Painting priming

Titanium Dioxide White pigment in virtually all white paints. Prime hiding pigment in most paints. 

Poly(vinyl acetate) is used in latex water paints because of its weathering, quick-drying, recoat-ability, and self-priming properties. It is also used in hot-melt and solution adhesives. 

Cblorina.ted Pa.ra.ffins, The term chlotinated paraffins covers a variety of compositions. The prime variables are molecular weight of the starting paraffin and the chlorine content of the final product. Typical products contain from 12—24 carbons and from 40—70 wt % chlorine. Liquid chlotinated paraffins are used as plasticizers (qv) and flame retardants ia paint (qv) and PVC formulations. The soHd materials are used as additive flame retardants ia a variety of thermoplastics. In this use, they are combiaed with antimony oxide which acts as a synergist. Thermal stabilizers, such as those used ia PVC (see vinyl polymers), must be used to overcome the inherent thermal iastabiUty. 

A cmcial development for zinc phosphate coatings came in 1943 when it was found that more uniform and finer crystals would develop if the surface was first treated with a titanium-containing solution of disodium phosphate (6). This method of crystal modification is a prime reason for the excellent paint (qv) adhesion seen on painted metal articles. 

A frequently cited example of protection from atmospheric corrosion is the Eiffel Tower. The narrow and, for that age, thin sections required a good priming of red lead for protection against corrosion. The top coat was linseed oil with white lead, and later coatings of ochre, iron oxide, and micaceous iron oxide were added. Since its constmction the coating has been renewed several times [29]. Modern atmospheric corrosion protection uses quick-drying nitrocellulose, synthetic resins, and reaction resins (two-component mixes). The chemist Leo Baekeland discovered the synthetic material named after him, Bakelite, in 1907. Three years later the first synthetic resin (phenol formaldehyde) proved itself in a protective paint. A new materials era had dawned. 

Application of protective paints consists of surface preparation of steel, priming coat and finishing coats. Wherever possible, steel should be blast-cleaned before painting. Primers thoroughly wet the metal to promote adhesion of finishing paints and carry inhibitive pigments. For example, red lead oxide will minimize the spread of rust on metal surfaces. The total thickness of fmishing coats must be at least 0.125 mm for adequate protection and life. Four coats of paint usually are necessary to achieve this. 

All painting preparation, priming, finishing and protective coatings shall be in accordance with Specification Number ME-0-JGOO2. 

Anstrich, m. paint, painting, coat varnish dye tint, color appearance, -blndemittel, n. (Painting) binder, -farbe,/, painting color, pigment priming,... 

Protection. Forged parts, rolled structural steel shapes and plates, and castings shall be cleaned, primed, and painted with a good commercial paint or other specified coating before shipment. Machined surfaces shall be protected with a suitable lubricant or compound. 

The paint is sensitive to moisture during storage and application but then becomes exceptionally water-resistant. Its best use is for exterior exposure in an aggressive environment but where the maximum gloss and color retention is required. It is preferable to apply the urethane as a finishing coat over epoxy undercoating and priming. 

In all cases a priming coat of paint containing some form of hexavalent chromium such as zinc or strontium chromate should be used. 

Pickle, galvanise (0-10 mm), 2 coats of paint (one on site) 350 Brushdown, spot prime, 1 top coat —after 12 years 13-7 48-7... 

Wire-brush, 3 coats of paint (two on site) 23-9 Brushdown, spot prime, 2 top coats —4 year intervals 20-2 124-9... 

The metal spraying operation using zinc or aluminium as a protective coating is usually followed by a painting scheme. The choice of sprayed metal and paint scheme depends on the service conditions , but normally this type of system is used on prestige buildings or structures, where longevity is of prime importance and maintenance requirements need to be kept to a minimum. 

In the majority of cases maximum durability will be produced by a multicoat system comprising priming and finishing paints only. Other considerations, however, such as uniformity of colour and smoothness of surface, may make it desirable to introduce intermediate coats, e.g. putty, filler and undercoat. The appearance of the final film or of the final painted structure is of some importance, and a final colour coat, which may contribute very little resistance to corrosion, may be necessary. 

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