How To's:

Arches (bendable lauan):

1. This type board is used on an arch window or eyebrow arch window. (An eyebrow arch is shown in this example.)
2. Lauan is a plywood type board & can be special ordered from your local lumber yard, or check your local home improvement stores. Bendable lauan is available in a 4 x 8 sheet and in ¼" & 3/8" thickness.
3. To splice bendable lauan: For large arches, butt two strips of lauan together & glue with wood glue, then use 3/8" staples on front and back to secure joint. (see dia. 1)
    
   
    
4. Cut a face board from 3/8" plywood 5" or 6" wide in the shape of arch. (see dia. 2)
    
   
   
    
   
    
5. Cut the 3/8" bendable lauan the size of return needed for the treatment & length needed to curve around the arch.
6. Use 1½" nails, 1 3/8" staples or screws to secure shaped plywood to bendable lauan. (A brad nailer or staple gun can be used.)
7. Cover plywood face with blackout lining. Cover inside area of bendable lauan with straight strips of blackout lining.
8. Attach the treatment to the bendable lauan. Use gimp to cover all inside edges.
9. Cover top of bendable lauan with face fabric. Add a layer of interlining under the face fabric cover to soften edges of the mounted treatment. Welting can be added to edge of arch. Edges of face fabric should be turned under & pressed, then glued to top of arch.
10. If treatment is heavy, 1 x 2 or 1 x 4 blocks can be used along the inside of the arch to add strength.

Arches (kerfing):

1. Kerfing is the process of making evenly spaced cuts in a piece of wood to make it bendable. Kerfing is used on arch windows or eyebrow arch windows. (An arch is shown in this example.)
2. Kerfing is done by making cuts in the wood with a saw blade. The more severe the radius, the closer the cuts in the wood. The saw blade cuts are within 3/16" of cutting through the board. (see dia. 1 & 2 - dia. 2 has been enlarged to show kerfing)
    
   
    
3. The spacing between kerfs on eyebrow arches are even further apart than a regular arch.
   1. 40" arch window & under, space kerfing cuts approx. 1½" apart
   2. 40" - 60" arch windows, space kerfing cuts approx. 2" - 2½" apart
   3. Eyebrow arch windows, space kerfing cuts approx. 3½" - 4½" apart
4. A skill saw, table saw or radial arm saw can be used to kerf wood.
5. Formula to figure the length of wood needed: Ex: 40" (FW of treatment) The size of the board is half the diameter which is 20" x pi (3.1416) = 62.83" or 62f" (length of board).
6. Use 1 x 4, 1 x 6, or 1 x 8 board for an outside mount.
7. Completely wet the board before bending. Let the water absorb into the wood for an hour or two or until the board bends easily into the arch shape. The wood will crack or break if it is not soaked.
8. Use 1½" nails, 1d" staples or screws to secure shaped plywood to kerfed board. (A brad nailer or staple gun can be used.) (see dia. 3 & 4) (See Quick Tips - Tools for the workroom)
    
   
   
9. Cover plywood face with blackout lining. Cover kerfed board with straight strips of blackout lining. (wood grain can show through regular lining) Use gimp to cover all inside edges. Cover top of kerfed board with face fabric. Add a layer of interlining under the face fabric cover to soften the edges of the mounted treatment. Welting can be added to top edge of the arch. Edges of face fabric should be turned under & pressed, then glued to top of arch.