For potting applications, low viscosity adhesives are generally preferred. They allow better fill around electronic components and reduce the likelihood of air bubble entrapment. Two-part epoxies and modified epoxies are a popular choice as are polyurethane adhesives and silicones. UV-adhesives can be used as they offer a quick cure and don't require mixing; however shadow areas and limited depth cure means they often aren't suitable. There are UV adhesives available with a secondary cure method which can assist full cure in shadow areas.