Heavy Glaze Defect in Ceramics: Causes & Analysis
Learn about heavy glaze defect in ceramics, its causes like over-application and over-firing, and how to fix and prevent it.
Heavy Glaze Defect in Ceramics: Causes & Analysis
Overview
Heavy glaze defect occurs when an excessive amount of glaze is applied to ceramics, causing it to run off to the bottom or corners during firing. This defect is also referred to as glaze drop.
Primary Causes
Over-application during spraying: When glaze is applied too thickly, it accumulates in certain areas and flows down during firing.
Over-firing: Excessive kiln temperatures cause the glaze to melt more than intended, leading to increased flow and pooling.
Over-grinding of glaze raw materials: This reduces viscosity, making glaze more prone to running during firing.
Prevention Measures
The following steps can help control and prevent heavy glaze defects:
Closely monitor and maintain proper glaze thickness during application
Ensure even and consistent glazing to prevent excess accumulation
Implement proper control of glaze preparation and firing parameters
Corrective Actions
Several corrective measures can be implemented to address heavy glaze defects:
Sponging: Remove excess glaze from the bottom and corners of wares before firing to significantly reduce glaze runoff.
Design modifications: Round the edges and bottoms of wares during design and production, as sharp corners tend to trap more glaze and cause pooling.
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CeramicNinja
Ceramic industry professional & content contributor.
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