Gluing of Furniture Parts

To sucessfully glue furniture, many factors have to be controlled. In the Drexel Furniture Co. plants, all employees involved with gluing attend training programs on the subject, followed by on-the-job training by supervisory personnel. Lumber moisture contents are held in the range of 6 to 9 percent. Material that will be glued by RF must be about 6 percent. Carbide-tipped saws have eliminated the glue jointer in most operations. Stock for laminating is surfaced either by a moulder or a finish planer. Gluing is done as soon as possible after machining because changes in moisture content can destroy the perfect joints that have been prepared. Animal glue is used for case and chair assembly, inlaying, drawer assembly, and glue blocking, with urea-formaldehyde glue being used for all other operations. Several types of radio-frequency edge-gluing machines are used. The favored one has strip-type electrodes top and bottom and 2000 RF peak volts per inch. All lumber cores are conditioned prior to finish planing to minimize the danger of sunken joints and warping. No matter what glue is used the moisture content must become uniform throughout before planing. One plant has been equipped with RF presses for all subassembly work. They are air-operated and powered with 2 and 5 kilowatt generators. When bad bends occur in RF gluing, they can usually be attributed to poor machining, excessively high temperatures, or the premature application of RF power. The most satisfactory core for plastic laminates is Douglas-fir faced with 1/16-inch-thick mahogany or soft pine. Cold pressing at room temperature is recommended because heating may cause crazing of the laminate as well as warping of the panel. The favored laminating glue is a rich mix of urea-formaldehyde resin. Pressures must not be over 50 psi to prevent transferring of panel defects to the laminate. A well-staffed testing laboratory evaluates the resin glues used. The glue room foremen still rely on the knife test to determine glue bonding quality. No other way has been found to give a fast indication of the bonding quality. However, standard tests are conducted for evaluation of the finished glue joints.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member