GLAZING AND PAINTING 105 



Putty purchased from dealers in green- 

 house supplies will not need the addition of 

 lead. It should be worked as soft as it can 

 be handled in order that it may be easily 

 forced into all cracks and crevices. It is 

 applied with a putty knife or with a putty 

 machine. The putty machine distributes the 

 putty rather more rapidly than can be done 

 by hand, but it is necessary to use a putty 

 knife in conjunction with it. 



Setting the Glass. The basic difference 

 between glazing greenhouse roofs and glaz- 

 ing ordinary window-sash is in the method 

 of applying the putty. In glazing window- 

 sash, the putty is placed on the outside. In 

 greenhouse glazing the putty is placed in the 



i 



A. 



Fig. 60. A, window glazing; B, greenhouse glazing 

 The putty is shown at a and b 



grooves in the bars and the glass is forced 

 into it. That which oozes up around the 

 edges is scraped off and used again. By this 

 method, little putty is exposed to the air, but 



