Waterbury evening Democrat., 1908-10-20
WOOD PRESERVATION.
Progress That Has Been Made in Re-
 cent Years.


 I Progress That Has Been Made ii, Re- cent Years.
 During the past few years greater advances have been made in methods
 of wood preservation than many peo- pie realize. Lumber users have be- come convinced that in the chemical
 treatment of timber and the conse-
 quent lengthening of the woods life
 that they can save both the great
 cost of materials and the labor in renewals. 5 Just few years ago prominent
 man, in a paper read before the Pa-
 cific Coast Railway club, called at
 tention to the pressing need of a
 thorough investigation of all pro-
 cesses used in the preservation of
 wood. At that time he deplored the fact that neither the government nor
 corporations would offer inducements
 to men competent to carry out such investigations. The particular prob lem which he had in mind was the treatment of piling to make 1t re- sistant to attacks of marine wood
 borers, such as teredo and limnoria. This problem is indeed serious one, but probably no more so than that of
 preserving ties, poles and mine tim bers against decay.
 About the same time that this pa per was presented before the Pacific Coast Railway club the United States forest service established an office, the duties of which would be to in- vestigate known conservatives and
 processes and to devise. means, if pos sible, whereby the present methods could be improved or cheapened, CT
 new methods developed to take the place of those already in use. Since its inception the office of wood pre- servation has made rapid strides. Up to the present time experiments have
 been carried on in cooperation with corporations, educational institutions and individuals to try out various theories in actual practice, and the results have proved of value not only to the co-operators, but to large
 number of people having interests similar to those to which the particu- lar experiment applied.
 Preservatiye treatment is recog-
 nized as a paying proposition wher- ever construction timber is exposed to soil or atmospheric influences
 causing decay This statement is fully attested by the rapid increase in the use of treated timber in recent
 years. The increase has been m ,st
 notable in the case of railway cross
 ties. All of the larger companies in
 the west now use. treated ties to a
 greater or less extent, and many of them operate thelf own treating plants.
 It is also notable that the use of treated timber is confined principally to corporations requiring. very large
 quantities of construction material This Is largely accounted for by ;he fact that the pressure system of im- pregnation in common use requires expensive retorts and machinery, and is not adapted to plant of small ca
 pacity, thus making it impractica5le for a concern using small or mol crate amount of timber to undertake treating.
 Besides the plants operated by corporations for the treatment of their own construction timber, there are number of plants which do a commercial business, but these being
 located at centers of distribution,
 where a permanent business is more
 readily assured, are not accessible to
 timber which goes direct from forest
 to consumer without passing through such central distribution point For economy, the treating should be con-
 ducted at point where additional
 transportation charges on account of
 the treating will be reduced to a
 minimum. The ranchman drawing
 his timber from the adjoining forest should have on the ranch the means
 for treating his fence posts and sim liar materials. The mining concern should have at the mine plant with capacity adapted to their need. An electric company whose lines extend over a considerable area and which
 draws it's timber from various sources. may find small portable plant best for treating poles.
 For several years the forest ser vice has been experimenting with a method of impregnating wood, which requires no expensive equipment, Is simple in operatioh. and is adapted to a plant of any desired capacity. It is now known that all of the more porous woods can be treated suc- cessfully by this method. The method is called the ''open tank" or "hot and cold bath process. The impregnation is accomplished by thoroughly heating the timber in a tank containing a liquid substance. then running of the hot liquid and filling the tank with cold, or transfer ring the timber from a tank coEtain- ing hot to a tank containing cold liquid, or allowing the whole to cool without change.
 The theory of the process is that the air in the wood cells and inter cellular spaces expands when heated and is partically expelled Upon cooling, it again contracts, thus cs us- ing partial vacuum, and the press ure of the air on the outside forces the liquid into the wood. The pro- cess may be applied with any of the conservatives in common use. as, for instance, creosote oil and zinc chlo- rid solution. The principle is the same whether the treating is done in small tank holding a few fence posts and heated with a wood fire underneath, or in larger tanks fitted r-- |