CLAMPS AND PRESSES
After gluing, the work should be kept under pressure for a sufficient length of time to insure perfect adhesion. In the case of hide glues the time required is from three to four hours. The time varies with variations in the glue, in condition of stock, and in temperature of room. No general statement can be made to cover the case; experience is the best guide. Either retaining clamps or presses are used.
Pressure should be distributed as evenly as possible. Presses may be had in almost every style for every need—open on one side, or on two sides; for veneered stock; sectional presses; etc. Very excellent presses are being made of structural steel. They are practically indestructible, very efficient, and yet simple in operation.
In selecting a veneer press equipment the amount of pressure per square inch must first be determined. Opinion varies with different manufacturers, some using 100 pounds, some 200 pounds, per square inch. The best general results are obtained by using 150 pounds per square inch. All presses made with a 2-inch screw should be designed to withstand a pressure of 8 tons or 16,000 pounds per screw. To find the tonnage of press that you require, multiply the length by the width of stock, this by the pressure per inch you desire and divide the results by 2,000. This will equal the tons pressure required. The number of screws per press can then be determined.