Structural Core Splice Adhesives

AF 3028 • AF 3028 FR

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Product Application

The product performance data were developed using the following suggested procedures.

1. Surface Preparation:

A thoroughly cleaned, dry, grease-free surface is recommended for maximum

performance. Cleaning methods which will produce a breakfree water film on

metal surfaces generally satisfactory.

A. Aluminum Skins and Tubes (3M Test Method C-2803 or ASTM D 2651)

1. Alkaline Degrease – Immerse skins in Oakite 164 solution (9-11 oz./gallon

water) at 190 ± 10°F (82 to 93°C) for 15 ± 5 minutes. Rinse in generous

quantities of clear running distilled, deionized, or tap water.

2. Optimized FPL Etch Solution (1 liter)

Material

Amount

Distilled Water

700 ml plus balance of liter (see below)

Sodium Dichromate

28 to 67.3 grams

Sulfuric Acid

287.9 to 310.0 grams

Aluminum Chips

1.5 grams/liter of mixed solution

To prepare 1 liter of this solution, dissolve sodium dichromate in 700 ml of

distilled water. Add sulfuric acid and mix well. Add additional distilled

water to fill 1 liter. Heat mixed solution to 150 to 160°F (66 to 71°C).

Dissolve 1.5 grams of 2024 bare aluminum chips per liter of mixed solution.

Gentle agitation will help aluminum dissolve in about 24 hours.

To FPL etch panels, place them in the above solution at 150 to 160°F (66 to

71°C) for 12 to 15 minutes.

Note: Review and follow safety and precautionary information provided by

chemical supplier prior to preparation of this etch solution.

3. Rinse – Rinse face sheets in clear running tap water.

4. Dry – Air dry 15 minutes; force dry 10 minutes minimum at 140°F (60°C)

maximum.

B. Aluminum Honeycomb Core

1. Soak in clean aliphatic naptha* (to conform to TT-N-95A) for five minutes

at room temperature. Dry 10 minutes at 140°F (60°C) maximum.

2. Optional – Immerse in acid etching solution above in A. for (2) minutes at

155 ± 5°F (66 to 71°C). Rinse, air dry and force dry in similar manner to

skin panels.

*When using solvents, extinguish all ignition sources and follow manufacturer’s

precautions and directions for use.

2. Film:

Care should be taken to avoid contaminating adhesive and cleaned or primed

aluminum by any substance which will hinder wetting action of the adhesive.

A. Film Application

1. Cut portion of film to be used from roll with protective liners in place.

2. Remove liner from one side of the film.

3. Place film on metal or edge or honeycomb core using the remaining liner as

a protective cover.

4. On metal surfaces, roll film into position with a rubber roller to insure that

no air is trapped between film and metal.

5. Remove second protective liner.

6. Assemble parts and cure.