How To's:

Bay angles:

1. Formula for determining angle to cut: 180º minus measured bay angle, divide that number by two. (180º = straight wall) a. Example: 180º - 135º (measured angle in bay) = 45º ) 2 = 22½º (22½º is the angle cut)
    
   
    
2. OPTION 1: Measure angle of bay with a cardboard protractor from Kirsch.
3. OPTION 2: Place two index cards or business cards in the corner of the bay. Overlap the cards and staple them together. The outer edge represents the angle of the bay.

Mounting bay treatments on boards:

1. Cut miters on all boards & draw mounting lines on each board & both returns.
2. TIP: Use 1", 1½", 2", etc. metal rules to draw mounting lines. (The width of the rule serves as the mounting line guide.)
3. Cut flap style board covers for each board, instead of adding 3" add 7" of fabric to the width of each board.
4. Serge one edge of each board cover & press under 1½" for the two outside board edges. (see diagram)
    
   
    
5. Attach boards for bay with 3" or 4" mending plates. Attach mending plates on top of boards, use one mending plate at each miter joint. Use 4" mending plates if treatment is heavy.
6. Staple serged edge of board covers to front edge of each board. At the miter joint turn under the excess fabric and staple. The board cover folds should meet at the front edge of the boards. (see diagram)
7. Staple treatment, welting or cording to front of board & around returns at mounting line.
8. Pull over flap & staple or glue as usual. At the first miter joint, fold & press one side of the board cover at a time making as neat as possible on top & bottom then staple or glue. At the second miter joint, stop stapling or gluing 4" before miter & start 4" after miter. Fold & press board cover as if you were going to staple or glue. Leave the second miter joint unfinished, for traveling purposes. Finish stapling or gluing the rest of the board cover to the end of treatment.
9. Unscrew one side of the mending plate from the second/unfinished miter joint.
10. Turn the board up letting the valance fall toward the floor. Fold the board that is not attached on top of the center board. This should now be small enough to transport.
11. If vehicle can transport the entire bay, finish off both miter joints.
12. At job site, reattach the mending plate & staple or glue the board cover.
13. A very finished look is achieved for the underneath side of the board as well as the top.
14. OPTION: Dust Board Hinge Plates can be used for connecting angles in bay. (purchase Dust Board Hinge Plates from Rowley - see Sources)