Chapter 30. Black Specking Problems—A Panel Presentation

  1. John B. Wachtman Jr.
  1. Daniel Luehrs1 and
  2. Robin W. Watson2

Published Online: 28 MAR 2008

DOI: 10.1002/9780470310489.ch30

Proceedings of the 49th Porcelain Enamel Institute Technical Forum: Ceramic Engineering and Science Proceedings, Volume 9, Issue 5/6

Proceedings of the 49th Porcelain Enamel Institute Technical Forum: Ceramic Engineering and Science Proceedings, Volume 9, Issue 5/6

How to Cite

Luehrs, D. and Watson, R. W. (1988) Black Specking Problems—A Panel Presentation, in Proceedings of the 49th Porcelain Enamel Institute Technical Forum: Ceramic Engineering and Science Proceedings, Volume 9, Issue 5/6 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310489.ch30

Author Information

  1. 1

    Magic Chef 740 King Edward Ave. Cleveland, TN 37311

  2. 2

    Norge Co. Lyerla Dr. Herrin, IL 62948

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780470374795

Online ISBN: 9780470310489

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Keywords:

  • porcelain;
  • pretreatment;
  • eliminate;
  • fish scale;
  • compounds

Summary

According to an ancient Chinese proverb, courtesy of Mr. Luehrs, “the dreaded black speck will always haunt the porcelain enamel.” Despite this, Mr. Luehrs successfully combats the dreaded black speck by giving careful attention to his substrate, pretreatment, frit system and housekeeping—keeping everything clean is of the utmost importance. Mr. Watson has given care to all of these areas and is still nonetheless plagued. He has discovered, however, that the bubble structure of the powder coat, its viscosity (of the fired finish coat) at melting temperatures, and the finish coat thickness all are factors in black specking.