1、MIL-C-237bOD PA U 9999906 0283288 9 = Mil-C-23760D 4 October 19C3 Superseding Mil-C-23760C 21 September 1977 MILITARY SPECIFICATION COATING, SPRAYABLE, STRIPPABLE, PROTECTIVE, FOR PACKAGING OF WEAPONS SYSTEMS AND COMPONENTS: APPLICATION OF This s-pecification is approved for use by all Departments a
2、nd Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers the detailed requirements and pro=es to be followed in the application of spray- able, strippable coatings approved under MIL-C-6799 for the protection of painted and unpainted, metallic or plastic surfaces for w
3、eapon systems and components. The details contained herein shall not be construed as modifying any requirements of the basic material specifications. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1 .I Specifications, standards, and handbooks. Unless otherwise specified, the following specifica
4、tions, standards, and handbooks of the issue listed in that issue of the Department of Defense Index of Specifications and Standards (DoDISS) specified in the solicitation form a part of this specification to the extent specified herein. SPEC IF ICAT IONS FEDERAL P-P-560 Polish, Plastic P-W-155 Wax,
5、 Floor, Water Emulsion. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commanding Officer, Engineering Specifications and Standards Department (Code 93), Naval Air Engineering Center, Lakehrst,
6、 NJ 08733, by using the self -addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. NO DELIVERABLE DATA REQUIRED BY TH IS DOCUMENT AREA PACK Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
7、IHS-,-,- - - MIL-C-237bOD PA W 777790b 0283287 O MIL-C-23760D SPECIFICATIONS (Continued) FEDERAL (Continued) QQ-A-1876 ccc-c-440 PPP-F-320 MIL ITARY MIL-B-121 MI L-B- 1 31 MI L-C-6799 M I L-S - 1 5 847 Aluminum Foi 1 Cloth, Cheesecloth, Cotton, Bleached and Unbleached Fi berboard, Corrugated and Sol
8、id, Sheet Stock (Container Grade), and Cut Shapes Barri er Materi al, Greaseproofed, Waterproofed, Flexible Barrier Materi als, Watervaporproof, Flexible, Heat -seal able Coating, Sprayable, Strippable, Protective, Water Emu 1 s i on Spray Guns and Accessories, Paint and Dope, Aircraft Use MIL-T-215
9、95 MI L-T-22085 STANDARDS FEDERAL FE 0-STD- 5 95 MIL I TARY MIL-STD-129 MS33739 Tape, Pressure Sensitive Adhesive, Masking, Non Staining, For Aircraft Painting Applications Tape, Adhesive, Preservation and Sealing Color (Requirements For Individual Color Chips) Marking for Shipment and Storage Aircr
10、aft Markings, Servici ng and Precautioni ng (Copies of documents required by contractors in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting officer. ) 2.2 Order of precedence. In the event of a conflict between the tex
11、t of this specification and the references cited herein, the text of this specification shall take precedence. 3. REQUIREMENTS 3.1 Facilities for application. Application of sprayable, strippable compounds as listed herein shall normally be performed in any standard paint area. These compounds may a
12、lso be applied outdoors in an 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. I MIL-C-237bD PA m 997990b 0283290 7 m MIL-C-23760D area protected from dust, wind, and rain provided the temperature is between 45“ and 125OF. When the temperature is
13、below the specified range, temporary enclosures utilizing hot air heaters or ducts to pipe in heat shall be utilized. When ambient temperatures are above 100OF and relative humidity is below 30 percent, strippable coatings will usually be of poor quality (dry, porous, and non-strippable) when sprayi
14、ng is done in direct sunlight. these problems exist, areas to be sprayed should be provided with temporary shade to reduce surface temperatures while coatings are being applied. If I 3.1.1 . Personnel safety requirements. Al 1 requisite safety precautions shall be taken by personnel under the superv
15、ision of the Safety Engineer and the Industrial Health Officer. 3.2 Equipment. 3.2.1 Spray Equipment. To obtain best results, it is recommended that airless spray equipment be used such as the Grayco Bulldog Model #205-591 gun with standard tip. A reverse-A-clean tip with an orifice between 0.017 an
16、d 0.021 inch with a spray angle between 40 degrees to 60 degrees is recommended. In the absence of an airless unit, a DeVilbiss MBC model with an FF fluid tip and No. 765 air cap or equivalent may be used. Binks Model 18 Spray Gun, Fluid Nozzle 636, Aircap 63P8, and Fluid Needle 63A are also conside
17、red adequate alternatives. Accessories such as pressure tanks, agitator, hoses, oi 1 and water separator, gauges, and regulators shall conform to MIL-S-15847. All lines shall be kept free from condensation by blowing out the lines as necessary. Spray equipment parts in contact with the strippable co
