CHAPTER V 

 THE THEORY AND PRACTICE OF SCIENTIFIC PAINT MAKING 



Laws of Paint Making. To secure a proper comprehension 

 of the composition of paints, and to be able to interpret the 

 functions of their various constituents, requires an understand- 

 ing of the general physical principles involved. The modern 

 grinder has accepted the Law of Minimum Voids, and upon this 

 law he bases the design of paint formula?, aiming toward the 

 production of what have been properly termed Scientifically 

 Prepared Paints. Perry's formulation of the Law of Minimum 

 Voids in a paint coating, and the analogy which he has drawn 

 between a scientifically prepared paint and a well-proportioned 

 concrete, was the result of genuine scientific thought following 

 observation and experimentation. It must be admitted that 

 analogies are not always safe to draw conclusions from, but it 

 surely is no fallacy in reasoning to draw analogies between these 

 two materials, when they resemble each other in so many ways. 

 To carry out processes of reasoning, and to formulate laws from 

 such close analogies, is certainly a step in the right direction. 



A graphic summary of the analogies between a properly pro- 

 portioned concrete and a paint, are shown on next page. 



Although this table graphically summarizes the principles 

 involved, the matter is presented with greater clearness in 

 the following: 



Law No. 1 The law of minimum voids to be observed in 

 constructing a paint formula this law having already been 

 accepted as mathematically correct and technically proved in 

 the technology of concrete and cement. 



Corollary The requisite thickness of a paint film together 

 with the utmost attainable strength and impermeability can 

 best be obtained by a properly proportioned blend of pigments 

 of three or more determinate sizes. 



Law No. 2 The law of the flat arch in paint coatings i.e., 

 the fact that in studying the fundamental physical principles 



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