ASTM D1781 Test Fixture

ASTM D 1781 Drum Peel Test Fixture

Climbing Drum Peel, Mechanical Vice Action Grip

This test method covers the determination of the peel resistance of adhesive bonds between a relatively flexible adherend and a rigid adherend; and the relatively flexible facing of a sandwich structure and its core, when tested under specified conditions.

Peeling Apparatus, consisting of a flanged drum, flexible loading straps or cables, and suitable clamps for holding the test specimen.

The outside radius of the drum is 51.00 ± 0.13 mm, and the radius of flange, including one half of the thickness of the loading straps or cables, is 12.70 ± 0.13 mm larger than the radius of the drum. This 12.70 ± 0.13 mm less half the thickness of the adherend to be peeled, is the effective torque arm of the apparatus.

ASTM D 1781 Specimen Preparation
The specimen should be 25 mm (1 in.) wide between saw kerfs and at least 254 mm (10 in.) long.
Test must be made with least six specimens, for example, two or more from each of three bonded panels, for each adhesive sample.
For sandwich structures based on orthotropic cores, half of the samples should be peeled parallel to the length direction of the core and half parallel to the width direction, as determined from the configuration of the cell structure.

ASTM D 1781 Conditioning the Test Specimen
Condition specimens for 7 days at a relative humidity of 50 6 2 % and a temperature of 23 ± 1°C (73.4 ±1.8°F), except when the adhesive manufacturer specifies that this conditioning period is unnecessary and that a shorter period is adequate. The manufacturer may also specify that a longer period is necessary.

ASTM D 1781 Testing Procedure | Adhesives | Peel Testing
1. The climbing drum peel fixture with sample should be mounted in the test frame.
2. Apply a tensile load at a constant rate of crosshead separation and determine the average peeling load between 1in and 6in of adherend separation. The corresponding amount of crosshead movement is dependent on the geometry of the climbing drum peel fixture.
3. Determine the peel resistance over at least 152 mm (6 in.) of the bond by loading the apparatus in tension at a crosshead speed of 25.40 ± 2.54 mm/min (1.00 ± 0.10 in./min).
4. Calculate and report the average peel torque. To ensure compliance, please read the entire ASTM D1781 test specification prior to testing.

Calculations:
• Average Peeling Load
• Average Peel Torque