Proper Paint System

A paint system is a combination of coats of paint that 

The following operations performed by paint systems eould never be performed by a single coat of paint. 

This operation provides the needed surfaee integrity. Applying a surfaee eonditioner to a ehalky stueeo surfaee before applying an emulsion paint binds the substrate together. 

This operation provides eolor without film buildup. 

This operation involves building up low spots in the surfaee by filling and sanding. Filling the surfaee prevents surfaee irregularities from photographing through the paint system. 

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The corrosion of metals from exposure to water can be prevented if the proper paint system is correctly applied according to the following guidelines. 

Proper paint and vacuum metalizing systems, metal plating procedures, welding, and adhesives are some of the other important considerations in the fabricating process that must be factored into a program before a new plastic can be fully accepted. 

Surface Preparation The steel surfaces to receive the membrane lining must be smooth, free from pits, millscale, weld splatter, and lap welds. Corners must be rounded to an internal and external radius of % inch minimum. The surface must be sandblasted just before application of the membrane on interior surfaces and a paint system on exterior surfaces. Sandblasting should be in accordance with specifications supplied by the manufacturers of the membrane and protective coating system. This may require welding inside corners and then grinding to the proper radius. 

Many test results and a great deal of engineering data over many years have shown that the most important single factor influencing the life of a paint is the proper preparation of the metal surface. This factor is, generally, more important than the quality of the paint that is applied. In other words, a poor paint system on a properly prepared metal surface usually outperforms a better paint system on a poorly prepared surface. A well-prepared surface is the foundation on which the paint system is built. 

Two types of paint systems were used for experiments. First system used was zinc phosphate primer (50 % Zn as compound) with micaceous iron oxide (MIO) as intermediate coat followed by polyurethane (PU) as top coat denoted as ZP. Other system used was zinc rich primer (80 % Zn as dust) with MIO as intermediate coat and PU as top coat denoted as ZR. This system is costlier with respect to ZP and considered for laboratory evaluations purpose only. ZP is designed with respect to places where test panels are deployed for exposure based on manufacturers catalogues and standards [4]. These systems possess good resistance from water permeability, weathering, abrasion and good adhesion to maintain a proper barrier to the environment. The drying mechanism of the systems is the reaction between epoxy resin and polyamide. The details of each paint system used comprising primer, intermediate and top coats with the respective layer of film thickness are shown in Table 2.2. 

Surface preparation, along with the proper application techniques of the paint system, is extremely important if adequate protection is to be achieved. Table 7.5 on page 111 provides a summary of the various recommended surface preparation specifications. The actual specifications to be used will be determined by the coating system to be applied. 

This specification covers an alkyd painting system for new, unrusted, untreated, galvanized steel. This system is suitable for use on parts or structures exposed in Environmental Zones lA (interior, normally dry) and IB (exterior, normally dry). The primer has good adhesion to clean galvanized steel but does not adhere properly to rusted galvanized steel. Painting System No. 1.04 should be specified for this condition. The finish paint allows for a choice of durable, fade-resistant colors. 

This specification outhnes a three-coat epoxy-polyamide painting system for the protection of steel surfaces subject to industrial exposure, marine environments, and areas subject to chemical exposure such as acid and alkali. This system, when properly applied and cured, is capable of giving excellent protection to steel surfaces in Environmental Zones 2A (frequently wet by fresh water), 2B (frequently wet by salt water), 3A (chemical, acidic), 3B (chemical, neutral), and 3C (chemical, alkaline) but not in potable water tanks. Although the coating herein specified has exhibited good chemical protection, its resistance against specific chemicals should, in the absence of applicable case histories, be appropriately tested. 

This problem usually occurs when water is trapped behind the paint. If the paint system is not sufficiently resistant to water for the intended exposure, water can penetrate the surface. However, peeling is usually caused by water that has entered through breaks in the paint surface due to cracks in the wood or open joints that were not properly caulked. Special care should be taken to caulk joints around doors and windows. 

