Iron corrosion; anti-fouling and anti-corrosive paints . der looselyadherent to the substructure. The cracks are at least quiteas prejudicial to the preservation of the iron as the coherentbut permeable coat of paint, since they admit moisture tothe metal and engender rust, whilst the more or less absor-bent paint also takes up and retains water, and may there-fore also give rise to the formation of rust. Hence, in order toensure the preservation of the iron, the formation of cracks IRON-COREOSION AND ANTI-CORSOSIVE PAINTS. 87 must, as far as possible, be obviated by the selection of paintof a
Iron corrosion; anti-fouling and anti-corrosive paints . der looselyadherent to the substructure. The cracks are at least quiteas prejudicial to the preservation of the iron as the coherentbut permeable coat of paint, since they admit moisture tothe metal and engender rust, whilst the more or less absor-bent paint also takes up and retains water, and may there-fore also give rise to the formation of rust. Hence, in order toensure the preservation of the iron, the formation of cracks IRON-COREOSION AND ANTI-CORSOSIVE PAINTS. 87 must, as far as possible, be obviated by the selection of paintof a suitable character. When, however, cracks have oncecommenced to form, a fresh coat of paint must be laid on atonce, and this also applies to cases where the paint hasperished, a condition easily recognised by the dull earthyappearance of the coat and the ease with which it can beremoved. In this respect no difference exists between thetwo, except that a layer of weathered paint is capable oftaking up a good deal of oil or varnish, and the formation of. Pig. 40 (magnified).—Blisters, formed by warmtli, in a red lead paint poorin varnish, covering a bottom coat rich in oil. cracks is entirely precluded, whereas in the other case this isalways liable to recur. The time taken by oil paints in drying has already beenstated as from six to thirty-six, and even forty-eight hours,and depends on the drying properties of the oil or varnish,the influence exerted by the pigment, and—last, but by nomeans least—the external conditions of temperature andweather. It maj also readily happen that one and thesame paint may dry at one time in six hours, but require 88 lEON-COEEOSION AND ANTI-COREOSIVB PAINTS. at another time twelve hours and even longer. For thisdivergence the vs^armth and moisture content of the externalair are to blame, paint that normally dries in twelve hoursdrying in six hours under a hot sun and in a good draught,whilst in foggy weather it will still be wet at the end
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcorrosionandanticorr
