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1950-51 Theatre Catalog, 9th Edition, Page 426 (404)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 426
Page 426

1950-51 Theatre Catalog, 9th Edition, Page 426

. . . . . . in PENING THE SURFACE wxlh fine spray prior to the application of each coal of paint is shown . 33,10]: picture. Typical brushes used in the application of Portland cement base paint are shown in the bottom picture. Here are seen an ordinary scrub brush, window brush. brush which can be used with a handle, and fender brush, is excellent for applying the seal coal to coarse-textured masonry.

The proper amount of water will vary depending upon the fineness of the dry materials and should be determined by trial. The mixed paint should have the consistency of rich cream, except that a slightly thinner consistency is recommended for the first coat applied to open textured types of concrete surfaces, such as concrete masonry units.

The paint should be vigorously stirred for several minutes until it is uniform in color and consistency and all particles are thoroughly wetted. Workability will be improved by allowing the mixture to soak, or pre-hydrate, for 30 to 45 minutes prior to application. Most paints remain in usable condition for 3 to 4 hours after being prepared, although in hot weather some paints, especially those containing calcium chloride, should be used somewhat sooner.

While being used the paint usually tends to stiffen slowly due to chemical and physical reactions and evaporation of the water, and it is common practice to thin the mixture with additional water when necessary to maintain the desired consistency. There seems to be no serious objection to retempering white paints provided it is properly done. The paint should be first vigorously restirred as sometimes this operation will restore its fluidity. Any additional water should be added and thoroughly incorporated in small increments.

In case of tinted paints, it is advisable to avoid the necessity of retempering in so far as possible as the color may be altered slightly if the proportions are appreciably altered. Retempering can be largely avoided by making smaller batches which will be used before the paint stiffens excessively or by keeping the mixed batch in a tightly covered container from which the painteris buckets are filled.

Application of PainteThe surface should be uniformly damp, but With no free water. For obvious reasons, no painting should be done on frozen concrete or when the paint may be exposed to temperatures below 40 degrees Fahrenheit within 48 hours after application. Some paint manufacturers prefer a minimum temperature of 50 degrees Fahrenheit.

The paint should be applied in two coats of the same color. Preferably not less than 24 hours should be allowed between coats; in no case should the second coat be started until the first coat has become sumciently hard to resist marking by the brush being used. In hot, dry weather, the first coat should be slightly moistened before applying the second coat. "Doubling backil or the application of a double thick coat is not conductive to good results and should not be permitted. Three-coat work may be employed if desired, but the extra coat should not be necessary and is seldom worth the additional cost.

Ideal application to coarse textured concrete requires a brush with relatively short, stiff fiber bristles, such as fender brushes (commercially sold for cleaning the underside of automobile fenders) or scrub brushes. In actual practice, however, spray and paint-brush application probably predominate. If the concrete is of smooth or sandy finish, white-wash or dutch-type calcimine brushes are suitable. The paint should be on brushes in

1950-51 Theatre Catalog, 9th Edition, Page 426