DeFelsko PosiTest AT-M Mode D'emploi page 2

The PosiTest AT-M Pull-Off Adhesion Tester measures the
force required to pull a specified test diameter of coating away
from its substrate using hydraulic pressure. Pressure is calculated
based on force and test area and represents the coating's
strength of adhesion to the substrate.
In accordance with ASTM D4541, D7234, ISO 4624, and
others, the PosiTest AT-M evaluates the adhesion (pull-off
strength) of a coating by determining the greatest tensile pull-off
force that it can bear before detaching. Breaking points,
demonstrated by fractured surfaces, occur along the weakest
plane within the system consisting of the dolly (loading fixture,
stub), glue, coating layers, and substrate.
Basic Steps to Perform a Pull-Off Test
1. Dolly & Coating Preparation
The dolly and the coating are cleaned and abraded (see below).
2. Glue & Dolly Application
The glue is prepared and applied to the dolly. The dolly is
then adhered to the coated surface and the glue is allowed to
cure (see pg. 2).
3. Test Area Isolation - optional
The test area of the coating is isolated from the area
surrounding the dolly by cutting or drilling (see pg. 3).
4. Pull-Off Test
5. Analysis of Test Results
The dolly and the coating are examined and evaluated to
determine the nature of the coating failure (see pg. 6).
Dolly Preparation
1. To remove oxidation and contaminants, place the included
abrasive pad on a flat surface and rub the base of the dolly
across the pad 4-5 times.
2. As required, remove residue left from the abrading process
using a dry cloth or paper towel.
Introduction
Dolly & Coating Preparation
1