Structural Adhesive Film

AF 555

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B. Aluminum Honeycomb Core

D. Stainless Steel – Type 301

1. Soak in clean aliphatic naphtha (conforming to TT-N-95A) for five minutes

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

2. Optional – Immerse in etching solution above for 2 minutes 155 ± 5°F.

Rinse, air dry and force dry in a similar manner to skins.

processing have been used successfully with 3M™ Scotch-Weld™ Structural

Adhesive Film AF 555.

1. Vapor hone 140 grit in water – rinse thoroughly with clear running tap water.

2. Degrease – solvent or alkaline process.

3. Immerse for 15 minutes at 185 ± 5°F in the following bath:

Distilled water – Balance to make 1 liter

4. Immerse for 1 minute in 170 ± 5°F distilled water.

5. Spray rinse for 5 minutes in hot tap water ~ 130°F.

6. Air dry for 10 to 20 minutes.

7. Force dry for 15 minutes at 140°F (maximum).

8. It is advisable to bond or prime freshly cleaned surfaces within four hours.

*Available from Henkel North America.

1. Vapor hone 140 grit in water.

2. Rinse thoroughly in clear running tap water.

3. Alkaline degrease – see procedure above.

4. Rinse thoroughly in clear running tap water.

5. Immerse for 10 minutes at 75 ± 5°F in the following bath:

Distilled Water 73-95 oz/gal

Nitric Acid 42° Be 30-50 oz/gal

Hydrofluoric Acid 70% 3-5 oz/gal

6. Rinse thoroughly in clear running tap water.

7. Air dry for 10-20 minutes.

8. Force dry for 15 minutes at 150°F.

9. Bond or prime within four hours after preparing.

E. Cured fiberglass or carbon fiber reinforced epoxy resin based reinforced

plastic.

1. Abrade with 180 grit paper or 3M™ Scotch-Brite™ Scour Pad (do not

cut through resin into reinforcing fibers).

2. Degrease using acetone or using an unsized cheesecloth pad.

3. Air dry for two hours minimum.

XVI. Continued – Surface Preparation

Structural Adhesive Film

AF 555

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XVII. Primers

For most applications, use of a corrosion inhibiting primer is suggested to

obtain maximum bond durability in moist, corrosive environments. 3M™

Scotch-Weld™ Structural Adhesive Primers EW-5000, EW-5000AS, and

EC-3917 have all been successfully used with 3M™ Scotch-Weld™ Structural

Adhesive Film AF 555. Because of its characteristics which allow both spray

and brush application methods, either Scotch-Weld EW-5000 or EW-5000AS

are normally suggested for use with Scotch-Weld AF 555 films. For suggested

application techniques, refer to the respective primer data sheets.

Primer Coverage

For the primers noted above, the optimum mechanical property test performance

with Scotch-Weld AF 555 Film will normally be found with uniform primer coverage

by an Isometer*. As the primer weight is increased a gradual decrease in low

temperature peel strength will be found along with increasing levels of cohesive

fracture in the primer layer (exception: properly controlled 180° T-Peel

does not normally show this effect). Where specific tests and required strength levels

are involved, a few simple experiments with varied primer coverage will be required

to establish an allowable primer coverage range. Further applications can then be

controlled by correlating color or thickness standards for the acceptable range.

*Isometer from Forster Instruments, Ontario, Canada.

XVIII. Adhesive Film Application

Care should be taken during application to avoid contamination of the adhesive

and substrates by any substances which will interfere with the wetting action of

the adhesive.

Layup:

A. Scotch-Weld AF 555 U, M, or K Films

The following cycle is suggested for these primers when used with Scotch-Weld

AF 555 films:

EW5000 & EW5000 AS

EC-3917:

Cured Thickness

0.10-0.28 mils

0.10-0.20 mils

Air Dry

30 minutes

60 minutes

Force Dry

180 ± 5ºF for 30 ± 5 minutes

250 ± 5ºF for 60 ± 5 minutes

1. Cut a portion of film sufficient for the assembly from the stock roll with

protective liner(s) in place.

2. If the film has one protective liner, place the exposed adhesive against the

substrate using the liner as a protective cover. If two liners are present, remove

one and follow as above.

3. Position film and rub out all air between the adhesive and the substrate. Use of

a rubber roller will facilitate this process.

4. Remove protective liner.

5. Complete assembly being careful to avoid trapping air and cure.