18、ating material should be manufactured of stainless steel or other corrosion resistant materi al. 3.2-2 Care of spray equipment. 3.2.2.1 Continuous operation. At the close of each workday, the If the pressure level of the compound in the pressure pot shall be checked. pot is not three-quarters fuli,
19、add compound to fill the pot to the maximum permissible level and replace cover. The spray gun shall be turned off and the gun triggered to fill the line and gun with compound. No air shall be pemitted to contact the compound or it will solidify and cleaning of guns or lines will be necessary before
20、 the system can be reused. Spray guns, while attached to lines, shall be inserted into a pail of water (see 3.2.2.3) to prevent clogging of the spray heads for periods of time not exceeding 72 hours. 3.2.2.2 Indeterminate nonuse periods. When periods of nonuse are indeterminate, the compound shall b
21、e replaced in its oriqinal container. or other container affording comparable airtight protection, and the spray-gun and accessories cleaned with water (see 3.2.2.3). 3.2.2.3 Cleaning of spray equipment. MIL-C-6799 compounds are difficult to dissolve after they are dry. Therefore, clean equipment by
22、 blowing the gun clear of compound and flushing with clean water before the compound begins to harden. clogging of lines and spray guns. Any compound left behind will solidify and cause Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- _- NIL-C-237bOD
23、 PA m 7777906 0283273 9 m MI L-C-23760D 3.3 Preparation of surface. Prior to the application of the compound, all surfaces shall be free from corrosion and residue foreign to the item to insure good adhesion. 3.3,l . Cleaning, Clean all surTaces to receive a strippable coating and remove any previou
24、sly applied foreign coatings. accomplished with solvents, detergents, and processes which have no deleterious effect on the surface and which produce surfaces satisfactory for receiving the compound. Protect decals, stencils, neoprene, and rain erosion resistant material coated surfaces by applying
25、a wax conforming to P-W-155. Do not buff or polish the wax coating. are detrimental to acrylics and will scratch, soften, or craze the acrylic. thoroughly dried to remove cleaning solutions or residual moisture. Unless otherwise specified, drying shall be accomplished by one or more of the following
26、 procedures provided it is not injurious to the item. 3.3.2.1 Prepared compressed air, Drying shall be effected by subjecting the item to a blast of prepared dry and clean compressed air. 3.3.2.2 Drying shall be effected by exposing the item to the heated air within a properly ventilated and tempera
27、ture-controlled oven. 3.3.2.3 Infrared lamps. Drying shall be effected by exposing the item to direct heat rays from banks of infrared lamps. 3.3.2.4 Wiping. Drying shall be effected by wiping the surfaces with clean, dry, lin- cloths. 3.3.2.5 Draining. When the final step involves a petroleum solve
28、nt, thorough draining of the solvent shall be required. 3.3.3 Preparation of openings prior to application. Due to the inabi 1 ity of most sprayable, strippable coatings to bridge openings, closures shall be effected by the appropriate method included in paragraphs 3.3.3.1 through 3.3.3.6. 12 inches
29、 shall be fitted with tempered masonite, plywood, fiberboard con- forning to PPP-F-320, or barriers conforming to MIL-B-131 (Classes 1 and 2). Rigid fillers shall be cut approximately 1/4-inch undersize so that felt strips can be attached overlapping the outside edges. be molded to permit intimate c
30、ontact with the surface over which it is applied. A minimum overlap of 1 inch shall be provided wherever possible. The filler shall be secured in place with tape conforming to MIL-T-22085, having a minimum width of 2 inches (see 6.2). The tape shall be secured with a minimum overlap of l/l-inch to t
31、he surface of the item wherever possible. specified in 3.3.3.1 shall be used except that plywood or tempered masonite shall not be used, Cleaning shall be 3.3.1.1 Caution with plastics. Most solvents and cleaning agents 3.3.2 Drying. Immediately after cleaning, the item shall be - Oven. 3.3.3.1 Open
32、ings greater than 12 inches. Openings greater than Flexible fillers shall 3.3.3.2 Openings measuring 6 to 12 inches. The same process 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MI L-C-2376OD 3.3.3.3 Openings measuring 1-1/2 to 6 inches. Barrie
33、r material conforming to MIL-B-131 (Classes 1 and 2) shall be secured in place with tape confoming to MIL-7-22085. 3.3.3.4 . Openings measuring 1/4-inch to 1-1/2 inches. These openings shall be sealed with tape conforming to MIL-T-22085. 3.3.3.5 Openings less than 1/4-inch. These openings in seams,
