﻿KILN DRYING HANDBOOK. 



41 



WALNUT GUNSTOCKS. 



Walnut for mm stocks is usually cut in the form of rough blanks, 

 steamed to darken the sapwood, and then shipped to the gunmaker 

 for drying. All stocks to be kiln dried should be end dipped in 

 hot pitch before loading into the kiln. A schedule that has been 

 used successfully in the drying of many thousand blanks is given 

 in Table 12. 



MAPLE SHOE-LAST BLOCKS. 



Maple shoe-last blocks, end dipped and piled on stickers, can be 

 dried successfully under hardwood schedule 7. 



PENCIL CEDAR. 



Pencil cedar, the southern juniper used for pencils and cedar 

 chests, is quite difficult to dry and care must be used to prevent 

 the shelling off of the streaks of sapwood which will result from 

 too steep a moisture gradient and too severe casehardening. A 

 special schedule (Table 13) has been prepared for the drying of 

 1-inch boards of this species; it covers about the same range as 

 hardwood schedule 3. 



The cedar oil present in this wood causes a variable error in 

 making moisture determinations, since it is driven off with the 

 moisture in the drying oven, resulting in a calculated moisture con- 

 tent higher than the actual. This error is usually not more than 

 2 or 3 per cent, though it may be as great as 5 per cent. 



Table 12. — Drying schedule for Made walnut gunstock blanks. 



Moisture 

 content. 



Dry bulb. 



Wet bulb. 



Relative 

 humidity. 



Per cent. 

 Initial. 

 35 

 20 

 15 

 10 



8 to final. 



°F. 

 110 

 113 

 115 

 117 

 130 

 140 



°F. 

 102 

 102 

 104 

 103 

 105 

 107 



Per cent. 

 75 

 68 

 67 

 62 

 43 

 34 



Table 13. — Drying schedule for 1-inch pencil cedar, 



Moisture 



content 



(heart 



samples). 



Dry bulb. 



Wet bulb. 



Relative 

 "muuidity. 



Per cent. 

 Initial. 

 20 

 15 



10 to final. 



°F. 

 140 

 150 

 155 



160 



°F. 

 128 

 127 

 124 

 115 



Per cent. 

 70 

 50 

 40 

 25 



PLYWOOD PANELS. 



The drying of plywood panels is a special problem in which sim- 

 plicity of control and operation are important. Panels can be dried 

 successfully under widely varying conditions of temperature and 



