Hess’s Paint Film Defects

1 Faults which develop during storage.- 1.1 Cloudiness and sedimentation in varnishes and boiled oils.- 1.2 Thickening, possibly caused by separation, in oleoresinous and synthetic varnishes.- 1.3 Changes of consistency.- 1.4 Separation, sedimentation, precipitation, clouding of liquid driers.- 1.5 Changes of consistency of bitumen and pitch varnishes.- 1.6 The fall of viscosity during storage of cellulose lacquers.- 1.7 Skinning of varnishes, paints, fillers and putties.- 1.8 Settling, changes of viscosity, colour and finish of solvent-based paints.- 1.9 Storage problems of water-based paints.- 1.10 Darkening and other changes of varnishes, paints and thinners.- 1.11 Seediness, bittiness, pigment flocculation.- 2 Difficulties arising during application.- 2.1 Faulty handling of containers.- 2.2 Damage to paint rollers.- 2.3 Damage to brushes.- 2.4 Spraying techniques and spraygun problems.- 2.5 Electrostatic spraying difficulties.- 2.6 Dry spray and cobwebbing.- 2.7 Formation of spraying mist, and exhaust faults.- 2.8 Dipping, flowcoating and curtain coating.- 2.9 Electrocoating and fluidized bed coating.- 2.10 Coil-coating.- 2.11 Foaming of coatings.- 2.12 Sticking together of enamelled parts in a tumbling machine.- 3 Difficulties mainly due to faults in the liquid paints.- 3.1 Excessively thin consistency (as received).- 3.2 Faults due to excessive addition of thinners or additives.- 3.3 Curtaining, running and sagging on vertical surfaces; pulling away from sharp edges and corners; bad flow.- 3.4 Formation of drops on dipping of well-bodied coatings.- 3.5 Difficulties of application due to cold winter temperatures.- 3.6 Brushmarks, bad brushability, wet edge time.- 3.7 Bad flow of varnishes, lacquers and powder coatings. Effect of surface irregularities.- 3.8 Pinholing, pockmarking, cratering, cracked blisters.- 3.9 Cissing and beading.- 4 Faults related to drying and curing.- 4.1 Excessive drying periods — air drying.- 4.2 Excessive stoving or heat conversion times.- 4.3 Tackiness, softness, insufficient hardening of oxidizable air drying paints.- 4.4 Loss of gloss, dulling, matting, differences in gloss of stoved coatings.- 4.5 Flooding and flotation; mottling; silking; striations.- 4.6 Wrinkling, rivelling, webbing, frosting and gas checking of oil-base paints, synthetic resin and bituminous enamels.- 4.7 Sandy, dirty and bitty films, seeding.- 4.8 Lifting of paint films.- 4.9 Bleeding of dyes and pigments contained in coloured coatings.- 4.10 Yellowing and discoloration of coatings during convection stoving or at elevated temperatures.- 4.11 Blooming of stoving enamels (mainly blacks) in gas ovens.- 4.12 Failures in connection with the peculiarities of drying by infra-red radiation.- 4.13 Comparison of the various artificial drying methods.- 4.14 Damage caused by the stoving of coated pure aluminium, aluminium alloy and magnesium alloy.- 5 Defects apparent shortly after application.- 5.1 Formation of blisters and blowholes in filler coats on porous substrates.- 5.2 Blistering, sometimes followed by destruction and lifting.- 5.3 Lack of opacity or hiding or obliterating power.- 5.4 Lack of filling power (or film build).- 5.5 Patchiness in the form of lighter or duller areas in films on newly finished or refinished motor cars, etc..- 5.6 Spotted, cloudy and/or greyish wood lacquer films.- 5.7 Blushing, milkiness and dulling, especially of clear lacquer.- 5.8 Differences of shade in paints by comparison with a standard.- 5.9 Iridescence, rainbow effects, on films of transparent lacquers.- 5.10 Various degrees of gloss and appearance of black enamels.- 5.11 Difficulties on rubbing down of fillers and undercoatings.- 5.12 Difficult polishing of films, smearing on polishing.- 5.13 Difficulties encountered in the forming of coated sheets.- 5.14 Faults in vacuum evaporated metal-lacquer-film systems.- 5.15 Faults characteristic of metallic, hammer and polychromatic paints.- 5.16 Defects developed on wrinkle (ripple, rivel or crinkle) finishes.- 5.17 Some lacquer defects occurring on plastic articles.- 5.18 Loss of gloss and matting of air-drying finishes.