26 



HARDWOOD RECORD 



coast cities, it must be confessed that they know how to treat woods 

 in just as satisfactory shape as they do in the East. Wood finishers 

 of that region are really making some very handsome work out of 

 quite ordinary woods. There seems to be a growing taste for the 

 use of additional quantities of red gum, and also an increased demand 

 for mahogany and other of the finer cabinet woods. 



As a general rule, the mahogany of the Pacific coast is red birch 

 in the form of panels and ' ' battens, ' ' which is the common name of 



the finishing strips, including the parting strips between panels, 

 casings, base, etc. 



There is one thing that can be said about the Japanese oak com- 

 petition. Good authorities state that there is less than 150,000,000 

 feet of this wood remaining in Japan, and that within five years the 

 total stand will be exhausted. Only the butt cut of the tree goes 

 into hewn timber for lumber production, the remainder of the tree 

 being utilized for other purposes. 



\SiliKiaiB51i>5tf>^lW>ig OTS!aCi)^l!^^ 



Ever since lumber production became an important commercial 

 pursuit there has been but one general system employed in seasoning 

 wood, which has consisted in either cross-piling the lumber or piling 

 it on stickers, and permitting nature to extract such moisture as it 

 eould under varying conditions. Such lumber as was employed for 

 high-class purposes was then subjected to one of numberless systems 

 of kiln-drying to fit it for eventual utilization. Latterly the lumber 

 trade quite generally is awakening to a suspicion that a better system 

 of lumber seasoning can be pursued, and during a recent period more 

 than a half score of leading lumber manufacturers have installed, 

 in connection with their plants, an apparatus for steaming lumber 

 under pressure, in large quantities, for the purpose of preparing it 

 for prompter and more accurate drying. 



While steaming wood under pressure will not relieve it from log 

 stain, log checks or splits, knots or shake, users of the equipment 

 allege that there are no future defects 

 developed in drying after the wood is 

 subjected to this treatment. Further- 

 more, it is claimed that the lumber 

 dries out to a lighter weight witliout 

 cheeking or warping, to a uniform tone 

 and with a minimum of shrinkage — in 

 some instances no shrinkage at all. 



Up to this date the system of steam- 

 ing wood under pressure is employed by 

 various manufacturers of red and sap 

 gum, oak, cypress, mahogany, sycamore, 

 maple, birch and beech, and ever}' user 

 of the commercial equipment, which is 

 built to handle fifty thousand feet and 



USE 8 -lO' ORIZ' 



STO PIPE 



THO BOTH ENDS 



/ 

 LOOSE CAP 



i'PIPE DRAIN 

 upwards daily, is enthusiastic over the pLAN EXPERIMENTAL EQUIPMENT FOR TREATING 

 result'? attained. WOOD WITH STEAM UNDER PRESSURE 



The use of this apparatus has dis- 

 covered to students of lumber aflfairs how little even the highest- 

 class experts in the trade know about wood physics, wood structure, 

 wood chemistry or wood diseases. It is found that nearly every 

 variety and thickness of wood has to be treated with different 

 steam pressure and time to attain the highest results in seasoning, 

 and that woods of the same variety growing in different regions 

 have to be handled slightly differently to accomplish tliis end. 



There is nothing new in either the theory or practice of treating 

 wood with steam, either with or without pressure, but within a 

 recent time a commercial apparatus has been devised which renders it 

 possible to treat wood with steam under pressure at a nominal cost 

 and secure remarkably satisfactory seasoning results. Superficial 

 steam applied to wood, either in a dry-kiln or without, certainly 

 assists in the seasoning process, and contributes to the freedom 

 with which certain classes of wood can be bent into form, but it is 

 only with a scientific process that results desired are attainable. 



The attainment desired in seasoning lumber is comparatively 

 simple. It is generally known that all the value green wood has for 

 lumber purposes is its fiber or cellulose, and what is being attempted 

 in drying is to drain or evaporate the twenty-five to sixty-five per cent 

 nf the liquids or semi-liquids that are contained in the wood fiber 

 and in the cellular structure of the wood. This liquid, made up of 

 Tarious constituents, including tannic acid, albumen, sugar and starch, 



and other substances in solution and semi- solution, is to the extent of 

 about one-half contained in the wood fiber itself and the other one- 

 half is enclosed within the cells and ducts of the wood. 



In ordinary practice of drying lumber, when it is put in eross-pile 

 with the proper slope for drainage, the moisture contained in the 

 fiber drains and evaporates quite promptly, but the water contained 

 within the cellular structure of necessity has to evaporate through 

 the walls of the cells before the lumber even approximates dryness. 

 Giving wood steam under pressure simply induces an explosion or 

 slitting of the cell structure, and thus releases the liquid contents 

 for prompt drainage and evaporation. Unless this steaming treat- 

 ment is done on a scientific basis there are certain dangers involved 

 in its employment, the chief one of which is giving the wood so much 

 steam pressure and time as to pulp or injure the wood fiber, and con- 

 sequently impair the strength of the lumber. Excessive steam 

 pressure is also likely to release to too 

 great an extent the tannic acid con- 

 tained in the wood, which undeniably 

 contributes to the durability of the 

 wood. An excess of steam pressure and 

 time would also change the tone and 

 color of the wood to an extent that 

 might not be desirable, and carried to 

 au extreme would vulcanize the wood, 

 changing oak, for example, to a very 

 dark brown tone. 



On the contrary, superficial steaming 

 without pressure may simply assist in 

 breaking the cellular structure on the 

 outside of the lumber, but by no pos- 

 sible chance can it penetrate to the 

 center of the piece without an excess 

 of steaming on the outside; that is, the 

 piece of lumber can not be steamed with superficial steam and obtain 

 uniformity throughout the boards or plank. Hence, in drying this 

 kind of lumber the quality of the outer section is impaired and the 

 core of the board is unsteamcd or insuiiiciently steamed, with the 

 result that it is very difiicult to season the wood without checking 

 and often honey-combing. 



As before noted, every wood of every thickness, or every thickness 

 of every wood must be treated somewhat differently to attain the 

 highest results in prompt and accurate seasoning. 



There is a cheap and low-cost experiment which should interest 

 every lumber 'manufacturer in the country, whether he be a producer 

 of hardwoods or softwoods, that is herewith suggested and illustrated. 

 The equipment consists of a section of standard pipe, say eight 

 feet long, threaded and closed with a cap at both ends. This pipe 

 may be eight, ten or twelve inches in diameter, but the latter dimen- 

 sion is commended for experimental purposes. One cap should be 

 fixed and the other left loose and removable. To this section of pipe 

 a half-inch inlet pipe from a steam boiler should be attached, to- 

 gether with a gauge, and on the bottom a half-inch drainage pipe 

 should be attached. 



To carefully analyze the results attainable in prompt and accurate 

 seasoning, it is suggested that boards of one variety and of one 

 thickness be weighed, carefully measured and then cut in halves. 



