Use a mixture of cornstarch and water to make a homemade fabric stiffener. Combine 1/4 cup cornstarch and 1 1/2 cups cold water in a small saucepan and stir until smooth.
Cook over medium heat until the mixture thickens and becomes translucent. Remove the pan from the heat and let the mixture cool to room temperature before using. Dip fabric into cooled solution, and squeeze off excess. Use a dry cloth or paper towel to further blot off excess. Shape the fabric according to the pattern instructions and allow it to air dry until hard. This method produces a non-permanent very hard finish.