DeFelsko PosiTest AT v.4.0 - Manual (Page 2)

Introduction Introduction
The portable, hand-operated PosiTest 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 displayed on a digital LCD and repre-
sents the coating's strength of adhesion to the substrate.
In accordance with ASTM D4541, D7234, ISO 4624 and others, the PosiTest
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, adhesive, coating layers and substrate.
Basic steps for testing coating adhesion with a PosiTest Adhesion Tester:
1. Dolly & Coating Preparation
The dolly and the coating are cleaned and abraded. (see pg. 4)
2. Adhesive & Dolly Application
The adhesive is prepared and applied to the dolly. The dolly is then adhered
to the coated surface and the adhesive is allowed to cure. (see pg.4)
3. Test Area Separation - Optional step
The test area of the coating is separated from the area surrounding the
dolly by cutting or drilling. (see pg. 5)
4. Pull-off Test
a) PosiTest AT-M (manual) (see pg. 6)
b) PosiTest AT-A (automatic) (see pg. 8)
5. Analysis of Test Results
The dolly and the coating are examined and evaluated to determine the
nature of the coating failure. (see pg. 10)
6. Store Pull-Off Test Results - Optional step
The PosiTest’s internal memory stores maximum pull pressure, pull rate,
test duration and dolly size for up to 200 pulls. (see pg. 10)
Throughout this manual, the symbol indicates more information
about the particular topic or feature is available on our website.
Go to: www.defelsko.com/manuals
NOTE:
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