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BULLETIN 1037, V. S, DEPAKTMEI^T OF AGRICULTURE. 



STEAMING GREEN STOCK AS A CONTROL MEASURE. 



METHODS COMMERCIALLY EMPLOYED. 



Steaming certain kinds of stock (green gum lumber, birch hubs, 

 spokes, and sawed felloes of red or white oak) is sometimes resorted 

 to as a means of reducing shipping weight by hastening drying or 

 to even up the color and reveal defects in the wood. 



In the steaming of green gum lumber a large steel tank, or pre- 

 parator, is employed. The lumber loaded upon trucks is run into 

 this preparator and steamed for perhaps 15 to 30 minutes at pres- 

 sures of 20 to 30 pounds (figs. 13 and 14). Provided this lumber is 



then carefully open 

 piled, it remains clean. 

 When close piled or 

 when exposed to ad- 

 verse weather condi- 

 tions, however, it ma.y 

 mold almost as readily 

 as untreated green 

 lumber. 



Hubs, sawed felloes, 

 and turned spokes 

 green from the saw are 

 sometimes steamed at 

 atmospheric pressure. 

 At one plant visited, 

 green birch hubs were 

 stacked in large cement 

 boxes and subjected to 

 exhaust steam for 24 

 to 36 hours, depending 

 upon the size of the 

 hub. At the end of that time the steam was shut off and the hubs 

 were allowed to cool for perhaps 10 hours. The hubs were then 

 carried to a ventilated warehouse and stacked, zigzag fashion, to 

 provide for ample circulation of tlie air through the inside as well 

 as around them. In this manner an even drying was secured. Two 

 to three weeks was considered a sufficient length of time for the 

 necessary air drying previous to shipping. During the warmer 

 months, stock cars were used as means of transportation. 



The steaming of gum and birch is a comparativelj" simple process. 

 But in the case of woods that check readily, such as oak, this treat- 

 ment requires considerable care. 



Fig. 9. — A box car loaded with split billots upon its 

 arrival at thie spoke mill. The method of loosely 

 boarding the doorway, as shown in figure 8, is prefer- 

 able in that there is less danger of the stock working 

 out while in transit. When, however, the masses of 

 billets are held in position by supports, or when ver- 

 tical boards are nailed a few inches back of the cleats, 

 this method may be used. Both provide for the venti- 

 lation of the stock. 



