Mix the flour and salt together in a bowl. Cut in the shortening with a pastry blender or fork until the shortening is the size of green peas. Loosely separate the flour-fat mixture, still in the bowl, into 3 portions. Add ice water, a little at a time, to one portion, tossing the mixture with the pastry blender or fork until it is moist and holds together. Set that section aside. Repeat with the other portions. When all the portions are moistened, gather them into a ball and flatten into a round disc. Wrap with plastic wrap and chill 1/2 hour or more. Flour a board or wax paper and, using a floured or stockinged rolling pin, roll the pastry into a round about 1/8 inch thick and at least 1 1/2 to 2 inches larger than your pan. Fold in quarters. Place the pastry in a 9-inch pie pan and unfold. Trim the pastry 1 inch larger than the pie pan and tuck the overhanging pastry under itself. Then, use the thumb and finger of one hand and the index finger of the other to flute the edges. Place in the freezer or chill in the refrigerator for 30 minutes before baking. To prebake, preheat the oven to 400 degrees. Crumple a piece of wax paper, then spread it out to the edges of the pan. To make a weight, fill the paper with raw rice or dried peas. Bake for 20 minutes. Carefully remove the paper and rice or peas. (The rice or peas may be used again the next time you prebake a pie crust.) Fill the crust with a filling and bake according to filling directions. If the filling requires no cooking, bake the pie shell 10 minutes more.