a ea 
KILN DRYING HANDBOOK 61 
WALNUT GUNSTOCKS 
Walnut for gunstocks is usually cut in the form of rough blanks, 
is steamed to darken the sapwood, and is then shipped to the gun- 
maker for drying. All gunstocks to be kiln dried should be end- 
coated before they are loaded into the kiln, preferably with 213° 
coal-tar pitch or filled hardened gloss oil. A schedule that has been 
used successfully in the drying of many thousand blanks is given in 
Table 23. 
TABLE 23.—NSpecial kiln-drying Schedule 118 for black walnut gunstock blanks 
Dry- Wet- 
bulb bulb Relative 
Moisture content at which changes should be made, per cent temper- | temper- | humidity 
ature ature 
Sh Ja ole Per cent 
AD) OSE TOGO PE Ds cco NS REI SLU aS GA et Ra a LE A US ie a ie 
Pi epee sia AL RS I CS SRE A at NOP ge Ni A LO A UO aE AD es a) 
PQ) ase cet TE a ge al AS SU Yeap AC A AP ag OE 115 103 66 
TUB ay EI A VI RR SEO RAL La ea gh av Ne UE UR 117 103 62 
i) aR RC epee pe URN Nod Alene Livni upd ALAR IRL CLS AEE SNC AU GLO a MIU Be 130 105 43 
C3 GO) THA Le SEI SH ate ES SUS af QDR ae OS Ca LEO 140 107 34 
Steaming walnut to darken the sapwood is usually done in steam 
boxes, which are chambers adapted to the use of steam at atmospheric 
pressure. It is customary to steam 1-inch stock about four to five 
days at a temperature of 140° to 160° F. Either live steam or ex- 
haust steam may be used. 
Steam boxes and patent steaming cylinders are discussed inciden- 
tally on page 66. 
MAPLE SHOE-LAST BLOCKS 
Maple shoe-last blocks, end dipped and piled on stickers, can be 
dried successfully under hardwood Schedule 7 of Table 2. 
BENT STOCK 
Bent stock of various kinds may be dried according to the lum- 
ber schedules applying to the species of wood and the thickness of 
piece, but, as with oak wheel rims, steaming must be done with 
caution, since the excessive use of steam in the early stages of such 
drying is very likely to result in the loss of the bends in the stock. 
PLYWOOD PANELS 
The drying of plywood panels after they have been glued is a 
special problem in which simplicity of control and of operation are 
important. Although such panels can be dried successfully under 
widely varying conditions of temperature and of humidity, the ef- 
fect of the drying schedule upon the strength of joint may well 
be considered. It has been found possible to dry panel stock satis- 
factorily at a constant temperature and a constant humidity corre- 
sponding to a moisture content about 2 per cent below that which 
the panels are to reach. Thus, if the panels are to come down to 
10 per cent, a humidity corresponding to about 8 per cent moisture 
