“InTable No. 2there is shown the rating obtained by those panels which were considered by the committee as meriting from 8 to 10, and having given the best all-round service.
Comparison of Results.It is of interest to compare withTable 2 of the above report,Table 2 of the 1910 reportof Committee U of the American Society for Testing Materials. Both charts show the highly inhibitive pigments to be in the lead.
(Only resistance to corrosion was considered, and onlypigments which were common to both tests are included)
The writer has recently made a careful inspection of the panels painted with single pigment paints, and has made the following brief summary of the characteristic appearance of each.
Panel No. 1—Dutch Process White Lead.The excessive chalking which took place began to disappear at the end of a year, being washed away by the rains and carried away by the winds, so that there was left upon the surface but a thin coating of pigment, insufficient to give good protection. Slight corrosion was apparent beneath the film.
Panel No. 2—Quick Process White Lead.In the same condition as Panel No. 1.
Panel No. 3—Zinc Oxide.Panel covered with thin lateral streaks of rust, due to the admittance of moisture in cracks caused by brittleness of film. Result doubtless due to insufficient amount of oil used with pigment. Removal of film shows steel very bright except where cracks have formed.
Panel No. 4—Sublimed White Lead.Although sublimed white lead chalked very heavily, the chalked pigment seemed tobe tenacious and adhered to the plate, presenting an excellent surface with absence of rust. Film of good color and quite elastic.
Panel No. 5—Sublimed Blue Lead.In same condition as Panel No. 4, but color has slightly faded.
Panel No. 6—Lithopones.Lithopone was early destroyed, as is usual with this pigment when used alone on exterior surfaces. It became rough and discolored, presenting a very blotchy appearance and disclosed the formation of rust working through the film.
Panel No. 7—Zinc Lead White.In general good condition with the exception of the color, which is slightly dark. Medium chalking was apparent but only very slight corrosion appeared.
Panel No. 9—Orange Mineral.In excellent condition, showing a good firm surface with no checking or corrosion apparent. Shortly after exposure the film became covered with a white coating of carbonate of lead, which indicates action of the red lead with the carbonic acid of the atmosphere. Removal of this white coating with water discloses the brilliant color of the unaffected portion of the red lead.
Panel No. 10—Red Lead.In same condition as Panel No. 9.
Panel No. 12—Bright Red Iron Oxide.In general good condition. Film intact and unfading in color.
Panel No. 14—Venetian Red.Similar to Panel No. 12, but slight corrosion apparent beneath, in localized spots, and film showing slight wart-like formations.
Panel No. 15—Prince’s Metallic Brown.Similar to Panel No. 14.
Panel No. 16—Natural Graphite.Deeply pitted in spots, showing bulbous eruptions, indicating the stimulative nature of this pigment.
Panel No. 17—Artificial Graphite.In same condition as Panel No. 16.
Panel No. 19—Lampblack and Barytes.Although the film seems to be intact, there are apparent abrasions of the surface showing stimulative corrosion effects of a pronounced nature.
Panel No. 21—Carbon Black and Barytes.In same condition as Panel No. 19.
Corrosion Pits on Graphite PanelCorrosion Pits on Graphite Panel
Corrosion Pits on Graphite Panel
Rust on Stripped Grpahite FilmRust on Stripped Graphite Film
Rust on Stripped Graphite Film
Wire with Stimulative Carbon PaintSection of Wire Painted with a Stimulative Carbonaceous Paint
Section of Wire Painted with a Stimulative Carbonaceous Paint
Corroded and Pitted Surface of Plate with Stimulative PaintCorroded and Pitted Surface of Plate Painted with Stimulative Paint
Corroded and Pitted Surface of Plate Painted with Stimulative Paint
The longevity of lampblack and carbon black paint films when applied to wood has been attributed to the slow drying nature of these pigments when mixed with oil. It is assumed that they have the property of keeping the oil in a semi-drying condition, which will not disintegrate as early as when the oil is thoroughly dried to linoxyn. If this is true, it would seem advisable to use with hard-drying pigments, a proportion of some oil that is semi-drying in nature or one which will leave a film not too hard. Soya bean oil, wood oil, and fish oil present themselves as candidates for such use. How they will work in practice, however, is a question not yet determined. On the other hand, it is well known that these pigments require enormous quantities of oil in order to grind to a working consistency, and it is possible thatthe life of such coatings is due rather to the property of these pigments, of taking up large quantities of oil, than to their effect upon the slow drying of oil. Excessive oil carrying, however, should be avoided, as shown by the early failure and pitting of those carbon black and lampblack paints ground with very large quantities of oil, as is the usual practice. When these carbon and lampblack pigments were ground with barytes (which is a heavy pigment and requires only about 9 pounds of oil to 100 pounds of pigment, as against 175 pounds of oil to 100 pounds of lampblack), it was found that the lampblack and carbon black paints were reinforced and made more suitable for actual practice. The stimulative nature of these black pigments, however, asserted itself in both cases, and large pittings and eruptions were evident at the end of a year. Carbon black, lampblack, graphite, or any other good conductor of electricity should never be placed next to the surface of iron. They are good as top-coatings, but not as prime-coaters. Some pigments are stimulators of corrosion, because they contain water-soluble impurities that hasten the rusting, while others, like graphite, hasten it simply because, being good conductors, they stimulate surface electrolysis.
