SD3-60 STRUCTURAL REPAIR MANUAL OF HEAT RESISTANT PAINT AND PROTECTIVE COATINGS

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Percival Goodman
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1 SD3-60 STRUCTURAL REPAIR MANUAL z SRM APPLICATION OF HEAT RESISTANT PAINT AND PROTECTIVE COATINGS 1. Introduction Refer to Figure 1. This subject defines the requirements and procedures for the preparation and painting of SD3.60 aircraft wingskin and flap areas, which are impinged by engine exhaust emmisions. These areas are defined in Figure 1. The system comprises of the application of a heat resisting paint, complemented by the addition of a temporary protective coating, which can be removed and reapplied when necessary ie when the appearance becomes impaired due to soiling. This subject is generally as Bombardier Aerospace (Belfast) Specifications WPI 50 & WPI 51). 2. Equipment and Materials Refer to , pb1. A. The equipment required for paint mixing; paint spraying; paint film measurement; cleaning materials; and miscellaneous materials, are as referred (para 4.A, 4.B, 4.E and 4.F respectively. Page 1

2 z SD3-60 STRUCTURAL REPAIR MANUAL B. Primers and Paints (1) (a) Koroflex Primer to MIL-P Base Koroflex primer (one pack) (b) Flexible Polyurethane Finish (Black) to AFS 1605 Base FE 102 Activator 102 Thinners T1/5 (TH193) (2) (a) Temporary Protective Coating Cee-Bee A-6 (b) Temporary Protective Remover Cee-Bee A-276 (See Note (1)) Supplier: Desoto Titanine PLC, Shildon, Co. Durham, England (See note (1)) Supplier: Brimpex Metal Treatments 5 Devonshire Close Dore, Sheffield England, S17 3NX (See note (2)) NOTE: (1) Earlier aircraft were painted with Desoto Titanine TT30 Heat Resistant Paint (using TT 142 Thinners). At the operators discretion this paint system may be repaired as necessary. Alternatively, it may be removed completely, together with the existing epoxy primer, (in accordance with the procedures described in CHAP/SECT ), and replaced by the Flexible Polyurethane Finish noted at Para 2 (a) above. In either case, the Temporary Protective Coating is recommended, (to provide improved erosion and corrosion resistance), prior to any engine trials. (2) Alternative suppliers: Dinol International AB, Box 149 S28101 Hasselholm, Sweden or: Dinol International Inc Hamilton Avenue Michigan 48203, USA or any other approved supplier. Page 2

3 SD3-60 STRUCTURAL REPAIR MANUAL z Areas of Application for Heat Resistant Paint and Protective Coating Figure 1 Page 3

4 z SD3-60 STRUCTURAL REPAIR MANUAL 3. Safety Precautions Refer to , pb1. The safety precautions described (para 5.) are to be implemented at all times. 4. Environmental Conditions A. Refer to , pb1. The temperature and humidity (para 3.). B. Environmental Conditioning of Aircraft Structure prior to Painting When final painting of the aircraft is to take place, at least 24 hours should be allowed for the aircraft structure temperature to reach that of the surrounding area before commencing painting. The maximum difference between the structure and the surrounding area temperature is to be 2 C. 5. Storage and Re-life A. The paint materials shall be usable for a period of 12 months from the date of receipt when stored at a temperature of 4 to 30 C. B. The protective coating shall be usable for a period of 24 months from the date of receipt when stored at a temperature of 4 to 30 C. Materials which have exceeded the above storage time may be re-lifed at the discretion of the Local Controlling Laboratory. 6. Procedures A. Painting The aircraft must be sited to take the fullest advantage of the paint shop extraction system, and must be sprayed so as to minimize the spray fallout on freshly sprayed areas. B. General (1) The procedures detailed in this subject must be applied in a single sequence. No single operation may be omitted. (2) areas which do not require application of the paint system and/or protective coating, shall be protected as follows:- (a) Construct, using Brown Kraft paper, a mask of the required shape and size. (b) Secure mask over the specified area with Pressure Sensitive Adhesive Paper Tape. (c) For small areas, masking tape only may be used. Page 4

