Results of experiments with several types of adhesives that withstand bakeout temperatures of 300 °C in vacuum are given. The experiments included measurements of outgassing rates, mass spectra of evolved gases, and electrical and mechanical properties. Certain polyimide and silicone resins were found to have outgassing rates below10−7Torr litersec−1 cm−2at temperatures up to 155 °C. With the addition of trace amounts of uniform small glass spheres to obtain reproducible electrical characteristics, some of these materials also exhibited good insulating and bonding properties when used to join metal surfaces. Possible applications in the construction of experimental electron devices and other high-vacuum apparatus are discussed.