Kleb's Custom Board Building: Shaping

• Measure a board:
  • width
  • thickness [calipers]
  • mastbox, finbox, strap placement
  • rails [contour gauge]
  • rocker [pieced together plywood or masonite]
• Buy an appropriate blank. Clark will make custom blanks on request, tweaking rockers, etc.

  

• Get into your "really careful mode" since from now until you laminate both sides of the blank you will have a very fragile foam blank sitting around just waiting to be ruined by the slightest bump, etc.
• Use electric planer, a surform, or a sanding block to remove the bottom "skin"---about 1/16".

  

  Then plane/sand/hand-plane bottom rocker to shape.
• Spline-sand bottom flat using a 3 foot long sanding block with 3 pieces of 9" x 11" 40 grit sandpaper glued to the bottom. To check your sanding progress use low light and shin a small lamp for the sides and ends to check for waviness. Also check for twist by sighting the tops of two straight blocks set a few feet apart, perpendicular to the centerline of the board.
  
• Hand-plane stringer(s) to match foam. (The stringers will be slightly raised since they are much harder than the foam.)

  

• Make a spin template from thin plywood or masonite by connecting the width measurements with a metal ruler held on edge so that you can bend it to create a smooth shape for the front and back halves of the board.
• Trace planform from spin template.

  

• Cut the foam slightly outside of the line with hand saw or electric planer. Use a sanding block to carefully remove the rest of the foam.

  

• Now lightly mark the measurement stations along the bottom and draw lines perpendicular to the centerline and up the sides. At each measurement station mark the thickness, connect the marks, and plane and/or sand to the proper thickness.
• Shape the rails. This is the scary part. Either you know what your doing or you cheat. Cheating is done by making rail profile templates from the contour gauge measurements that you took from the board that you are copying.

  

  (You can get the raw data for this plot if you so desire.)
• I glued the profiles onto a piece of scrape countertop laminate with 3M Spray Adhesive #77 and cut them out on a small bandsaw.

  

• Then, using these as guides, I picked a side; and starting at the tail, worked toward the nose using a 12" sanding block with 40 grit sandpaper and the electric hand planer. An open-faced, rasp called a Surform also works well for this step.

  

• Finish sand the blank with 220 grit sand paper. Using a sanding screen (typically used by drywall installers) works well on the rails.
• If you have any areas with sharp rails, they must be rounded to at least a 3/16" radius. Otherwise the glass will not be able to wrap around them without lifting off the foam, creating both unsightly air bubbles and an entirely wrong rail shape. The sharp edges will be added later.