航空 发表于 2011-6-14 10:05:36

PRESSURE-SENSITIVE DECALS - REMOVAL/INSTALLATION

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航空 发表于 2011-6-14 10:06:52

<P>PRESSURE-SENSITIVE DECALS - REMOVAL/INSTALLATION<BR>1. General<BR>A. This procedure covers application and repair of pressure sensitive plastic film decals.<BR>B. Apply external sectionalized decal in such a sequence that the overlapping end is downstream<BR>from the line of flight.<BR>C. Activate pressure sensitive adhesives when applying decals at ambient temperatures below<BR>60°F.<BR>D. Clean plastic film decals with naphtha. Do not use adhesive activator.<BR>E. Air bubbles may be worked out any time within 8 hours after decal application. Puncture the<BR>decal film with a sharp pointed instrument, at the edge of the bubble, and press the air out<BR>through the punctured hole.<BR>F. Interior decals may also be installed using the same process as pressure-sensitive placards<BR>(Ref. 20-10-121).<BR>2. Equipment and Materials<BR>A. Solvents and Thinners (Ref. 20-30-31)<BR>(1) Aliphatic Naphtha - TT-N-95<BR>(2) Cleaning Solvent - BMS 3-2<BR>(3) Methyl Isobutyl Ketone - TT-M-268</P>
<P>(7) No. 2911 Thinner<BR>(8) Activator Solvents<BR>(a) A-2 Activator<BR>(b) Cyclohexanone<BR>(c) A-3 Activator<BR>B. Paints and Finishes (Ref. 20-60-4)<BR>(1) Enamel - BMS 10-11 Type 2<BR>(2) Vinyl-Type Paint - MIL-P-8793<BR>(3) Vinyl Process Pastes - 3900 Series<BR>(4) No. 2960 Edge Sealer<BR>(5) No. 700 Finishing Clear<BR>C. Miscellaneous<BR>(1) Masking Tape - UU-T-106 (Ref. 20-60-5)<BR>(2) Felt squeegee<BR>(3) Cheesecloth (Ref. 20-60-5)<BR>(4) Plastic scraper<BR>(5) Abrasive paper, 140 grit<BR>(6) Scotchcal Cutter - Boeing tool St 732<BR>3. Remove Decals<BR>A. Exterior decals are removed by paint stripping.</P>
<P>B. Interior decals, such as indicia strips on instrument panels, instructional decals, etc., installed<BR>on interior of airplane are removed by either heat softening or by solvent breakdown.<BR>(1) Remove interior decals by heat softening.<BR>(a) Heat decal to approximately 120°F until adhesive softens.<BR>CAUTION: OVERHEAT WILL CAUSE SOME DECALS TO MELT,<BR>NECESSITATING REMOVAL BY SOLVENT.<BR>(b) Lift corner of decal with sharp spatula or knife blade and peel decal from substrate.<BR>(c) If required, clean substrate using cheesecloth pad moistened with solution made of<BR>equal parts of cleaner and water.<BR>(2) Remove interior decals by solvent breakdown.<BR>(a) Wet decal with Aliphatic Naphtha using brush or cloth.<BR>(b) After decal is wrinkled (approximately 2 minutes after wetting), rewet surface again.<BR>(c) After approximately 2 minutes, slide softened decal off of substrate or scrape off<BR>using spatula.<BR>(d) If required, clean substrate using cheesecloth pad moistened with Aliphatic Naphtha.<BR>4. Install Decal<BR>A. Clean receiving surfaces.<BR>(1) Clean corroded aluminum surfaces per Chapter 51, Corrosion Removal and Control.<BR>(2) Clean wax-coated aluminum surfaces per Chapter 12, Cleaning and Washing, until area<BR>shows a water-break-free surface.<BR>(3) Clean unpainted polyester or phenolic plastics with Aliphatic Naphtha and a clean cloth.<BR>Wipe cleaner dry with a clean cloth. Do not allow to air-dry.</P>
<P>(4) Lightly sand cork surfaces with 150-grit abrasive paper until a clean cork surface is<BR>obtained. Remove sanding dust with a clean dry cloth.<BR>(5) Clean all other surfaces thoroughly with naphtha cleaner and a clean dry cloth. Do not<BR>allow cleaner to evaporate, but wipe dry with a clean cloth.<BR>B. Prepare decal for installation.<BR>(1) On decals with an area of less than 1 square foot, remove the backing and lay the decal<BR>face down on a smooth surface.<BR>(2) On decals with an area of greater than 1 square foot, position the decal on the receiving<BR>surface using masking tape.<BR>(a) Cut a sheet of carrier tape approximately 4 inches longer than the decal and about<BR>the same width. When using premasked decals, the premask may be used as a<BR>carrier.<BR>(b) Place the carrier over the decal, with the edge to be hinged 2 to 3 inches beyond the<BR>decal edge.<BR>(c) Hinge the carrier to the receiving surface with masking tape.