A Continuous Method of Scarf Jointing Plywood Panels

Continuous plywood panels, 4 feet wide, are manufactured by scarf jointing standard panels sawed 98 or 99 inches long, curing in a radio-frequency press and sizing with a traveling cut-off saw. Objectives of operation are: 1) perfect glue bond, 2) straight, long panels, 3) unlimited length, 4) minimum cost for labor and materials. Scarfs are cut (1/4-inch panel – 12:1; 3/4-inch panel – 8:1) on Globe Scarfer with 14 inch diameter, carbide-tipped, cutter-head at 4000 RPM. Melamine glue is applied by hand. Panels are precisely aligned on a steel feed table with rolling straight edge. Limit switches govern press operation to assure accuracy of alignment. They are indexed with short copper staples. Joints are pressed (1/4 inch – 45 seconds; 3/8 inch – 1 minute; 3/4 inch – 1 minute, 35 seconds) in a Model 400, 26KW, 12 by- 60 inch platen, Mann-Russel press. Platens absorb enough RF load to cure featheredge by retained heat. Panels are sanded in a Solem 8-drum double deck sander, specially designed to handle endless panels. Patches are hand set with heat and pressure. Panels are sized to nearest 1/16-inch in length. Principal uses are for boat hull construction, roof trusses, beams, and special concrete forms. An unusual bow-string truss utilizes the long panel for the top chord and the roof sub-surface. In one application, a 60-foot truss carried an ultimate load of 96.3 lbs. per square foot with a 13/16-inch panel.. One panel 163 feet in length was manufactured and shipped on three 50-foot flat cars.

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