Blisters

Blisters

Blisters are a common enamel defect, which is characterized by appearance of circular holes & bubbles in a cooled enameled surface.

Description of enamel defect

Blisters are a common enamel defect, which is characterized by appearance of circular holes & bubbles in a cooled enameled surface.

Occurrence

May occur as a group, cluster or line of blisters.

Possible Causes

Blisters are typically caused by gas evolution during firing, as a consequence of :

  • Poor steel quality
  • Scratches or damage on base steel
  • Large welding seams
  • Insufficient cleaning
  • Over pickling
  • Over blasting
  • Impurities in enamel
  • Too thick enamel film
  • Too high viscous frits
  • Contamination of furnace atmosphere
  • Under firing

Author

  • Ronald Ditmer

    Ronald Ditmer is the founder and managing director of Ditmer Trading & Consulting BV. Involved in the porcelain enameling industry since 1984 and specialized in setting-up complete enameling plants, designing enameling equipment and troubleshooting enameling processes & equipment.

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