PosiTest CH

ISO 2409

* For soft substrates (e.g. wood and plaster), use 2 mm / 6 Teeth for coating thicknesses between 0 – 120 μm (0 – 4.7 mils)

ASTM D3359

• PosiTest CH Leaflet

What is the maximum coating thickness the $\text{PosiTest CH}$ can test?

The PosiTest $\text{CH}$ can be used on coatings up to $\text{250 }\mu \text{m}$ ($\text{10 mils}$). The specific blade spacing (e.g., $\text{1 mm, 2 mm, 3 mm}$) must be selected based on the coating thickness and the standard being followed ($\text{ISO}$ or $\text{ASTM}$).

Does the PosiTest $\text{CH}$ measure absolute adhesion strength in $\text{psi}$ or $\text{MPa}$?

No, the PosiTest $\text{CH}$ is a qualitative adhesion tester. It determines coating adhesion by classification (e.g., $\text{5B, 5, 4B, 4, etc.}$) based on the visual appearance of the grid cut after tape removal, not by a quantitative tensile pull-off force.

What is the purpose of the pivoting cutting head?

The pivoting head is essential for maintaining constant contact pressure and angle between the cutting blade and the coated surface. This ensures that the lattice pattern is cut to the substrate correctly and consistently, which is crucial for achieving a reliable, non-subjective test result.

Are the $\text{ISO}$ and $\text{ASTM}$ adhesive tapes the same?

No, the adhesive tape specifications for $\text{ISO 2409}$ and $\text{ASTM D3359}$ are different, particularly in their adhesion values. The PosiTest $\text{CH}$ kits come with the correct, certified tape that conforms to the specified standard.

How often should the cutting blades be replaced?

The high-grade hardened steel blades have four usable cutting edges. They should be replaced when the quality of the cut deteriorates or when all four edges have been used, ensuring a clean cut that reaches the substrate for accurate adhesion testing.