- 5.19 Difficulties in coating plastics, or wood impregnated or bonded with plastic.- 5.20 Various difficulties connected with the varnishing of paper, fibreboard or metal.- 5.21 Sweating out, patchiness and dulling of various lacquers, due to oil, wax etc..- 6 Defects related mainly to poor adhesion.- 6.1 Brittleness, poor adhesion, flaking, peeling etc., in solvent-type paints.- 6.2 Unsatisfactory adhesion, brittleness, flaking off etc. on coated metals.- 6.3 Insufficient adhesion to zinc, zinc alloys and galvanized sheets.- 6.4 Insufficient adhesion to smooth, frequently polished metal surfaces.- 6.5 Poor adhesion of stoving finishes on brass surfaces.- 6.6 Bad adhesion to lead or leaded surfaces.- 6.7 Delayed loss of adhesion of paint films over some metals.- 7 Defects of coatings developing in service.- 7.1 Pigment volume concentration (PVC) in relation to film properties.- 7.2 The porosity of surface coatings.- 7.3 Some general reasons for the premature destruction of paint films applied to building structures.- 7.4 Swelling and poor resistance of paint and varnish films exposed to water and moist atmospheres.- 7.5 Blooming, hazing and bronzing of paints and varnishes.- 7.6 Chalking and erosion.- 7.7 Breakdown of water-based and solvent-based paints on new or damp brickwork, concrete, cement-rendered surfaces, asbestos cement, lime plaster.- 7.8 Failures of paint systems on calcium sulphate plasters.- 7.9 Corrosion of painted iron and steel.- 7.10 Lack of effectiveness of chemical pretreatment of steel.- 7.11 Corrosion and efflorescence followed by blistering and lifting of paint and lacquer films on magnesium and aluminium alloys as well as on refined aluminium.- 7.12 Flaking and peeling of air-drying coatings on wood.- 7.13 Flaking and peeling involving water-based coatings.- 7.14 Cracking; alligatoring; checking; embrittlement.- 7.15 Cracking and flaking of lacquer films.- 7.16 Pronounced cracking, alligatoring or checking, staining or formation of brown weathered-out layers of bituminous or tar paints.- 7.17 Colour changes — fading, yellowing and darkening.- 7.18 Mildew (fungi, moulds), algae and moss growth, bacterial and termite activity on paint films.- 7.19 Decay or rotting of wood beneath paint films.- 7.20 Coloured stains on paintwork (as distinct from mould growth).- 7.21 Staining through all kinds of paint films.- 7.22 Tarnishing and other blemishes of metals coated with transparent lacquers.- 7.23 Susceptibility to heat and pressure. Film hardness generally.- 7.24 Faults developing in paints exposed to heat, e.g. on radiators or fires.- 7.25 Lack of solvent and lubricating oil resistance.- 7.26 Faulty resistance to acids and alkalis.- 7.27 Paint failures on photographic equipment.- 7.28 Influence on the taste of food of stoving canning lacquers.- 7.29 Defects caused by faulty application of electrical insulating varnishes.- 7.30 Defects on windings and electrical apparatus due to softening of wire enamel.- 7.31 Defects of impregnations with varnish which develop during service.- 7.32 Defects in oil immersed windings.- 7.33 Open circuits in high speed armatures.- 7.34 Various defects in connection with coating of aircraft.- 7.35 (A) Premature decay of coatings, especially on vehicles.- 7.35 (B) Motor car finishing and refinishing.- 7.36 Paints for railway rolling stock.- 7.37 (A) Ship’s hulls (steel) and underwater structures: preparation and protection against corrosion.- 7.37 (B) Ship’s hulls and underwater structures: protection against fouling.- 7.38 Ship’s holds and superstructures.- 7.39 Destruction of the hulls of wooden ships, harbour constructions and marine piling by marine borers.- 7.40 Paints for steel bridges.- 7.41 Flame retardant paints.- 7.42 Failures due to inadequate specifications.- 7.43 Cost of painting and excessive consumption of material.- 7.44 Practical rules for prevention of fires and explosions in painting shops.- 8 Hazards to the paint user.- 8.1 Toxic hazards.- 8.2 Hazards of fire and explosion.- 8.3 Protective equipment.- 8.4 First aid.- 8.5 Spillages and pollution.- 8.6 References.- Author Index.