Panel No. 20—Willow Charcoal.In excellent condition throughout. Presence of small quantities of potash may be responsible for the inhibitive nature of this black pigment.
Panel No. 24—Ochre.While the film seems intact, it has a very mottled appearance and examination shows eruptions of rust through the film, in several places.
Panel No. 27—Natural Barytes.Within a year the film became pin-holed, and corrosion was apparent. At the end of three years very little of the pigment was left upon the plate, having chalked and scaled off. Barytes has proved its usefulness as a constituent of a combination type of paint, but it should not be used alone.
Panel No. 28—Blanc Fixe.In the same condition as Panel No. 27, but slightly more chalking and disintegration was shown.
Panel Painted with Blanc FixePanel Painted with Blanc Fixe. Right Side Stripped of Paint to Show Corrosion
Panel Painted with Blanc Fixe. Right Side Stripped of Paint to Show Corrosion
Scaled Whiting FilmsScaled Whiting FilmsChemically Active Pigments and Their Effect After Eighteen Months’ Wear
Scaled Whiting Films
Chemically Active Pigments and Their Effect After Eighteen Months’ Wear
Effect of Chemically Active Pigment on OilPlate Showing Effect of Chemically Active Pigments on Oil after One Year’s Wear
Plate Showing Effect of Chemically Active Pigments on Oil after One Year’s Wear
Panel No. 29—Whiting.Plates coated with calcium carbonate or whiting in oil presented a very fair appearance at the start of the test, but they soon began to chalk and disintegrate. It is well known that whiting, being alkaline, has the property of acting on oil and causing its early disintegration by saponification. As a matter of fact, six months after the whiting plates were exposed, crumbling of the surface appeared, and twelve months was sufficient for the total destruction of the paint. At this time the rusted surface of the plates which had been painted with calcium carbonate, seemed not to rust as fast as those plates which were exposed without paint coatings, and the rust which had formed appeared to be of an even, fine texture. On the lower left-hand corner of these plates had been lettered the figures “29” and “30,” using lampblack in oil. One of the most remarkable things which appears on the fence to-day is the perfect condition of these lampblack letters over their priming coat of calcium carbonate, standing out in clear relief against the rusted metal. This test would suggest, therefore, that if the surface of metal is properly protected with a pigment whichis slightly alkaline or inhibitive in nature, and then topped with a good weather-resisting material, such as lampblack, graphite or carbon black, good results would be obtained. Further tests will be made to determine the value of this suggestion.
Panel No. 30—Precipitated Calcium Carbonate.Showed more rapid destruction than Panel No. 29.
Corrosion Adhering to Film of Panel Painted with GypsumCorrosion Adhering to Film Stripped from Panel Painted with Gypsum (Calcium Sulphate)
Corrosion Adhering to Film Stripped from Panel Painted with Gypsum (Calcium Sulphate)
Panel No. 31—Calcium Sulphate.Under the paint film of gypsum, rust soon appeared, showing that the film was not a good excluder of moisture. Although the film remained intact, rusting progressed throughout the test and considerably darkened the color of the paint.
Panel No. 32—China Clay.This pigment gave excellent service for eighteen months. Afterwards indications of corrosion were shown, and apparent breakdown of the film was indicated.
Panel No. 33—Asbestine.In the same condition as Panel No. 32.
American Vermillion in Excellent StateExcellent Surface shown by American Vermilion after nearly Four Years’ Exposure
Excellent Surface shown by American Vermilion after nearly Four Years’ Exposure
Panel No. 34—American Vermilion.This pigment has given perfect protection to the plates. The film is strong and elastic, and upon removal reveals the bright steel. No chalking, checking, discoloration, or other signs of paint failure are shown. It would appear that the inhibitive characteristics of this pigment are pronounced, and it promises to give efficient service for several years more.