5 SD3-60 STRUCTURAL REPAIR MANUAL z C. Surface Preparation (1) Painting The existing paint scheme is to be stripped from the appropriate wing skin areas. Refer to , pb1. (see also Note (1) at Paragraph 2). Areas affected by corrosion are to be repaired in accordance with the relevant repair drawing. Refer to , pb201. Alocrom any bare or anodised metal surface, (not coated with BSL 101), including the corrosion affected areas, with Alodine/Alocrom Refer to , pb1. (2) Protective Coating D. Painting (a) Wingskin and flap areas to which the protective coating is to be applied shall have been primed and finish coated in accordance with Paragraph 6 (D). (b) Solvent clean the complete surface to be coated using TDL or CN 45 (AFS 1826) cleaning fluid. ow surface to fully dry. The paint system is as follows:- - Prime with Koroflex Primer - Topcoat with FE 102 Polyurethane Finish (Black). NOTE: Prior to painting, mask all areas not requiring painting in accordance with paragraph 6 B (2) (1) Application of Koroflex Primer (a) It is essential to shake and stir Koroflex primer using a mechanical stirrer sufficiently to provide a homogenous medium. (b) Viscosity of the primer is 18 to 28 seconds using a Zahn 2 cup. If required, the primer may be thinned using MEK. (c) Koroflex primer should be applied to the Alocromed surface within 1 to 5 hours to application of the Alodine/Alocrom. (d) Apply one track coat of Koroflex to give a dry film thickness of 38 ± 8 microns. If a second coat of Koroflex is required, allow one hour between coats. Page 5

6 z SD3-60 STRUCTURAL REPAIR MANUAL (e) Drying time shall be chosen in accordance with the, 'Time to Topcoat' guide. Refer to Figure 2. NOTE: The length of time for drying before topcoating, depends on temperature and relative humidity conditions during application and cure. The drying times will vary as the temperature and humidity fluctuates. (2) Application of FE 102 Finish (a) Mix, apply and dry FE 102. Refer to , pb1. (b) Examine for appearance and check for adhesion in accordance with Paragraph 8. (c) Dry film thickness of the finish coat should be 30 to 40 microns. NOTE: (1) Other polyurethane topcoats may be used in lieu of FE 102, but only with the approval of Bombardier Aerospace, Materials Technology and Design Departments. (2) Following application of the Flexible Paint System, and prior to any engine trials, Protective Coating Cee-Bee A-6 shall be applied in accordance with Paragraph 6 E. E. Application of Cee-Bee A-6 Protective Coating (1) Stir the protective coating thoroughly to ensure a uniform mix. (2) Apply by spraying a single cross coat of protective coating. NOTE: The coating may be applied by brush if spray equipment is not available. (3) ow to dry for 15 to 35 minutes. F. Removal of Cee-Bee A-6 Protective Coating The coating can be removed when required, ie when the appearance becomes impaired due to soiling, by using A-276 remover as follows:- (1) Stir the A-276 Remover thoroughly to ensure a uniform mix. (2) Apply the remover by brush. ow to dwell for approximately 5 minutes until it penetrates and softens the protective coating. If required, agitate lightly by brush. Thoroughly flush the loosened protective coating from the surface with a flowing water rinse. (3) Reapply the Cee-Bee A-6 coating, if necessary, in accordance with Paragraphs 6 C (2) and 6 Refer to E.. Page 6

7 SD3-60 STRUCTURAL REPAIR MANUAL z Time to Topcoat Guide Figure 2 Page 7

8 z SD3-60 STRUCTURAL REPAIR MANUAL 7. Quality Requirements A. General (1) The Quality Department shall be satisfied that the requirements of this subject have been complied with, paying particular attention to those requirements specified in paragraph 4. (2) The Quality Department shall verify that:- (a) The materials have been released to the relevant requirements. (b) Refer to , pb1. Operations performed prior to priming (also refer to paragraph 6 of this subject) have been correctly selected and applied, and interoperational times have been adhered to. B. Appearance, Adhesion and Thickness Refer to , pb1. The Quality Department shall verify that the appearance, adhesion and thickness comply with the requirements (para 11). Page 8

SD3-60 STRUCTURAL REPAIR MANUAL OF AIRCRAFT AND COMPONENTS

SD3-60 STRUCTURAL REPAIR MANUAL OF AIRCRAFT AND COMPONENTS SRM 9.0.0.0PAINTING OF AIRCRAFT AND COMPONENTS 1. Introduction This section outlines the various procedures and equipment used for the removal of paint, preparation, priming, painting, and the application