kiln wash, which property is most critical to prevent glaze from bonding to kiln shelves?

Accepted Answer

Non-adhesive surface at high temperatures

Answer

Kiln wash must remain non-adhesive and non-reactive with molten glaze at peak firing temperatures to allow easy removal of ware.

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