<BR>(d) Wipe the carrier on with a plastic scraper. Using short strokes, work from the<BR>midpoint of the hinge to The edges, removing all wrinkles and air bubbles.<BR>(e) Fold the carrier and decal back at hinge, along the surface with the backing upward.<BR>Use masking tape to hold in this position.<BR>(f) Remove the decal backing.<BR>(3) On strip decals, remove about 1 foot of backing and lay the decal face down on a smooth<BR>surface.<BR>(4) Activate the adhesive surface of solvent activated decals with A-2 activator or<BR>cyclohexanone.<BR>NOTE: If ambient temperature is below 60F, use A-3 activator.<BR>(a) Dip a felt squeegee in activator solvent and blot excess solvent with an absorbent<BR>cloth.</P>
<P>(b) Draw the felt squeegee evenly across the adhesive side of the decal. Do not allow<BR>activator to touch film face.<BR>1) Activate strip decals for approximately 6 inches.<BR>2) Activate the entire surface of all other decals using overlapping strokes.<BR>WARNING: A-2 AND A-3 ACTIVATORS AND CYCLOHEXANONE ARE<BR>TOXIC AND FLAMMABLE. USE IN WELL VENTILATED AREAS<BR>AND AVOID PROLONGED INHALATION OF VAPORS.<BR>C. Apply decal to regular surface.<BR>(1) Position decals with areas less than 1 square foot and adhere one edge to surface. Hold<BR>remainder of decal taut and slightly away from receiving surface with a piece of backing on<BR>the adhesive side.<BR>(2) Swing the carrier of decals with an area greater than 1 square foot, into position holding<BR>the free end taut and slightly away from the receiving surface with a piece of backing on<BR>the adhesive.<BR>(3) Align and adhere about 3 inches of strip decals to the receiving surface.<BR>(a) Using the applied section as a hinge, strip up to 3 feet of the backing and, if<BR>necessary, activate the adhesive.<BR>(b) Align the stripping and hold it taut and slightly away from the receiving surface.<BR>(4) Starting at the hinge, rub the decal onto the surface using the plastic scraper with short<BR>fan-like strokes. Do not allow the adhesive to touch the receiving surface until the plastic<BR>scraper presses it down.<BR>(5) Continue stripping, activating and applying strip decals until all of the decal has been<BR>applied.<BR>(6) When applying strip decals around a corner and a splice occurs, overlap decal a minimum<BR>of 2 inches.</P>
<P>D. Apply decal over irregular surfaces.<BR>(1) Decals applied over a joint between two surfaces which move with respect to each other.<BR>(a) For gaps of 0.100 inch and greater, cut the decal at the approximate center of the<BR>gap and wrap the decal around both edges. See Method A, figure 201.<BR>(b) For gaps of less than 0.100 inch, cut the decal flush with the forward or upper skin<BR>edge and wrap the decal around the aft or lower skin edge. See Method B.<BR>(2) Decals applied across lap joints<BR>(a) The decal, when it is applied, is wrapped smoothly and continuously around the edge<BR>of the lap joint. See Method C (preferred method).<BR>(b) An alternate method, acceptable where the decal extends along the lap joint for a<BR>considerable distance, is to cut the decal flush with the overlap edge and butt the<BR>remainder of the decal with the overlap edge. See Method C.<BR>(3) Decals applied to exterior emergency exit handles. See Method E.<BR>(a) Before removing the backing paper, place the decal on the handle and slit the decal<BR>overlap around each rounded corner.<BR>(b) Remove the backing paper and apply the decal, pressing the overlap around the<BR>edges of the handle.<BR>(4) Using tool St 732, cut decals, except pressure sensitive Polyester, around the heads of<BR>fasteners on removable panels and punch the decal into the recessed slot. Cut and<BR>remove an area of film, of pressure sensitive polyester decals, the approximate size of a<BR>nonflush rivet or fastener using tool St 732. Press the decal film firmly in place around the<BR>rivet or fastener. Allow the adhesive to cure for 1/2 hour before sealing edges.<BR>(5) Puncture the decal film, with a sharp pointed instrument, at each rivet of decals applied<BR>over pressurized areas.</P>

bocome 发表于 2011-7-30 18:10:36

PRESSURE-SENSITIVE DECALS - REMOVAL/INSTALLATION
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