Paint coating system

The protective ability of a coating is also dependent upon its thickness. Thicker coatings provide improved protection. However, single thick paint films tend to crack due to internal stress. When long term protection is required, multilayer paint coating systems are applied. 

Long service life is required of paint coating systems for steel structures and other items. In general, paint coating systems for steel structures are classified as general and heavy coatings. 

General paint coating systems are a combination of oil-type rust preventative primer and long oil alkyd resin paint or chlorinated rubber paint (intermediate and overcoats) with a total thickness of less than 150 p,m. These are applied in relatively mild atmospheres such as rural, mountain, and city. 

Heavy paint coating systems are used in severe atmospheres such as marine and industrial, and consist of a spray coating of zinc or aluminum, or a zinc-rich paint primer, followed by several layers of synthetic resin paints such as epoxy, tar epoxy, or polyurethane resins. The total film thickness is more than 250 jxm. 

The most important process affecting the life of a paint coating system is the preparation of the surface to which the coating is to be applied. Pretreat-... 

Zinc or aluminum metal spray Sprayed metal coatings are porous and should be sealed after application by applying a sealer coat (i.e. a thin coat such as an etch primer) or a thinned version of the final coating system. Oil-based systems should not be used. Metal spray coatings can have excellent durability without overcoating with paint and, particularly for aggressive conditions it is preferable to leave them with sealer only. 

To state the means by which the required life of the coating is to be achieved. This includes surface-preparation standards, paints and systems, application, storage, handling and transport, quality control ... 

The potential durability of a coating system can be realized only if it is applied to a suitably prepared surface, in the correct manner under correct conditions. Painting differs from any other industrial processes in that it is not susceptible to operator abuse or adverse environmental influences throughout all stages of the work. 

Steel, whether in structural form or as a sheet, can be protected by many different coating systems, such as paint, plastic materials, concrete and other metals, either singly or in combination (such as a metal coating followed by a paint system, or a plastic coating). Examples of this compound type of... 

The joint should be painted on both sides with the appropriate coating systems (following a suitable surface preparation programme). 

These methods are generally appropriate for either thin-film solvent-based paints or for coatings up to about 150 /xm thickness. The techniques are more usually used for the priming layer of the coating systems. 

The test assembly used originally by Subcommittee Vlll of ASTM Committee B-3 in its comprehensive studies of atmospheric galvanic corrosion had the disadvantage that it depended on paint coatings to confine corrosion to the surfaces in actual contact with each other. In interpreting the results, it was frequently difficult to decide how much corrosion was due to galvanic action and how much to a variable amount of normal corrosion through failure of the paint system. 

Different technical developments have occurred in the coating industry which permit the use of a variety of raw materials. It is possible to formulate surface coatings that are suitable for each and every kind of material. In many cases a number of different coating systems may come into consideration for painting a particular substrate. 

Roller coating Raised surfaces can be painted without masking. Special effects like stripes. Roller applicator, either manual or automatic. Special paint feed system required for automatic work. Dryers... 

These are the most important components of paint. Coatings can be either clear or opaque (containing pigments) and either solvent- or water-based. With solvent-based paints, after application, most of the solvent is lost through evaporation. These solvent-based coatings are mostly alkyds (name derived from alkyl/acid) or modified alkyd resins. Normally they contain 30% polymer solids higher solids content is limited by the increasing viscosity of the system. 

Figure 1 indicates a typical nitroglycerin facility "inside out" wood frame construction at a concrete floor slab. Note that the exterior cant strip, the lead conductive floor cant and the wood cap are all sloped to discourage product build-up and facilitate cleaning. This assembly also indicates spray-on foam insulation as an optional construction item. At Radford AAP this is a safety approved insulation system. The insulation at Radford AAP received a chlorinated rubber paint coating for weathering. 

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