Photograph shows two indenters to illustrate top and underside view,
only one indenter is supplied.

This instrument is used for an indentation test on a single or multicoat paint system. An indenter of specified size, shape and weight is applied to the coating under defined conditions.

The length of indentation produced is then compared to an evaluation table which gives the relationship between indentation length and indentation resistance. The table also shows depth of indentation in microns and the minimum coating thickness for which the measurement is valid.

This test method is less suitable for highly elastic coatings because the indentation will disappear soon after the instrument is removed from the surface.

1. A rectangular metal block of 1000 ±5gms mass fitted with a spirit level, two pointed feet and a circular indenter manufactured from hardened tool steel. The effective load on the indenter is 500 - 505 grams.
   
   
2. An illuminated microscope with 20x magnification. Light is projected onto the surface under inspection at an angle of incidence greater than 60°, a graduated scale in increments of 0.1mm is built into the microscope to allow direct measurement through the lens.
   
   
3. Plastic template to locate position of indentation when indenter is removed from the test panel.
   
   
4. A plastic, fitted carrying case.

• The indenter is carefully placed vertically onto the coated test panel and removed after 30 seconds.
  
  
• Carefully remove the template prior to measuring the indentation length.
  
  
• The apex of the triangle will locate the indentation when viewing through the microscope lens.
  
  
• When the indenter has been removed, the template triangle is positioned by placing the two spots over the marks left by the feet on the test sample.

Results are expressed as Buchholz indentation resistance, this can be calculated from the formula: