Epoxy resins (ER) are usually available as two part compounds that start curing upon mixing, but single part coatings that can be cured thermally or with UV exposure, are also available. Epoxy resins exhibit good abrasive and chemical resistance, as well as reasonable humidity resistance. The coating is virtually impossible to remove and rework requires burning through with a soldering iron. A buffer is recommended around delicate components, since film shrinkage occurs during polymerization. The shrinkage can be minimized by curing at a low temperature. Epoxy resins can be applied by brush, spray, or dip-coating. Figure 3-3 shows an example of epoxy polymerization, where epichlorohydrin on the left reacts with a dialcohol to form an epoxy resin.