Understanding Epoxy and Heat Deflection Temperature
By Bruce Niederer — GBI Technical Advisor
Above: The test apparatus holds five of the test samples shown below in a bath of heated oil while a three-point load is applied to the sample. It is used to determine heat deflection under load (HDUL) temperature and the effects of high temperatures on cured epoxy.
Among both professionals and amateurs in the world of composites, there are certain enduring misconceptions and rumors regarding the effects of elevated temperature on an epoxy bond. Armed with just enough misinformation to be dangerous, folks will make important decisions that can lead to costly or time-consuming mistakes that might have been avoided—if they had an adequate understanding of the principles that encompass epoxy structures and temperature. By defining some commonly used terms and briefly discussing issues surrounding epoxy application, we hope to dispel some of these misconceptions about epoxy and heat.