At this point, plastic grommets are glued to the surface of the fabric at positions where inspection holes must be cut. Like
the rib stitches, they are covered with gussets and finishing tapes. Straight and bias tapes, some with pinked edges, are used
to cover the rib stitching and the inspection grommets. Poly-Brush is used to hold them in place. Tapes are used to cover
every seam in the fabric. Drain grommets are added at the lowest edge of the wing on the flying aircraft. Then the whole
wing is coated a second time with Poly-Brush. Whew!
The next step is rib lacing or “rib stitching”. The pink coated wing is marked with pencil and chalk line at spacing specified
in AC-43.13 (“Acceptable Methods”). Reinforcing tape, about ½ inch wide, was laid over the ribs to protect the fabric from the
lacing. Then holes are punched in either side of the reinforcing tape (and rib) with a rib lacing needle. Then the fun
begins. Using straight and curved rib lacing needles about a foot long, rib lacing cord is fed through the holes and around
the rib, fabric, and lacing, and tied with a modified seine knot as shown in AC-43.13. This takes some practice. Hundreds
of these knots must be tied over the whole wing surface. They ensure that the fabric keeps its shape during flight.