University Products (an archival materials supplier at www.universityproducts.com), publishes this quick, easy paste recipe in its catalogue. It's ideal for small quantities. If necessary, strain the paste prior to use.
Place 1 tablespoon of wheat starch in a microwave-safe container, add 5 tablespoons of distilled water, stir and place the mixture in a microwave oven. The oven must be very clean. Microwave on a high setting 20 to 30 seconds, remove the paste, and stir. Repeat this process several times until the paste is stiff and translucent. Paste should cool before it is used.