Structural Adhesive Film

AF 31

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C. Suggested Surface Preparation for Titanium

1. Use Scotch-Brite™ Hand Pad to remove all lettering.

2. Clean in Oakite 164 for 10 minutes at 190°F (88°C). Water break necessary.

3. Etch in acid solution for 5 to 7 minutes at 120-135°F (49-57°C).

Acid make-up (to make approximately one gallon)

Distilled Water

2.36 Liters

1.29 Liters

HF (48%)

.13 Liters

4. Rinse in distilled water.

5. Soak in Phosphate-fluoride bath for 60-90 seconds at 90°F (32°C).

Bath make-up (to make approximately one gallon)

162 grams

Potassium Fluoride

41.7 grams

Hydrofluoric Acid (48%)

0.113 liters

Distilled Water

3.57 liters

6. Rinse in distilled water at 180°F (82°C) for 15 minutes. Rinse three times in

solution.

7. Rinse in distilled water.

8. Air dry at 190°F (88°C) for 20 minutes.

2. Adhesive Layup

A. Primer Application

1. Advantages

Priming of bonding surfaces offers two distinct advantages: (1) ensures complete

wetting of metal surfaces, which normally results in superior environmental

properties and (2) simplifies production by protecting cleaned parts until

bonding can be completed. 3M™ Scotch-Weld™ Structural Adhesive Primer

EC-2174 is recommended to use with 3M™ Scotch-Weld™ Structural Adhesive

Film AF 31.

2. Application

Scotch-Weld EC-2174 primer may be applied by brushing or flow coating using

one or two coats. A camel hair, horsehair or similar type brush is recommended.

Dried primer thickness should be 0.0002-0.0006 inches.

3. Primer Dry

a. Air dry for 60 minutes minimum at 75°F ± 5°F (24°C ± 2°C).

b. Force dry in an air circulating oven for 60 minutes at 265°F (129°C).

B. Film Application

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

2. Place film on metal using a separating liner as a protective cover.

3. Roll film into position with a rubber roller, ensuring that no air is trapped

between primer and film.

4. Remove protective liner.

5. Assemble parts and cure.

Excess primer and equipment may be cleaned prior to curing, with ketone*

type solvent.

*Note: When using solvents, extinguish all ignition sources and follow

manufacturer’s precautions and directions for use.

Product Application

(continued)