HARDWOOD RECORD 



ki 



Just aftiT 

 placing in 

 Section II. 

 At 1 p. m. At 5 p. m. 



Temperature near roof, west side 126° 127° 



Temperature lialfway up, west sitle 124° 129° 



Temperature under spray chamljer, west side 112° 123° 



(dew point) 



CalcuI.Tted humidify, west side 71% 83% 



Humidity l)y hair hygrometer, east side 60% 72% 



The manner of piling received special attention, as it is of great 

 importance. For good drying, uniform circulation of air is essential 

 so that both faces of the boards .shall dry uniformly. Edge piling 

 gives the best possible result, but it is difficult to perform, and the 

 tracks were not suited to this kind of piling. Therefore, the next 

 best thing was adopted. A wooden frame was set on the trucks with 



E.\D VIEWS OF SHRINKAGE SI'IH'I.MENS. THESE WEItE AI.I> 

 ORIGIN. \I,LY THE SA.ME WIDTH. SI INCHES. 



sloping rafters like an inverted roof or letter V. The rafters were 

 spaced eighteen inches apart, with a slope of less than tliirty degrees. 

 The boards were carefully laid, nsing 1% by % inch stickers, edge- 

 wise, and eighteen inches apart. Spaces were left between the boards 

 in each layer. In tlie center of the pile an open, tent-shaped space 

 was formed, the top of the pile being closed all the way across. The 

 first layer of boards at the lowest point was about thirty inches above 

 the steam coils. The boards were weighted by a number of partially 

 dried planks. 



Sample sections three feet long were cut from one board of each 

 lot, and also moisture discs. From the moisture determinations of 

 these discs the dry weights of the samples were calculated. By weigh- 

 ing the samples daily the rate at which the drying was proceeding 

 was kept track of. These samples were placed in the loads the same 

 as the rest of the boards, about halfway up the pile, a gap having 

 been provided for them. The original moisture contents, in per cent 

 of oven dry weight, when put into the kiln were as follows: 



Sample S, quarter-sawed 87.0 per cent; sample W, quarter-sawed, 

 S4.8 per cent; sample A, slab-sawed, 98.1 per cent. 



The drying was begun at a temperature less than 130° and a 

 humidity about ninety per cent. Throughout the experiment the 

 same conditions were maintained at night as during the day. No 

 free steam was allowed to escape into the kiln. The air circulation 

 was about 200 cubic feet per minute for every foot length of the 

 kiln. 



The wood began to shrink almost at once, and in three days' time 

 corrugations on the surface were decidedly evident. At that time 



the samples showed the following moisture content: Sample S, 76 

 per cent; AV, 72 per cent; A, 84 per cent. 



As the wood became drier the humidity was gradually decreased 

 and the temperature raised, in order to keep up a fairly uniform rate 

 of drying, until at the end of the operation the temperature readings 

 were 160° on the west and 170° on the east side of the kiln. In 

 twenty-seven days the wood was ready to take out. . 



The lumber had been dried with little or no honeycombing or cheek- 

 ing. It had greatly shrunken in every case, chiefly in the circum- 

 ferential direction of the ring. The shrinkage was very uneven, 

 alternating in amount with the alternate bands of light and dense 

 wood, the lightwood shrinking most. This gave rise to a very curious 

 corrugating of the surface of all quarter-sawed boards, the corruga- 

 tions running lengthwise, and as deep as the corrugations in an ordi- 

 nary washboard. The quarter-sawed boards remained flat. The slab, 

 cuts, however, .were generally warped, the heartwood portion bending 

 outward, but the sapwood portion, strange to say, in tlie reverse direc- 

 tion, so that a slab-cut board, containing heartwood in the central 

 portion and sapwood on the edges, bent with double curvature, the 

 cross section resembling a flying bird in outline. 



Many of the boards were wavy in the lengthwise direction. Closer 

 spacing of stickers would have helped this condition somew-hat. 



The average moisture content of the lumber taken from the kiln, 

 as determined by thirteen- -samples, was slightlj' over 8.5 per cent, 

 varying from 6.2 to 11.8 per cent. 



In regard to the three kinds of treatment, there appears to be vety 

 little choice. If anything, it appears that the wood previously boiled 

 in water was bent more than the others. In fact, the wood which 

 was placed in the kiln directly without previous treatment was in as 



(■(.l.MrAIUSON OF KILN-DRIED SA.MPLE A 110 WITH (lUIGINAI, WET 

 BOARD FROM WHICH IT WAS SAWED. 



good shape as any. Steaming and boiling appear to soften up the 

 blue gum so that it does not hold its shape so well. 



In order to give some idea of the proportional amount of lumber 

 from this selected material which would finish up into at least half- 

 inch boards of three feet or more in length, the boards were sorted 

 and weighed. The proportion of good boards in any one of the three 

 treatments depended more upon the number of radially-cut boards 

 included, than upon any difference observable due to treatment. No 

 significance, therefore, can be jilaced upon the relative amounts of 

 good and bad as between the three treatments. The whole lot weighed 

 1,885 pounds — good boards, A 365, S 340, W 170, total 875 pounds; 

 poor, due to warping, A 415, S 175, W 420, total 1,010 pounds. The 



