Adhesive bonds are usually heated in gas or steam hot-air ovens, though occasionally infrared, dielectric or induction heating is used. Curing using heat requires carefully controlled temperature and cure-cycle time. The selection of cure time, rate of heat rise and cool-down rate are dependent on the adhesive formulation, the type of joint and the expected service condition of the bonded joint. From a production standpoint, the best adhesives are those requiring the simplest cure. Adhesives that cure with heat include acrylic, ceramic cement, cyanoacrylate, epoxy, film, polyimide, silicone and urethane.
Some adhesives polymerize on contact with slightly alkaline surfaces.
In general, ambient humidity, both in the air and on the bonding surface, is sufficient to initiate curing, within a few seconds, to handling strength. Optimal humidity is between 40 and 60 percent at room temperature. Higher humidity accelerates curing, but may impair the final strength of the bond. These adhesives offer flexibility, because they will bond almost all materials. After adhesive application, parts must be joined quickly, because polymerization begins within seconds.