Detecting known substances, and determining their quantity, is also important. In synthetic research, it is essential to know the relative proportions of various reaction products. In manufacturing, it is important to detect any impurities in the product and to determine whether they are present in a significant amount. Analytical characterization is critical in pharmaceutical products, for instance. Products for practical uses—paint or adhesives, for example—will typically consist of several components. For proper and reliable performance it is important to measure the amounts of each of the components as part of a manufacturing quality control system. Manufacturers also commonly need to analyze the raw materials they receive, measuring the amounts of various substances in them to be sure that the material meets their requirements. Before it can be correctly processed into steel, iron ore must be analyzed to determine how much of other components need to be added to produce a metal alloy of the desired composition and properties. 

Pigment slurries are one of the major components in paints and coatings that contribute to or affect the performance of a formulation. The nature of pigment slurries makes them extremely susceptible to microbiological contamination that can degrade the final formulation. Often biodeterioration can be prevented with plant sanitation and the use of a preservative, but formulators must not rely on the precept that a particular preservative that works today will always remain effective down the road. In complex environments, contaminants can enter the system at different points, or a formulation change may render the original preservative less effective. Manufacturers must remain aware of trends in the industry to ensure their products are properly protected. 

Fire Retardent Paints. Fire retardant paints are based on chlorinated rubber and chlorinated plasticizers with added SbO. These reduce the rate of spread of flames. Addn of NH4H2PO4, PE, or dicyandiamide produces an intumescent or swelling paint that forms a thick insulating layer over the surface to which it is applied when exposed to flames Fire retardant paints do not control fires and are no substitute for an automatic sprinkler system. They are best used where the only hazard is exposed, combustible, interior finish materials or in isolated buildings where sprinklers will not be installed. The paint must be applied at the rate specified on the container if spread thinner the proper... 

Students will classify watercolor, poster paint, and acrylic paint in proper categories under a classification of matter system. 

Synthetic polymers, often possessing uniquely desirable working proper- ties and physical appearance, are finding ever wider use by artists and conservators. For example, poly (vinyl acetate) emulsions have been used for collages (4,5), the production and conservation of books (6,7), and the conservation of textiles and paintings (8,9). It has become essential to study the behavior of new materials and to evaluate their long-term behavior as individual materials and as components in the complex systems which make up artistic and historic artifacts. Our experience with a wide range of natural and synthetic polymers—e.g.,... 

The Roman aristocracy had greater access to lead vessels and cosmetics containing lead compounds. It is believed that their life expectancy may have been as low as 25 years because of lead poisoning. In the body, lead accumulates in bones and the central nervous system. The production of hemoglobin is inhibited by lead because it binds to the enzymes that catalyze the reaction. High levels of lead cause anemia, kidney disfunction, and brain damage to occur, and the accumulation of lead interferes with proper development of the brain in children. Because of their toxicity, lead and its compounds are used much less today as paints or glazes than they were in earlier times. 

Postdeposition plasma modifications to the plasma polymer of TMS have been seen to greatly improve bonding to various primers and paints [18-20]. One particular system has been observed to have tremendous adhesion between plasma-coated A1 alloy panels and paint applied to them. This system involves cathodic DC plasma deposition of a roughly 50-nm primary plasma polymer film from TMS onto a properly pretreated alloy substrate, followed by the deposition of an extremely thin fluorocarbon film by DC cathodic deposition of hexafluoroethane (HFE). It was the superadhesion aspect of this particular system that triggered the series of ESR studies [3,21]. 

Faint adhesion although a factor of wet-out, Is also controlled by solvent "bite", and post molded freedom from IMR exudation or bleed out, a topic previously reviewed. Obviously, the selection of a solvent system for a paint formulation must be properly addressed In order to eliminate, or, at the very least, minimize this type of paint adhesion deficiency. Some of this topic Is further discussed under the section titled Theoretical Cons lderatlons. 

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