We have purchased a hot oil system designed for Sun 21. Unfortunately, we don't have this chemical. On the other hand, we do have Therminol 66. Will Therminol 66 work? Also, where can I get thermal and transport properties of Sun 21? - P.K.

Sun 21 data can be had by calling SunCo Inc. technical staff at (800) 832-4737. We've substituted Therminol 59 and 66 for Sun 21 and the only problem was a greater tendency for leaks with the Therminol products, which tend to be less viscous. Welded joints are recommended; screwed and flanged connections should be avoided. - acannizzaro@presschem.com