Plywood board for concrete form edges

Abstract

A reusable laminated plywood board, specifically engineered for forming the edges of poured concrete slabs and tilt-up walls, uses in each layer a patchwork quadrangular sheets made of solid fragments of a wood species characterized by a high strength-to-weight ratio.

1 . A plywood board for use in edging poured concrete forms, which comprises: 
 first and second laminated layers, each of said layers including a patchwork of sheets peripherally connected to one another by finger-joints.    
   
   
       2 . The board of  claim 1  wherein each of said sheets consists of a solid fragment of wood.  
   
   
       3 . The board of  claim 1  wherein said wood consist of a sole species.  
   
   
       4 . The board of  claim 3  wherein said species is selected from a group consisting essentially of wood species having a strength-to-weight ratio, s/g of at least 1.000 
 wherein s is expressed in kilograms by cubic inch and g is the specific gravity defined as the oven-dry weight over the green volume.    
   
   
       5 . The board of  claim 1  wherein said species consists of  Paulownia  wood.  
   
   
       6 . The board of  claim 4  which further comprises a water repellant adhesive bonding said layers.  
   
   
       7 . The board of  claim 4  which further comprises an emulsion PVAc exterior adhesive joining said sheets.  
   
   
       8 . The board of  claim 1  wherein said sheets have grains running in a common direction.  
   
   
       9 . The board of  claim 8  which further comprises a third of said layers sandwiched between said first and second layers.  
   
   
       10 . The board of  claim 9  wherein sheets in said third layers have grains running orthogonally to said common direction.  
   
   
       11 . The board of  claim 10  which further comprises a water-repellent adhesive joining said layers.  
   
   
       12 . The board of  claim 1  wherein said sheets are quadrangular.  
   
   
       13 . The board of  claim 12  wherein said sheets have various sizes.  
   
   
       14 . The board of  claim 1  wherein said sheets are arranged in latitudinal rows of sheets having equal lengths.  
   
   
       15 . The board of  claim 14  wherein said rows in said first sheet are not aligned with rows in said second sheet.  
   
   
       16 . The board of  claim 10  wherein said sheets are arranged in longitudinal columns of sheets having the same widths.