Panel No. 36—Lead Chromate.This panel is in generally fair condition, but slight checking is shown.
Cracked Negative of Perfect Condition of Plate Painted with ZincPerfect Condition of Plate Painted with Zinc Chromate; One Half Stripped. (Negative cracked)
Perfect Condition of Plate Painted with Zinc Chromate; One Half Stripped. (Negative cracked)
Panel No. 39—Zinc Chromate.This panel is in condition similar to Panel No. 34, presenting a perfect appearance, with decided maintenance of color, elasticity of film, and freedom from any bad characteristics. It has proved to be one of the highest type rust inhibitive pigments.
Panel No. 40—Zinc-and-Barium-Chromate.Although the color of this pigment is not very pleasing, it has proved itself to be the equal of zinc chromate in its protective value.
Panel No. 41—Chrome Green.In excellent condition. Presents an appearance similar to Panels Nos. 34 and 39. Its surface is perfect and will doubtless give service for many years.
Panel No. 44—Prussian Blue.This panel stands forth as the most wonderful moisture-excluder in the whole test, its surface presenting an appearance similar to a varnished plate, even after three years’ exposure. Action between the pigment and the oil, resulting in the formation of iron linoleate, may account for this property.
Panel No. 45—Prussian Blue.In same condition as Panel No. 44.
Panel No. 48—Ultramarine Blue.Soon after this test was exposed, early vehicle decay and excessive chalking were observed. The admittance of moisture may have caused the formation of acid with the sulphur content of the pigment, which would account for the rapid corrosion which followed. It is of a pronounced stimulative type. The effect of stimulative under-coatings is well shown on some special plates on the fence, which when received were not pickled before painting, but had upon their surfaces the ordinary coating of mill scale. Over this had been stencilled in a triangular form the trade mark of the manufacturer. The stencilling material was made of ultramarine blue. When these plates were painted with some of the special paints, and exposed, the stimulative nature of the ultramarine blue began to assert itself, and within a short time, wherever the stencil marks were located, signs of rust began to appear through the coatings of top paint which had been applied. Corrosion under these stencil marks became so great that the trade mark was plainly outlined in letters of rust. This would seem to be final proof that pigments of a stimulative nature should never be used for the priming of iron and steel.
Panel No. 49—Zinc-Lead Chromate.In excellent condition throughout, with a smooth surface and showing no corrosion. Stands in the same class as Panels Nos. 34 and 39.
Effect of Stimulative PaintEffect of Stimulative Paint. Manufacturer’s Trade Mark Stencilled on Bare Metal in Triangular Form, showing Through Subsequent Paint Coating
Effect of Stimulative Paint. Manufacturer’s Trade Mark Stencilled on Bare Metal in Triangular Form, showing Through Subsequent Paint Coating
Panel No. 51—Black Magnetic Oxide of Iron.In excellent condition.
Decoration and Sanitation.The proper decoration of the interior of dwellings and public buildings has become of even greater importance than the protection and decoration of exteriors. There is, moreover, an increasing demand for harmonious effects and the production of more sanitary conditions than have prevailed in the past. Up until a few years ago a great variety of wall papers of more or less pleasing appearance were almost exclusively used for the decoration of walls in the interior of buildings, and their application was commonly considered the most effective means of wall decoration. There seems to be no question, however, that the use of wall paper is steadily decreasing, and that the art of interior decoration is undergoing a transition to the almost universal use of paint.
Modern progress demands the maintenance of sanitary conditions for the benefit of the public welfare, and there is no doubt that from the standpoint of sanitation and hygiene, properly painted wall surfaces are far superior to papered walls. There is an abundance of evidence which shows that dust germs may easily be harbored, and thus disease transmitted from wall paper. In the tenement houses, which are common to the larger cities, and to a lesser extent in the dwellings found in smaller communities, where tenants are more or less transient, the continued maintenance of sanitary conditions presents a difficult problem. Infectious and epidemic illnesses generally leave behind bacilli of different types, which may find a culture medium in the fibrous and porous surfaces presented by wall paper, backed up as they invariably must be by starch, casein, or other organic pastes. Occasionally the restrictions of local boards of health provide in such events for proper fumigation, but too often no precautions are taken to destroy the disease germs which are caught in the dust which collects on wall paper. As a rule, both tenant and landlord are oblivious to all conditions which cannot be readily seen or detected. Burning sulphur, one of the most effective means of fumigation, will generally cause bleaching and consequent fading of the delicate colors used in printing the designs upon wall paper. Washing of the paper with antiseptic solutions will destroy its adhesiveness to the plaster and often cause bulging and general destruction.
