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1950-51 Theatre Catalog, 9th Edition, Page 422 (400)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 422
Page 422

1950-51 Theatre Catalog, 9th Edition, Page 422

THE EFFECT OF TIME ON LACQUER. Photograph at the left (magnification: x6) represents a good lacquer film after six months' exposure in Florida. About all that can be seen is the slight orange peel from spray application. This could also illustrate fresh lacquer. The photograph at the right (also

to a few hours, can be easily adapted to almost any requirements by the choice of suitable solvents and diluents.

The answer to the question of durability of lacquer on exterior surfaces is found in the fact, for many years, about half the automobiles have been finished with this type of lacquer.

In most cases, nitrocellulose lacquer may not safely be applied directly over oil paints. The lacquer liquids soften and swell the paint coating and cause lifting. A thin coating of dewaxed shellac varnish over the paint will prevent this.

Lacquer may be removed by the use of lacquer solvents. Each manufacturer supplies removers adapted to his own product. Removers are also used for the correction of faults, for the removal of spots, and so forth.

Lacquer Enamels - Highly pigmented lacquers are known as lacquer enamels.

Flat Lacquers are generally clear lacquers to which has been added 2 to 5 percent of a flattener for the purpose of eliminating the high gloss of the original clear lacquer. Flat lacquers are recommended only for interior use on equipment such as wood furniture and the like.

Cracking Lacquers sometimes designated as crackle finishes are formulated so that the coat will develop fine cracks in an intricate, pleasing pattern or "cobweb" effect. These are applied over a foundation coat of hard, drying lacquer. Wrinkle finishes are similar.

Crystallizing Lacquers are those containing in solution substances which, as the volatile solvents evaporate, will crystalize in beautiful patterns of pleasing colors. The color and the pattern depend on the substance selected.

Brushing Lacquer, as the name implies, is a lacquer to be applied by means of a brush in the same manner as paints, enamels, and varnishes.

Modern brushing lacquers are compromises between synthetic resin finishes and nitrocellulose lacquers, since, in addition to nitrocellulose, they ordinarily contain a high proportion of synthetic resin, thus improving the brushability of the succeeding coats.

Naturally, the drying time of these lacquers must be prolonged sufflciently to permit of easy brush application. By slow evaporating solvents, together with a suitable diluent, brushing lacquers which brush as easily as oil-base varnishes and enamels can be readily formulated for many purposes, particularly as architectural finishes.

Lacquering Process

The actual lacquering procedure, will differ with different industries and the material to be coated, but the following indicates the general practice.

Priming Coat-Ordinary metal oil primers and thin pigmented lacquer base primers are applied with the spray machine or with the brush.

Surfacer-Heavily pigmented lacquer base coating, rubbed with sandpaper and water, or fine abrasive, is applied in one or more coats as required. This coat is also sanded to a level surface.

Finishing Coat-Non-settling lacquer enamel, either pigmented or clear, usually requiring dilution with a lacquer thinner. If a dull finish is required, a special rubbing compound or pumice and water is used on a felt pad, as with ordinary varnish. The main requirement for its successful use of primers is the cleanlineSS of the metal. Any foreign material of an oily or waxy nature affects the adhesion to a large degree. Almost always primers are applied by spraying. Brushing does not give satisfactory results, since the finishing coats soften the primer and brushing has a tendency to pick up the primer, intermixing it with the finishing coats.

Priming Coats # Lacquer primers, valued for their bonding or adhering qualities and the ability to retain this property after exposure, are essentially clear lacquers having exceptional adhesion to the particular surface for which they are designed. They may or may not be pigmented, but mostly do contain pigment but only enough to guide the operator in obtaining a smooth, even coat.

Lacquer primer is a first coat applied on a surface that is to be coated with lacquer, this first coat to contain nitro early as six months.

x6) represents the typical failure of a lacquer by checking and contraction of the film. This lacquer was not well formulated and showed checking a:

Lacquers are not recommended for exterior usage on wood for the reasons pictured here. (Sherwin-Williams photographs.)

cellulose, resin, plasticizer, and solids. It may not contain pigment. Usually it does not contain sufficient pigment to permit sanding. A special type, however, of lacquer primer which is used as a first coat on wood is usually made up with inert pigment so that it does sand freely.

For an unpigmented lacquer, priming or foundation coats are similar to the body coats, with the exception that it usually contains more resin, oil, and plasticizer to insure adhesion.

Lacquer priming coats for wood are commonly called sealers.

Over stained wood, special coatings not permeable by the lacquer (dewaxed shellac varnish, for example) are used to prevent bleeding.

For pigmented lacquers, or nitrocellulose enamels, the foundation coat is also pigmented.

Sealers and Surfacers #- A lacquer sealer is formulated somewhat the same as lacquer primer, and it must exhibit good bonding properties and, at the same time, successfully seal the old surface over which it is used. Its chief office is that of preventing the finishing lacquer from lifting or otherwise disturbing the original nnish. Great care should be exercised when applying sealers over old finishes, as it has been found through experience that an unduly thick coat has a tendency to peel on exposure.

Generally, however, lacquer sealer is considered to be the first clear coat of lacquer applied to a wood surface#for example, furnitureveand is designed chiefiy to keep the grain from raising, lie on the surface of the wood rather than penetrating it, and being an easy sanding material so that, when sanded, a smooth even surface is obtained for application of the finishing coats which do not penetrate through the sealer, thus giving a smooth even finish without showing ridges due to the grain of the wood and the like.

The lacquer surfacer forms an intermediate coating between the primer and finishing coats when rough, scratched, or uneven surfaces are being finished. Its function is to give fill or build that fills in the rough uneven surface, and,

1950-51 Theatre Catalog, 9th Edition, Page 422