324 PLANTS AND MAN 



them. Slack cooperage includes barrels, tubs, buckets, and 

 churns, used mostly for the shipment of dry or solid substances 

 such as flour, sugar, chemicals, powdered milk, vegetables, lime, 

 rosin, cement, fruits, hardware, and china. Tight cooperage is 

 made to contain liquids, such as wines, whiskey, beer, syrup, 

 turpentine, chemicals, and meat products. White oak, because 

 it is very hard and impermeable, yet workable, is by far the lead- 

 ing-tight cooperage wood. Due to the great demands made upon 

 white oak for this purpose, it is becoming scarce and expensive 

 to use. Substitute woods, which must be paraffined to protect 

 against leakage, include red oak, red gum, and white ash. 



Slack cooperage, which must be primarily light in weight 

 and cheap since it competes with cardboard and paper con- 

 tainers, utilizes such woods as the less desirable oaks, red, 

 tupelo, and black gums, maple, elm, ash, beech, birch, basswood, 

 Cottonwood, southern yellow pines, Douglas fir, and ponderosa 

 pine. 



Three separate processes of manufacture are required for the 

 production of the component parts of cooperage. The staves are 

 knife cut, or sawed (the latter method being preferred because 

 of reduced waste) from bolts or split short log lengths brought in 

 from the woods. They are then dried, either in kilns, or by piling 

 so as to admit free air circulation, in a drying shed. The headings 

 for barrels are built up of boards sawed from wood bolts of the 

 desired length, and the wooden hoops, 95% of which are elm, 

 are cut or sawed from planks or thick boards. In recent years, 

 metal hoops have been used in increasing quantities, displacing 

 the wooden hoops. In order to save on transportation, the three 

 parts of cooperage are very often shipped, unassembled, to the 

 point of use, where they are assembled and filled. 



Veneers and plyvs^ood. — Veneers, or thin sheets of wood, 

 have been used by man for hundreds of years. Until about fifty 

 years ago, they were made of highly ornamental woods which 

 were too expensive to be used in the form of solid boards in the 

 manufacture of furniture. In recent years, however, veneers cut 

 from inexpensive, or low grade woods have found widespread use 

 for crates, containers, baskets, trunks, battery separators, and 

 most recently plywood. The last named consists generally of three, 



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