Structural Core Splice Adhesives

AF 3028 • AF 3028 FR

- 4 -

Product Performance

(continued)

7. Flexural Shear Strength:

Flexural shear strength of AF 3028 was determined by using a 3" x 8" beam flexure

specimen with a splice made with AF 3028 located 2" from one end of the flexure

specimen as shown below:

Adherends: 2024T-3 alclad aluminum, .063" thick.

Surface Preparation: FPL etch.

Honeycomb Core: 8.1, 1/8" cell-1/2" thick – 5052 alloy – 2 mil foil – nonperforated.

Core Splice: 2" in from one end of specimen. Spliced with one layer of AF 3028.

Cure Cycle: 250°F (121°C) for 60 minutes, 40 psi pressure (rise rate shown below).

Test: 3" x 8" specimens tested for flexural shear strength using double point loading at

.02"/minute. (Reference ASTM C-393).

Test Procedure:

Core shear strength determined according to ASTM-C-393 using the following conditions:

Load Pad: Double point loading.

Load Rate: 0.02"/minute.

Span: 6 inches.

Core Shear =

P

Where: P = Load at failure

t = specimens thickness

(psi)

Test Results:

Flexural Shear

Test Temperature

1-2°F rise rate/minute

7-8°F rise rate/minute

psi

MPa

psi

MPa

75°F (24°C)

815

(5.6)

857

(5.9)

220°F (104°C)

580

(4.0)

536

(3.7)

8. Flammability

A 0.120" thick by 1" wide cured specimen of AF 3028 FR was held in a vertical

position for 15 seconds, 3/4" above a burner which had a 1.5 inch high flame

(3M AdhD Test Method C-519). The flame in the specimen extinguished in an

average of 4 seconds upon removal of the burner.