DeFelsko PosiTest AT-A Manual De Instrucciones página 2

The PosiTest AT-A Pull-Off Adhesion Tester measures the
force required to pull a specified test diameter of coating away
from its substrate using hydraulic pressure. The pressure is dis-
played on a digital LCD and represents the coating's strength of
adhesion to the substrate.
In accordance with ASTM D4541, D7234, ISO 4624, and
others, the PosiTest AT-A 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
Clean and abrade the dolly and coating (pg. 3)
2. Glue & Dolly Application
Prepare the glue, apply it to the dolly, and place the dolly on the
coated surface, allowing the glue to cure (pg. 4).
3. Test Area Isolation - optional
Isolate the test area of the coating from the area surrounding
the dolly by cutting or drilling (pg. 5).
4. Pull-Off Test (pg. 5).
5. Analysis of Test Results
Examine and evaluate the dolly and coating to determine the
nature of the coating failure (pg. 8).
Introduction
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