Paint Technology and Tests Part 21

No. 21 Raw linseed oil 75% Treated wood oil 25%

No. 22 Raw linseed oil 75% Corn oil 25%

No. 23 Raw linseed oil 75% Cottonseed oil 25%

No. 24 Raw linseed oil 75% Rosin oil 25%

No. 25 Raw linseed oil 50% Soya bean oil 25% Menhaden oil 25%

No. 26 Raw linseed oil 50% Soya bean oil 25% Treated wood oil 25%

No. 27 Blown linseed oil 50% Soya bean oil 50%

No. 28 Raw linseed oil 25% Soya bean oil 25% Menhaden oil 25% Treated wood oil 25%

No. 29 Raw linseed oil 25% Soya bean oil 25% Menhaden oil 25% Corn oil 25%

No. 30 Raw linseed oil 25% Soya bean oil 25% Menhaden oil 25% Cottonseed oil 25%

No. 31 Raw linseed oil 25% Soya bean oil 25% Menhaden oil 25% Rosin oil 25%

No. 32 Raw linseed oil 25% Soya bean oil 25% Treated wood oil 25% Rosin oil 25%

No. 33 Raw linseed oil 20% Soya bean oil 20% Treated wood oil 20% Menhaden oil 20% Cottonseed oil 20%

No. 34 Raw linseed oil 20% Soya bean oil 20% Treated wood oil 20% Menhaden oil 20% Rosin oil 20%

No. 35 Raw linseed oil 40% Soya bean oil 20% Corn oil 20% Cottonseed oil 20%

No. 36 Whale oil 33% Treated wood oil 33% Raw linseed oil 33%

No. 37 Raw linseed oil 25% L. O.[36] 75%

No. 38 Raw linseed oil 50% Raw Chinese wood oil 50%

No. 39 Raw linseed oil 75% Reducing oil[37] 25%

No. 40 Raw linseed oil 50% Soya bean oil 35% Neutral petroleum oil 15%

No. 41 Raw linseed oil 50% Soya bean oil 25% Neutral petroleum oil 15% Tungate drier 10%

No. 42 Linseed oil 25% Soya bean oil 37% Neutral petroleum oil 23% Tungate drier 15%

No. 43 Raw linseed oil 25% Soya bean oil 37% Whale oil 19% Tungate drier 19%

[36] Mixture of boiled tung and soya bean oil, thinned with petroleum and turpentine.

[37] 25% raw linseed oil. 73% petroleum oil. 2% drier--lead and manganese linoleate."

No. 44

Special test on white base of the following composition, in pure linseed oil:

Asbestine 10% Corroded white lead 20% Sublimed white lead 30% Zinc oxide 40%

Upper board of panel reduced with straight turpentine on priming coat.

Second board of panel reduced with wood turpentine on priming coat.

Third board of panel reduced with pine oil on priming coat. Bottom board of panel reduced with petroleum spirits on priming coat.

No. 45

Same pigment formula as No. 44, reduced with:

Pine oil 50% Linseed oil 50%

No. 46

Special test of white base of the following composition, in pure linseed oil:

Corroded white lead 20% Sublimed white lead 30% Zinc oxide 35% Asbestine 15%

No. 47

Cypress panel unpainted.

No. 48

Cypress panel painted with formula No. 1, thinned with benzol on the priming coat.

CHAPTER XV

CEMENT AND CONCRETE PAINT TESTS

=Damp-proofing and Waterproofing.= The decoration and preservation of cement and concrete is a subject which is being given the careful consideration of many technologists on account of the wide usage of cement for structural purposes, and the necessity of properly guarding it against the destructive effects of moisture.

To obtain with various paints decorative effects, and, at the same time, provide a high degree of damp-proofing, is a process quite distinct from that of water-proofing cement and concrete superstructures. The use, in small percentage, of stearic acid solutions, aluminum stearate, marine animal soaps, and other lime-reacting materials, as a component of concrete while it is being mixed, has been in practice for some time, the resulting mixture being used largely upon base-work subjected to water under high pressure. Although some of the materials used for such purposes actually do give to the concrete a high power of water resistance, the degree of waterproofing to be obtained through the use of many such compounds varies to a wide extent, often interfering with the lime-silica reactions, and ultimately affecting the strength of the finished concrete.

=Decorative and Preservative Coatings.= The necessity of obtaining suitable paint coatings for cement and concrete surfaces suggested to the writer a series of tests on paints designed to prevent the destructive action of the lime which, by seepage and other physical action, is brought to the surface, causing saponification of some oil coatings, as well as destruction of color. The tests referred to were carried out during 1908, and although great advances have been made since that time in the preparation of concrete paints, the tests have, nevertheless, afforded information of a valuable nature as indicating the proper methods to follow in the painting of cement, as well as suitable materials to use in the manufacture of cement paints. The tests, moreover, show the comparative durability of a number of paints typical of those prominent in the market at the time the tests were started.

[Ill.u.s.tration: View of Concrete Paint Test Panels]

=Acid Reacting Compounds.= A series of acid reacting washes were included in the tests, having been designed as prime coaters for use previous to the application of oil paints. The application of many of these washes has the effect of neutralizing the lime within cement and concrete surfaces, and often precipitate insoluble lime compounds which aid in filling up the outer voids, thus presenting a surface more suitable to receive oil coatings. To the writer who has since made a careful study of the painting of concrete, it would seem advisable for painters to avoid, when possible, the use of these lime neutralizing washes, as some of them have more or less disintegrating and weakening influences upon concrete. Recent laboratory experiments, however, have indicated that zinc sulphate, an acid reacting material used for many years as a wash for concrete surfaces by Macnichol, actually has a strengthening effect upon cement and concrete surfaces. The more successful coatings of to-day, however, are those which may be placed directly upon the cement and concrete surfaces without the aid of such washes. Several fairly successful paints of this type have recently appeared in the market; some of them being made of acid rosins compounded with vegetable oils. Probably one of the first mixtures of this sort was the so-called suction varnish which the master painter has for years used as a prime coating on plastered walls previous to painting. These suction varnishes generally contain a high percentage of rosin, a material having an exceptionally high acid value and thus lending itself successfully to the neutralization of free lime. It has been claimed, however, by certain practical painters that the lime-rosin compounds formed when such paints are applied to the exterior of buildings, are of a brittle nature and subject to early failure. If this is true, it would seem advisable to use in a concrete paint an oil of a relatively unsaponifiable nature, which would withstand successfully the action of the lime, and, at the same time, prevent disruption of the coating and failure of the color used in the paint.

=Outline of Tests.= The tests referred to as carried out by the writer were made on a brick wall forty feet long, surface-coated with a four-inch coating of Portland cement mortar made of one part of Portland cement and three parts of sharp, clean sand. After the cement had hardened for three days, the solutions under test were applied.