340 PAINTS AND PAINTING 



metal if it is not to be imbedded at once, or is not to be used in con- 

 crete-steel construction where the adhesion of the cement to the metal 

 is an essential element. When the metal is to be imbedded immediately 

 it is better not to paint it. 



Portland Cement Paint. A Portland cement paint has oeen 

 used on the High St. viaduct in Columbus, Ohio, with good results. 

 The viaduct was exposed to the fumes and blasts from locomotives, so 

 that an ordinary paint did not last more than six months even on the 

 least exposed portions. The method of mixing and applying the paint 

 is described in Engineering News, April 24th and June 5th, 1902, 

 as follows: "The surface of the metal was thoroughly cleaned with 

 wire brushes and files the bridge had been cleaned with a sand blast 

 the previous year. A thick coat of Japan drier was then applied and 

 before it had time to dry a coating was applied as follows : Apply with 

 a trowel to the minimum thickness of 1-16 inch and a maximum thick- 

 ness of Y^ inch (in extreme cases ^ inch) a mixture of 32 Ibs. Portland 

 cement, 12 Ibs. dry finely ground lead, 4 to 6 Ibs. boiled linseed oil, 2 

 to 3 Ibs. Japan drier." After a period of about two years the coating 

 was in almost perfect condition and the metal under the coating was as 

 clean as when painted. The cost of the coating including the hand 

 cleaning, materials and labor was 8 cents per square foot. 



While this method of protecting metal is somewhat expensive it 

 will certainly pay for itself in many places around smelters and shops. 



References on Paint and Painting. For a more complete dis- 

 cussion of the subject of paints the reader should consult the following: 



Iron Corrosion by Louis E. Andes. 



The Painting and Sand Blast Cleaning of Steel Bridges and Via- 

 ducts, by George W. Lilly, Engineering News, April 24th, 1902. 



Rustless Coatings of Iron and Steel, by M. P. Wood, Transactions 

 American Society of Mechanical Engineers, Vols. 15 and 16. 



Preservation of Iron Structures Exposed to the Weather, by E. 

 Gerber, Transactions American Society of Civil Engineers, May, 1895. 



Painting Iron Railway Bridges, by Walter G. Berg, Engineering 

 News, June 6, 1895. 



Paints and Varnishes, by A. H. Sabin, Association of Engineering 

 Societies, February, 1900. 



Application of Paints, Varnishes, and Enamels for the Protection 

 of Iron and Steel Structures and Hydraulic Work a pamphlet for 

 free distribution by Edward Smith & Company, New York. 



