STANDARD PRACTICES

民航

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民航

1. General A. This procedure covers application and repair of pressure sensitive plastic film decals. B. Apply external sectionalized decal in such a sequence that the overlapping end is downstream from the line of flight. C. Activate pressure sensitive adhesives when applying decals at ambient temperatures below 60°F. D. Clean plastic film decals with naphtha. Do not use adhesive activator. E. Air bubbles may be worked out any time within 8 hours after decal application. Puncture the decal film with a sharp pointed instrument, at the edge of the bubble, and press the air out through the punctured hole. F. Interior decals may also be installed using the same process as pressure-sensitive placards (Ref. 20-10-121). 2. Equipment and Materials A. Solvents and Thinners (Ref. 20-30-31) (1) Aliphatic Naphtha - TT-N-95 (2) Cleaning Solvent - BMS 3-2 (3) Methyl Isobutyl Ketone - TT-M-268 (7) No. 2911 Thinner (8) Activator Solvents (a) A-2 Activator (b) Cyclohexanone (c) A-3 Activator B. Paints and Finishes (Ref. 20-60-4) (1) Enamel - BMS 10-11 Type 2 (2) Vinyl-Type Paint - MIL-P-8793 (3) Vinyl Process Pastes - 3900 Series (4) No. 2960 Edge Sealer (5) No. 700 Finishing Clear C. Miscellaneous (1) Masking Tape - UU-T-106 (Ref. 20-60-5) (2) Felt squeegee (3) Cheesecloth (Ref. 20-60-5) (4) Plastic scraper (5) Abrasive paper, 140 grit (6) Scotchcal Cutter - Boeing tool St 732 3. Remove Decals A. Exterior decals are removed by paint stripping. B. Interior decals, such as indicia strips on instrument panels, instructional decals, etc., installed on interior of airplane are removed by either heat softening or by solvent breakdown. (1) Remove interior decals by heat softening. (a) Heat decal to approximately 120°F until adhesive softens. CAUTION: OVERHEAT WILL CAUSE SOME DECALS TO MELT, NECESSITATING REMOVAL BY SOLVENT. (b) Lift corner of decal with sharp spatula or knife blade and peel decal from substrate. (c) If required, clean substrate using cheesecloth pad moistened with solution made of equal parts of cleaner and water. (2) Remove interior decals by solvent breakdown. (a) Wet decal with Aliphatic Naphtha using brush or cloth. (b) After decal is wrinkled (approximately 2 minutes after wetting), rewet surface again. (c) After approximately 2 minutes, slide softened decal off of substrate or scrape off using spatula. (d) If required, clean substrate using cheesecloth pad moistened with Aliphatic Naphtha. 4. Install Decal A. Clean receiving surfaces. (1) Clean corroded aluminum surfaces per Chapter 51, Corrosion Removal and Control. (2) Clean wax-coated aluminum surfaces per Chapter 12, Cleaning and Washing, until area shows a water-break-free surface. (3) Clean unpainted polyester or phenolic plastics with Aliphatic Naphtha and a clean cloth. Wipe cleaner dry with a clean cloth. Do not allow to air-dry. (4) Lightly sand cork surfaces with 150-grit abrasive paper until a clean cork surface is obtained. Remove sanding dust with a clean dry cloth. (5) Clean all other surfaces thoroughly with naphtha cleaner and a clean dry cloth. Do not allow cleaner to evaporate, but wipe dry with a clean cloth. B. Prepare decal for installation. (1) On decals with an area of less than 1 square foot, remove the backing and lay the decal face down on a smooth surface. (2) On decals with an area of greater than 1 square foot, position the decal on the receiving surface using masking tape. (a) Cut a sheet of carrier tape approximately 4 inches longer than the decal and about the same width. When using premasked decals, the premask may be used as a carrier. (b) Place the carrier over the decal, with the edge to be hinged 2 to 3 inches beyond the decal edge. (c) Hinge the carrier to the receiving surface with masking tape. (d) Wipe the carrier on with a plastic scraper. Using short strokes, work from the midpoint of the hinge to The edges, removing all wrinkles and air bubbles. (e) Fold the carrier and decal back at hinge, along the surface with the backing upward. Use masking tape to hold in this position. (f) Remove the decal backing. (3) On strip decals, remove about 1 foot of backing and lay the decal face down on a smooth surface. (4) Activate the adhesive surface of solvent activated decals with A-2 activator or cyclohexanone. NOTE: If ambient temperature is below 60
F, use A-3 activator. (a) Dip a felt squeegee in activator solvent and blot excess solvent with an absorbent cloth (b) Draw the felt squeegee evenly across the adhesive side of the decal. Do not allow activator to touch film face. 1) Activate strip decals for approximately 6 inches. 2) Activate the entire surface of all other decals using overlapping strokes. WARNING: A-2 AND A-3 ACTIVATORS AND CYCLOHEXANONE ARE TOXIC AND FLAMMABLE. USE IN WELL VENTILATED AREAS AND AVOID PROLONGED INHALATION OF VAPORS. C. Apply decal to regular surface. (1) Position decals with areas less than 1 square foot and adhere one edge to surface. Hold remainder of decal taut and slightly away from receiving surface with a piece of backing on the adhesive side. (2) Swing the carrier of decals with an area greater than 1 square foot, into position holding the free end taut and slightly away from the receiving surface with a piece of backing on the adhesive. (3) Align and adhere about 3 inches of strip decals to the receiving surface. (a) Using the applied section as a hinge, strip up to 3 feet of the backing and, if necessary, activate the adhesive. (b) Align the stripping and hold it taut and slightly away from the receiving surface. (4) Starting at the hinge, rub the decal onto the surface using the plastic scraper with short fan-like strokes. Do not allow the adhesive to touch the receiving surface until the plastic scraper presses it down. (5) Continue stripping, activating and applying strip decals until all of the decal has been applied. (6) When applying strip decals around a corner and a splice occurs, overlap decal a minimum of 2 inches

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STANDARD PRACTICES

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