~ COLLEGE OF AGRICULTURE COOPERATIVE EXTENSION SOOVICE WASHINGTON STATE UNIVERSITY PULLMAN, WASHINGTON 99163 January, 196 7 E«!M() 2753 lVHITEWASH AND ITS USE There are probably as many methods of making whitewash as there are uses for ito The principal ingredient in whitewash is lime pasteo A satis­ factory paste can be made with hydrated limej but better results are obtained by using quicklime that has been slaked with enough water to make a moderately stiff paste and has been kept in a loosely covered container for several days, or preferably monthso Eight gallons of stiff lime paste are produced by slaking 25 lbso of quicklime in 10 galso of water or by soaking 50 lbso of hydrated lime in 6 galso of watero The paste should then be strained through a fine screen to remove lumps or foreign mattero If casein, t risodium phosphate~ or formaldehyde are not r eadily obtainable, casein glue may be substituted f or these three ingredient s in the propor­ tion of 5 lbso of casein glue to 8 galso of lime pasteo The casein glue should be dissolved in water according to manufacturer 0s directions, diluted to a thin consistency~ and mixed thoroughly with the lime paste just before usingo Do not make more of this mixture than can be used in one day, as it may deteriorateo Casein glue may be obtained in most paint and hardware storeso The inability to obtain casein f or use in any of the formulas where it is recommended also can be compensated for, in part at l east, by substituting skimmed milk f or the water o Skimmed milk contains approximately 3 percent casein, and therefore its use as t he vehicle introduces about three~fifths of the amount of casein ordinarily suggestedo In this conn ection~ it· is preferable to make the lime paste hydrated lime rather than quicklime, as the heat produced by slaking quicklime with skimmed milk may cause the separation of i nsoluble compoundso One of the simplest methods for preparing whitewash requires 15 pounds of salt and eight gallons of lime pasteo Dissolve the salt in about five gal­ lons of water; add this solution to the lime pasteo Mix thoroughly and thin to the desired consistency with fresh watero Another easy method requires 25 pounds of dr,y white portland cement and the same amount of dry hydrated lime o Add both together to ei ght gallons of water o A thick slurry will be obtained by mixing thoroughly o Additional water with further agitation wil l result in a mixture resembling a heavy creamo Do not rrdx more than can be used in a few hourso EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS IN COOPERATION WITH U.S. DEPARTMENT OF AGRICULTURE )! EoMo 2153 ~ Page 2 other Formulas Salt - 12 lbso~ Alum (powdered) ~ 6 ozo, Molasses ~ 1 qt.~ Lime Paste~a 8 gals. This formula produces a whitewash that has a yellow tinge when first applied but the color disappears in a few days and a ver.y white, durable coating resultso Dissolve the salt and alum in 4 gals. of hot water and then add the molasseso Add the clear solution to the lime paste, stirring vigo~ously~ and then thin to the desired consistency. Casein - 5 lbso~ Trisodium Phosphate ~ 3 lbs., Formaldehyde - 3 ptso~ Lime· Paste - 8 galso This formula is recommended for most uses as the coating is white~ does not rub or chalk~ and is quite W€ather-resistant. Borax may be substituted for the trisodium phosphate but these mixes are not quite as durableo Soak the casein in about 2 galso of hot water until thoroughly softened (about two hours). Dissolve the trisodium phosphate in 1 galo of water~ add this solution to the casein and allow the mixture to dissolveo Dissolve the formaldehyde in 3 gals. of watero When the lime pasti and the casein solution al'e thoroughly cool, slow1y add the caSe'in so ution to~ lime!) stirJr~constantl;:- -- Just before using~ slowly add the formaldehyde solution to ·the batch, stir­ ring constantly and vigorously o Care must be taken not to add the formalde­ hyde too rapidly as this may cause the casein to form a jel~-like mass, thus spoiling the batcho Do not make up more of this formula than can be used in one day~ as it may deteriorateG Disinfectant whitewash ~ For a mild disinfectant or insecticidial white­ wash, add a quart of crude carbolic acid to the whitewash obtained by slaking half a bushel (25 pounds) of quicklime or by mixing a sack (50 pounds) of good hydrated lime with watero For a strong germicidal whitewash, add 2 quarts of crude carbolic acid to the whitewash. Disinfectant whitewash~ small quantity - Dilute 1~ quarts of commercial lime-sulphur with about 3 gallons of water and add three tablespoons of common salt, previously dissolved in a pint of water.o To this solution add, while stirring constantly~ a lime cream made by mixing a heaping quart of good hydrated lime with water (or by slaking about ~~pounds of fresh quicklime and straining through wire f~ screen)o Recommended Colors for Whitewash - There are three factors to be considered in connection with colors used to tint whitewash and cold-water paints: first, that they shall not react chemically with the lime; second, they shall be insoluble in water; third, E.MQ 2753 - Page 3 the mixing shall be as nearly perfect as possibleo The following pigments may be purchased as dr.y powders and added to any of the whitewash formulas listed in this pamphlet. The amount of pigment necessary will depend upon the shade of color desiredo To be sure that the desired shade will be obtained, it is always advisable to prepare a small sample and allow it to dr,y before mixing any considerable quantity. Blacks - Magnetic black oxide of iron is safe. Ivory black and carbon black are non-reactive with lime, but they are lacking in strength. Blues - Ultramarine and cobalt blue are the only blues recommended. Browns - Pure precipitated brown oxide of iron or mixtures of the magnetic black oxide of iron with turkey or Indian red are high~ recommendedo Sienna and turkey umber are lacking in strength, but may give good results. Greens - Chrqmium oxide (opaque) or chromium oxide (hydrated) are recommended. These are known as chromium or chrome oxide greens and should not be con­ fused with mixtures of chrome yellow and Prussian blue, known as chrome greens, which are not lime-proofo Reds - Indian red made from pure ferric oxide is high~ recommended. Madder lake and toluidine vermillion are alkali fast, but have little strength and are fugitive to light. Violets - Cobalt violet and mixtures of the reds, whites and blues suggested are satisfactory. Whites - Lime itself is satisfactory, Lithopone and ground marble also are used as white pigments. Yell~~s- Those made by using precipitated hydrated iron oxides· are most satisfactory. Ochre, raw sienna, lemon cadmium, orange cadmium, and golden cadmium are less suitable, as they may change in shade, lack strength, or be affected by light. Chrome yellow is not lime proof. cls 1-67 .