MINIMUM PAINT FILM THICKNESS FOR ECONOMICAL PROTECTION OF HOT-ROLLED STEEL AGAINST CORROSION

A TEN-YEAR PAINT EXPOSURE STUDY WAS CONDUCTED TO DETERMINE WHETHER OR NOT THERE IS A MINIMUM OF OPTIMUM PAINT FILM THICKNESS, SUCH AS 5 MILS, FOR THE ECONOMICAL PROTECTION OF HOT-ROLLED STEEL. IN ALL WORK TO DATE, EACH ADDITIONAL MIL OF PAINT THICKNESS HAS BEEN ACCOMPANIED BY AN INCREASE OF ABOUT 20 MONTHS IN PAINT LIFE. IT WAS SHOWN THAT THERE WAS INDEED AN ECONOMIC INITIAL PAINT FILM THICKNESS ABOVE WHICH LING-TERM PROTECTION WAS AFFORDED THROUGHOUT THE ENTIRE STUDY PERIOD. THIS MINIMUM EFFECTUAL THICKNESS, HOWEVER, WAS NOT A CONSTANT, BEING THINNER FOR THE MORE DURABLE AND LESS PERMEABLE PAINTS. IN ADDITION, THIS THICKNESS TENDED TO BE LOWER IN MILDER ENVIRONMENTS, AND TO AN UNEXPECTEDLY LIMITED EXTENT, LOWER ON WELL-PREPARED SURFACES. IT WAS FOUND FAR MORE ECONOMICAL TO APPLY SUFFICIENTLY HEAVY FILMS AT THE BEGINNING RATHER THAN TO UNDERTAKE MORE FREQUENT SUBSEQUENT MAINTENANCE PAINTING. THE ALKYD TENDED TO BE SLIGHTLY MORE ECONOMICAL THAN THE OTHER FIVE GENERIC SYSTEMS. VINYLS GAVE LONG-TERM PROTECTION, BUT REQUIRED WHITE METAL BLAST CLEANING TO AVOID EDGE FAILURE AT THE PANEL SUPPORTS. AT THE SEACOAST, THE MOST EXPENSIVE SURFACE TO PROTECT WAS ONE WHICH HAD BEEN COMPLETELY RUSTED AT THE SITE, BLAST CLEANED AND PAINTED. INTACT MILL SCALE SHOWED LOWEST COST, BUT CANNOT BE PRESUMED TO BE COMMERCIALLY AVAILABLE. THE NEED WAS SHOWN FOR A THOROUGH INVESTIGATION OF FACTORS AFFECTING PAINT FILM THICKNESS MEASUREMENTS. /AUTHOR/

• Supplemental Notes:
  • Vol 41, No 533, PP 372-382, 10 FIG, 12 TAB, 3 PHOT, 11 REF
• Authors:
  • Keane, J D
  • Wettach, W
  • Bosch, W
• Publication Date: 1969-6

Media Info

• Serial:
  • Journal of Paint Technology
  • Publisher: Federation of Societies for Paint Technology

Subject/Index Terms

• TRT Terms: Alkyd resins; Corrosion protection; Crash exposure; Films (Coatings); Hot rolling; Measurement; Paint; Service life; Steel; Testing; Thickness; Vinyl resins
• Uncontrolled Terms: Exposure; Film thickness
• Subject Areas: Design; Geotechnology; Highways; Materials; Safety and Human Factors;

Filing Info

• Accession Number: 00216421
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 4 1970 12:00AM