Good, inexpensive oven thermometers can be ordered bulk here (note that these thermometers can also be immersed in water to measure its temperature):
Chaney Instrument Co. 965 Wells St PO Box 70 Lake Geneva, WI 53147
Model#: 00820 Price: $1.20/each Minimum order: 72
A giant site dealing with thermometers is here.
The STEVEN Foundation has quantities of reflective Mylar® polyester film available for solar cooker construction. The 3-mil film comes in rolls 62-inches wide. This film proved more resistant to ultraviolet (UV) damage than did a similar product from a different manufacturer. Interested parties would be responsible for shipping expenses, and would be invited to provide a modest donation in support of the foundation. Contact: Jaroslav Vanek. Tel: 607 257 7109, e-mail: firstname.lastname@example.org
ClearDome Solar Thermal sells their durable 97.4% diffused solar reflective foil in sheets and rolls, and top-rated 95% mirror surface SolaReflex AA polished anodized aluminum 2x4' sheets that have the longest outdoor life of any solar reflector, shown in the photo of their SolaReflex Octagon Parabolic cooker. They also have Blackflex heat absorber foil for solar cooking and other uses. Contact: Deris Jeannette. Tel: 619/990-7977, e-mail: email@example.com
See main article: Reflective material
Water quality measuring equipment
Water-quality testing kit: IDEXX (1 Idexx Drive Westbrook Maine, 04092 Tel: 207/856-0300) manufactures and sells Colilert, a 24-hour EPA-approved coliform and E. coli test that can be used in the field. Microbiologist Bob Metcalf of Solar Cookers International and others have used this simple, light-weight kit to test the drinking water brought from home by participants in solar cooking workshops. Bob has written a guide to using the Colilert test in the field which describes how to test effectively in developing countries without slavishly following the manufacturer's somewhat over-cautious recommendations. You'll find a comprehensive guide to solar water pasteurization here by Dr. Dale Andreatta.
See main article: Water pasteurization