In the past, when high quality peeler logs were more plentiful it was possible to obtain plies of considerable size. With the recent growth in the industry it has been necessary to use peeler logs of lower quality from which knots must be removed from the laminates after peeling. This gives rise to a large number of pieces to be handled and glued, each as long as either the width or length of the finished plywood and upwards of 4 inches in width. Handling a large number of these small, thin pieces, only 1/24" to 3/16" thick, is exceedingly laborious and the resulting plywood is of lower quality and value due to gaps at the edges even though the knots are reduced to a minimum.
An improvement of plywood quality results and handling costs are reduced by the use of the machines illustrated, both of which incorporate Chromalox Electric Far-Infrared Heaters which deliver the heat required to dry the glue at the edges of the lamination, resulting in a single large sheet made of many small, narrow pieces glued together at their edges. In the machine at the left, Radiant Heaters are used lengthwise over the work and in the photo at the right the Radiant Heaters are used across the work.
A special form of a chemical glue is used, the plies are automatically lined up by the machine and their edges forced closely together. Machine speeds of 30 feet per minute and higher are possible but allied operations restrict the maximum speed to that indicated.
The machines use up to 72 kw. of electric heat and with this capacity are also capable of edge-gluing lumber up to 3/4" thick. Machines are made to handle ply widths of 4, 8, and 10 feet.
- Its extreme ease of control
- The rugged, all-metal construction of the radiant heat source.
- Its ability to operate in ambient temperatures of 500 ° F.