CHAPTER 3 FINISH SYSTEMS

TM 43-0139 CHAPTER 3 FINISH SYSTEMS Section I. CLEANING AND TREATMENT OF SURFACES WARNING Before beginning any painting-related activity, read Section II, Safety Summary. 3-1. GENERAL. This chapter describes finish systems. It covers the material to be used and procedures to be followed in the cleaning, treatment, and painting of equipment to provide protection against rust, corrosion, detection, and/or deterioration. For more information on specific systems not addressed in this chapter, refer to applicable finishing documents such as MILSTD-171, Finishing of Metal and Wood Surfaces; MIL-T-704, Treatment and Painting of Materiel; MIL-STD-186, Protective Finishing Systems for Rockets, Guided Missiles, Support Equipment, and Related Materials; MIL-STD-193, Painting Procedures and Marking for Vehicles, Construction Equipment, and Material Handling Equipment; M IL-STD-194, System for Painting and Finishing Fire-Control Material; MIL-STD-709, Ammunition Color Coding; MIL-F-14072, Finishes for Ground Electronic Equipment; and TT-C-490, Cleaning Methods and Pretreatments of Ferrous Surfaces for Organic Coatings. 3-2. SURFACE PREPARATION a. General. Surfaces to be painted must be thoroughly cleaned. All rust, corrosion products, oil, grease, moisture, dirt, fouling organisms, loose and blistered paint, deteriorated areas of old paint, and other surface contaminants will be ' removed prior to painting in accordance with MIL-T-704. Surfaces that require removal of loose paint shall be prepared in the following manner: (1) The initial step shall be to remove all loose paint by light sand blasting or orbital sanding. (2) The edges of good paint surrounding the prepared areas shall be feathered using abrasive sanding disks or stainless steel scouring pads. (3) The newly cleaned areas shall be washed with liquid detergent cleaner (e.g. MIL-D-16791, Type 1) and thoroughly rinsed with fresh water until the surface can pass a water break test. The surface shall be allowed to dry completely; pretreatment should begin within four hours after cleaning. b. Paint Remover. Paint and varnish remover will conform to TT-R-251, Type IV, Class A, low viscosity, for horizontal surfaces, and Class B, high viscosity, to be used for vertical and near vertical surfaces. These paint removers will have minimal effect on CARC coated surfaces, however. For CARC-coated surfaces, use paint remover, epoxy, polysulfide, and polyurethane systems, MIL-R-81294, Type I, according to manufacturer's instructions. c. Solvent Cleaning. Surfaces intended for conventional paint will be cleaned with the currently approved cleaning agent. Surfaces intended for CARC coatings will be cleaned with a solvent conforming to MIL-T-81772 or TT-T-266. Metal surfaces intended for vinyl paints will be cleaned with naptha solvent, Type A, of MIL1-N-15178. Surfaces already painted with vinyl, acrylic, or acrylic nitrocellulose paint will be cleaned with either Toluene, TT-T-548, or Xylene, TT-X- 916, Grade A, prior to over-painting. Mineral-spirit type solvents will not be used on surfaces to be coated with paint because these solvents leave an oily film which interferes with proper adhesion. WARNING Toluene, xylene, and naphtha are highly flammable. Exercise extreme care when using these solvents. Do not expose to heat or open flames. Change 3 3-1