34、butt joints, screws, or in other places which might prevent application of a continuous film shall be covered with tape conforming to MIL-T-22085. Where MIL-C-6799, Type II coating is used, these openings may also be filled with caulking compound available from suppliers of approved products under M
35、IL-C-6799. This caulking compound can be applied by brush or flow gun. recommended flow gun is the Binks Model No. 31 with No. D-1935 adapter or equivalent. A 4-inch polyethylene nozzle tapered to a 1/16 opening is used with a plastic spreader attached for proper deposit. The caulking compound shall
36、 be allowed to dry for a minimum of 1 hour prior to the application of MIL-C-6799, Type II, Class 1 coating. compounds evenly and not overfill the areas as this will prevent obtaining a continuous seal with the basecoat over the caulked areas, The Care shall be taken to spread the I 3.3.3.6 Screened
37、 coverings. These openings shall be covered as specified in 3.3.3.2. 3.3.4 Tear strip. A tear strip may be utilized to facilitate easy removal of the coating and eliminate the need for a sharp instrument. section of cord, previously dipped in the same compound and dried, shall be placed over the sur
38、face to be coated. The coating shall be applied as specified in 3.6. After drying, pulling up on the cord will initiate stripping. here. A The tear cord shall be labeled: Tear cord, begin depreservation 3.3.5 Masking. When application of these coatings is not intended to cover thTFe surface of an it
39、em, it is often difficult to establish a line of demarcation and, in spraying, the feather edge zone is difficult or impossible to strip. Where applications to a large area are to be avoided, masking paper and masking tape shall be used. Smaller areas may be masked with tape conforming to MIL-T-2159
40、5. Masking materials shall be applied prior to spraying of coating and shall be removed immediately after the final application of the coating compound. Sometimes, removal of masking material where coating has dried will result in partial lifting of the coating. Repair shall be effected by sealing t
41、he edges down with tape conforming to MIL-T-22085. The lifted portion of the coating shall then be pressed down. Since this application is compatible, after drying, the coating will strip as one continuous piece. As an alternate procedure, masking may be accomplished by reducing pressure on the spra
42、y gun and applying a 2 to 3 inch wide bead of coating material completely around the area to be coated. When spraying this bead of coating material, the spray gun should be held approximately 3 inches from the surface. Minor overspray should he removed imediately using a cloth dampened with water. 3
43、.3.6 Coating transparent acrylic surf aces. Transparent acrylic surfaces shall be cleaned and dried as specified in 3.3.1 and 3.3.2. Prior to application of the sprayable, strippable coating, acrylic surfaces shall be coated with plastic polish conforming to P-P-560. After 2 or 3 minutes, it e 5 t P
44、rovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- - _ MIL-C-237bOD PA m 99990b O283293 2 - m - MI L-C-2376OD shall be buffed with a clean white cheesecloth, sheepswool polishing cloth or any soft fabric which will not scratch these surfaces. 3.3.7 Use
45、with preservatives or operational lubricants. These coatincis are adversely affected b.y most preservatives and lubricants as evidenied by the lack-of adhesion; softening, or rupturing of the coating. When the sprayable, strippable coating is to be applied to assemblies or items with critical surfac
46、es treated with these materials, the items shall be wrapped in greasproof barrier material conforming to MIL-B-121, Grade A, or aluminum foil conforming to .QQ-A-1876 prior to the application of protective coat i ng . 3.3.8 Protection of voids. Coating surfaces equipped with attaching holes shall be
47、 plugged or sealed with tape conforming to MIL-T-22085 to assure coating compound does not clog the holes. cork, rubber, wood, or plastic. done while coating is wet. sharp edges, apply preservation tape conforming to MIL-T-22085 or embedded strips of cheesecloth conforming to CCC-C-440 into the firs
48、t coating of the material and allow the coating to dry to a tack-free surface before applying the succeeding covering coats. Plugs shall be made of If plugs are to be removed, this should be 3.3.9 Coating sharp edges. To prevent breaks in the coating at 3.3.10 Installation of vents. When aircraft or
49、 large components are to be comPletelv covered with a strippable plastic coating system and - drainage or ventilation is not provided otherwise, install vents and bleeders in coated areas as follows: 3.3.10.1 Install bleeder vents and drains at the lowest points along the bottom of assemblies such as fuselage, wing butts, engine nacelles, cell closures, and over any overboard drain lines and openings. CAUT ION To prevent possible damage to fuel cells from expan
