H A R D W O O iJ RECORD 



17 



carried by special conveying machinery up one side and down the 

 other, the trip being timed to give the wood a thorough steaming 

 by the time it returns for discharging. These barrels are im- 

 mediately trussed up and then turned over a fire to dry. The heat 

 of the steam assists enough that it is only a matter of minutes to 

 turn the barrels out dry. 



There is no question that steam assists in drying; there seems 

 no question that it makes the color more uniform, but there may 

 be some question of color effect, and there is a question of pressure 

 that enters, and that might well have a thorough airing. 



The article referred to entitled "Evolution in Lumber Season- 

 ing," was published in Hardwood Eecord of April 10, and perhaps 

 did not go into details as much as it should for a thorough under- 

 standing of this important evolution in lumber seasoning, which 

 promises not only to revolutionize the entire practice of render- 

 ing lumber suitable for use, but probably marks an epoch in lum- 

 ber history of a reduction in cost between the mill and the loaded 

 car, that, depending on size of operation and conditions, will run 

 from two to four dollars a thousand feet. 



Referring to the letter above quoted. The writer is absolutely 

 right in the statement that the employment of steam under 

 pressure renders the color of oak and many other woods more uni- 

 form and also reduces the tendency of the wood to swell and 

 shrink with subsequent changing atmospheric conditions. The 

 writer 's observation that oak is materially darkened by the 

 process of steaming under pressure may be true, but it is not true 

 unless the wood is subjected to unnecessary pressure and to a much 

 longer time in the steam cylinder than should be employed in 

 proper treatment. 



Plain red oak, for example, which is a wood showing much varia- 

 tion in color, should in 4/4 thickness not be subjected to more 

 than twenty pounds pressure, and not be left in the cylinder under 

 pressure more than ten minutes. The result of this kind of treat- 

 ment will be that the color of the entire load will be very uniform 

 but will not be darkened. The wood when blown out in the air, 

 or kiln-dried will be of such a uniform tone as almost to indicate 

 that every board came out of the same tree. 



Long experience of those competent in steaming lumber under 

 pressure indicates that twenty pounds pressure is the right one to 

 attain the best results on most varieties of lumber, but that the 

 time in which the lumber is steamed should be varied from five 

 minutes t»as high as not to exceed thirty minutes in various kinds 

 and thicknesses. It must be borne in mind that the fibre of the 

 wood should not be pulped or its strength in any wise impaired by 

 the process of steaming under pressure, and twenty minutes 

 pressure for a limited time will not pulp the fibre or impair the 

 strength of the wood. As a matter of fact this process has been 

 successfully employed for more than five years by a producer of 

 the very highest type of maple flooring, a wood notorious for tak- 

 ing on objectional stain and color. The experience of this house 

 iu steaming maple has been that it has not darkened the color 

 of the wood or impaired its quality in any particular, but rather 

 the texture and working qualities have been improved. 



Steaming wood under pressure, and steaming it without pressure 

 or boiling it in water, should not be confused in the minds of any- 

 one. The writer is wrong in the statement that it is practically 

 the same thing. Steaming without pressure, or soaking wood in 

 water is a superficial process, and of necessity the outside of the 



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