Plantar fasciitis is a painful condition of the heel and foot. It is most pronounced in the morning after a night's sleep, and can make your first few steps very difficult. This is caused by the foot's natural propensity to relax during sleep. The result is contracture of the tissue in the foot's sole so that upon walking the tissue stretches and pain ensues. Maintaining the foot in a dorsiflexed, or upward, position during the night with a splint helps to minimize the tissue's contraction.
Slice the plastic sheet using the box cutter knife. Slice along the length and width so that it is 4 inches wider than the widest part of your foot or calf. It should be as long as the distance between the tip of your big toe to your mid-calf.
Set the oven to heat at 290 degrees F. If the heat-moldable plastic manufacturer suggests another temperature, use that instead. Place the plastic sheet on the oven rack and heat for 2 minutes or as suggested by the plastic sheet manufacturer.
Remove the plastic sheet using oven mitts. With your mitts still on and while the plastic is soft, bend both long edges upward, forming a 2-inch-high lip on both sides. The finished product should resemble a trough that is open at each end.
Bend the plastic sheet along its length, in the direction of the lips, and make an "L" shape. The sheet should be bent so that approximately 60 percent forms the top of the "L" shape and 40 percent forms the bottom of the "L" shape. If needed, warm the plastic to soften it again. The bend should be a gentle curve and not a sharp angle because it will rest behind your heel.
Spray the adhesive on the inside of the shell. Place the foam rubber sheet into the inside of the shell to affix it to the inner surface. Make sure it adheres to the inside edges of the side lips.
Hot-melt one end of each Velcro strap to the outer surface of the shell. Glue two straps to the top part of the "L" shape and two to the bottom of the "L" shape to hold your leg and foot in place, respectively. Make sure the Velcro is oriented so that when it wraps around your limb it can fasten on itself.
Use the glue gun and cord to permanently create struts. Start by tying the ends of the nylon binding cord together. Make sure you tie them so that the loop will go around the outer part of the shell, from the calf to the ball of the foot. Glue it in place to the foot and calf segments of the outer shell.
Put your leg and foot into the splint. Strap your limbs in place with the Velcro straps. Insure that your leg and foot are firmly strapped in.