Hospital Practice.In hospitals, where it is necessary to maintain sanitary conditions, the walls are invariably painted, and requirements should demand the use of paints which can be washed frequently, so that there will be no possibility of uncleanliness. Inquiry made of a prominent surgeon[38]connected with one of the large metropolitan hospitals substantiated the writer’s findings regarding the greater sanitary value of wall paints, and brought forth the information that in hospitals under construction provision had been made for the finishing of walls so that a hard, non-absorbent, and washable surface might be obtained. The same authority stated that the common practice, in apartments and tenements, of covering the old wall paper over with a layer of new each time a tenant moved in, should be condemned, and that from a hygienic standpoint the use of sanitary wall paints should be advocated in all dwellings as well as public buildings.
[38]Dr. F. F. Gwyer, Cornell Uni. Med. Col., New York City.
[38]Dr. F. F. Gwyer, Cornell Uni. Med. Col., New York City.
If such conditions are maintained in hospitals, where special attention is paid to sanitation, it would appear that similar precautions should be equally as necessary in public buildings and in dwellings—wherever, in fact, people congregate or live.
Sanitary Wall Paints.There have recently appeared in trade a number of wall paints composed of non-poisonous pigments ground in paint vehicles having valuable waterproofing and binding properties, and of a nature to produce the flat or semi-flat finish that has become so popular. Such paints produce a sanitary, waterproof surface, which permits of frequent washing. By their use it is possible to secure a more permanent and a wider range of tints than can be obtained with wall paper, as they are produced in a myriad of shades, tints and solid colors, from which any desired combination may be selected.On the border or on the body of walls decorated with such paints, attractive stencil designs, which bring out in relief the color combinations, may be applied.
For the decoration of chambers and living rooms, delicate French grays, light buffs, cream tints and ivory whites may be used, while in the library and other rooms richer and more solid colors, such as greens, reds, and blues, may be harmoniously combined.
Defects of Wall Paper.It recently occurred to the writer to investigate the conditions which obtain in many apartment houses in the larger cities. Inspection of a number of such places, in which wall paper had been exclusively used on the walls, showed generally bad conditions; bulging of the surfaces, caused by dampness in the walls, which had loosened up the binder, as well as peeling and dropping of the paper from the ceilings, were frequently observed. In many cases a shabby appearance was shown, accompanied by an odor which suggested decomposition of the paste binder used on the paper. The writer was impressed with the fact that such conditions could easily be avoided by the very simple expedient of using properly manufactured wall paints, which are so easily made dustproof and waterproof.
Samples of wall paper, which had been applied to plastered walls for a year or more, were obtained, and examination under the microscope showed a most uncleanly surface. Cultures were made of these samples, and bacilli of different types were developed in the culture medium in a short time.
Experimental Evidence.That the above conditions could not have existed, had proper wall paints been used, seemed doubtless, and suggested a carefully conducted experiment to prove the relative sanitary values of wall paper and wall paints. A large sheet of fibre board, such as is occasionally used to replace plastered walls, was painted on one side with a high-grade wall paint, three-coat work. A similar sheet was papered on one side with a clean, new wall paper. These test panels were placed where unsanitary conditions, such as dampness, foul odors, and a scarcity of air were present. After a short period of exposure, the panels were taken to the bacteriological laboratory and a small section of the painted surface, about two inches square, as well as a small section of the papered surface of similar size, wereremoved and used for making cultures. In each case the surface of the section under test was washed with 100 c.c. of distilled, sterilized water. The washings which dripped from the surface were collected in a graduated flask. One c.c. of the washings was used in each case, admixed with bouillon and again with agar-agar. The enormous development of bacteria in the bouillon, treated with the washings from the wall-papered surface, was sufficient evidence to convince one of the greater sanitary value of the wall paint, the washings from which gave a culture practically free from bacteria. The colonies of bacteria shown in the petri-dish test made of the washings from wall paper further supports these findings. It will be noticed that the tests made from the washings of the wall paint show practical absence of bacteria, and was clear, as was the bouillon-solution test of the paint. The washings from the wall paper showed active development of bacteria, both in the bouillon and agar tests.
From the Conservation Standpoint: It would be of interest to sum up in figures the acreage and cordage of wood that annually is transformed into pulp for the manufacture of wall paper. Unfortunately, there are no available statistics on this subject. It is clear, however, that from the standpoint of conservation the use of wall paints should take precedence over the use of wall paper.