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Read Ebook: The Preservation of the Exterior of Wooden Buildings by Cushman Allerton S Allerton Seward Gardner Henry A Henry Alfred
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Ebook has 26 lines and 7191 words, and 1 pages
THE INSTITUTE OF INDUSTRIAL RESEARCH
THE INSTITUTE OF INDUSTRIAL RESEARCH
THE PRESERVATION
OF THE
EXTERIOR OF WOODEN BUILDINGS
ALLERTON S. CUSHMAN, Director THE INSTITUTE OF INDUSTRIAL RESEARCH
AND
HENRY A. GARDNER, Asst. Director IN CHARGE DIVISION OF PAINT TECHNOLOGY, THE INSTITUTE OF INDUSTRIAL RESEARCH
WASHINGTON 1911
WASHINGTON, D. C. PRESS OF JUDD & DETWEILER, INC. 1911
PREFACE
For a number of years the writers have been making a study of industrial problems and have been publishing the information which they have acquired, regarding the value of various structural materials, for the benefit of consumers as well as producers. The Institute of Industrial Research has received so many requests recently for information in regard to just what paints should be selected for the protection and decoration of houses and other buildings that it has seemed best to sum up the subject in the form of a special pamphlet or bulletin. It is only after years of investigation work carried on by the authors, both separately and in co-operation, that any review of the work has seemed possible, for only recently have the results of tests carried on in a number of different localities seemed to justify a definite opinion in regard to the best selection of exterior paints. No attack on any one paint material is here included, but the value of each has been carefully weighed, and the attempt is made to discuss them in the light of experience and knowledge. It is the authors' intention in this bulletin to put into the hands of architects and paint users who may not be thoroughly familiar with the technical properties of paint materials, information which will enable them to make a proper and intelligent selection of paints for the preservation and decoration of the exterior of wooden buildings.
The Preservation of the Exterior of Wooden Buildings
Note.--For a more detailed account of the lumber question, see "Modern Lumber as a Problem for the Painter," read by John Dewar, at the Convention of Master House Painters' and Decorators' Association of Pennsylvania, January, 1911, Pittsburg, Pa.
Photographs Showing Different Forms of Decay Exhibited by Improperly Made Paints
The use of white lead has been condemned in some parts of this country as well as abroad, because of its alleged poisonous properties. While it is true that lead poisoning may occasionally occur in some factories where the workman and his conditions are not properly safeguarded, it is, nevertheless, a fact that lead poisoning very seldom occurs among painters of experience and cleanly habits. Carelessness in mixing white lead is, fortunately, a practice almost obsolete among modern painters. The use of paints already ground in oil by means of machinery to a pasty condition, allowing easy working and reducing, obviates the danger of lead poisoning from any such cause as this, even though the percentage of lead in such paints is in preponderance. Recent efforts that have been made by the legislatures of certain States to brand lead paints as poisonous are not only unnecessary, but show a complete ignorance of the problem.
A white paint must be possessed of sufficient opacity to efficiently hide the surface upon which it is placed, when three coats are applied for new work or two coats for repainting work. Mixtures of the white leads and zinc oxide, with the latter pigment running not over 55 per cent, will easily produce such a result and wear well. It is generally deemed advisable, however, by most manufacturers to take advantage of the excessive opacity of such mixtures, which allows the introduction of moderate percentages of those inert pigments which give greater strength and other desirable features to a paint. The percentage of natural crystalline inert pigments to add to a white paint made of lead and zinc must, however, be moderate and insufficient to detract materially from the hiding power of the paint.
Note.--Pigments such as silica, barytes, China clay, and asbestine are thoroughly inert. Recent investigations have proved that they accelerate the drying of linseed oil, but this is not due to any chemical action they exert, but rather to their physical action in distributing the mass of oil in which they are ground, and thus allowing a greater surface to be exposed to the oxygen of the air.
It is also possible that some of the inert pigments may stimulate oxidation by catalytic or contact action, although they are not chemically active in themselves.
Tinted paints possess greater hiding power than white paints, and the above proportions would be somewhat changed for a tinted paint containing any percentage of coloring material. Tinted paints are, moreover, far more serviceable than white paints, as will be shown later.
In the opinion of the writers, a majority of the paints sold by reputable dealers and made by reputable manufacturers in this country are not only made from the best linseed oil and highest-grade pigments obtainable, but are put up in a form ready for the painter to thin down with full oil or turpentine reductions, either for priming work or to be used without reductions for finishing coats. The large metropolitan painter who wishes to make his own tints and shades may, however, prefer to have his mixed pigment paint ground by the manufacturer in heavy paste form for certain purposes.
The painter and manufacturer have come to understand that certain grades of asphaltum and paraffine distillates are equally as satisfactory as turpentine for use in paints for exterior purposes. Those volatile oils which are distilled from crude oil with either a paraffine or asphaltum base and possessed of boiling point, flash point, color, and evaporative value approximating similar constants of turpentine, are excellently suited to partly, and in some cases wholly, replace turpentine in exterior paints. A little additional drier added to paints thinned with these materials will cause oxidation to take place in the proper time.
Prominent master painters have shown that benzol, a product obtained from the distillation of coal tar, differing from benzine, a product obtained from the distillation of petroleum, is a valuable thinner to use in the reduction of paints for the priming of resinous lumber such as cypress and yellow pitch pine. The penetrating and solvent value of benzol is high, and it often furnishes a unison between paint and wood that is a prime foundation to subsequent coatings, preventing the usual scaling and sap exudations, which often appear on a painted surface. Because of the great solvent action of benzol, however, this material should never be used in the second and third coatings. These facts will doubtless interest the Southern painter, who has so much wood of a refractory nature to paint.
The flax crop conditions have been most discouraging during the past two years, and the natural shortage of seed has caused a rise in the price of linseed oil, which has necessitated a rise in the price of paint. The added protection to be secured, however, through the frequent application of paint far outweighs any increased cost which has been caused by the rise in price of the raw commodities entering into the composition of paint.
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