WOOD-FINISHING AND PAINTING 101 



as a rule; they are frequently left unprotected. Moisture, 

 air and temperature are natural weather elements which per- 

 mit the development of fungus growths which cause rot and 

 decay. All wooden structures exposed to the weather should, 

 therefore, be protected. 



Toxic mineral salts or coal-tar creosote oil is used to protect 

 outside woodwork which it is not desirable to decorate as the 

 common stains and paints do. Coal-tar creosote oil eradicates 

 fungus organisms or suspends their destructive growth. It is 

 insoluble and, therefore, is impervious to moisture. Present 

 practical results of treating wood with it have justified its use. 



The two general methods of treatment are known as the 

 pressure processes and the non-pressure processes. The for- 

 mer are used extensively by large corporations, and the latter 

 by small consumers, in which class the farmer would be 

 placed. Of the non- pressure processes, there are two, viz., 

 the open-tank system and the brush method. 



88. The Brush Method is the one which the conditions 

 of the average farm make entirely possible. It consists of 

 painting refined coal-tar creosote oil, heated to approxi- 

 mately 150 degrees F., on the wood in the same manner as is 

 done with paint, or pouring the heated creosote over the lum- 

 ber, catching the drippings in pans or basins, or applying the 

 heated creosote with a mop instead of a brush. It is current 

 opinion that in order to make effective the use of coal-tar cre- 

 osote oil, it must be applied under pressure ; nevertheless, the 

 fact remains that the brush method of surface treatment re- 

 sults in a most surprising increase in the life of the material 

 treated, and in a most satisfactory reduction in the annual 

 cost of maintenance of structure. 



