Natural starches come in many different forms. Starches make an excellent water soluble adhesive-paste for bookbinding, hinging prints and repairing works of art on paper. The strength and physical properties of starch adhesives can be modified by their blending with PVA, PVOH and Methocel A4CP adhesives. If needed, pH levels can be adjusted by the addition (3-5% by weight) of precipitated calcium carbonate. Any modifications must be done after the starch is cooked.
COOKING OF STARCHES to form a paste can be done in either a microwave in a deep bowl or on a hot plate in a double boiler. Either way you choose, you must stir the mixture as often as possible or you will end up with lumpy paste. If you use the microwave, heat in short 20-30 second bursts, stir, heat, stir and so on for 4-5 minutes. Either way you will have to experiment with the proportions of starch to water, but a good starting point with any of the starches is 1 part starch to 4-5 parts of distilled water.
Pregelatinized Wheat Starch needs no cooking to produce a very strong and smooth paste. It can easily be dissolved in room temperature water in just a minute or two.