Epoxy adhesive EP21AC
for aeronauticsfor bonding

epoxy adhesive
epoxy adhesive
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Chemical composition
Product applications
for aeronautics, for bonding


Master Bond has developed an epoxy system that is UL tested as per Standard 746A. This specification is referred to as High Amp Arc Ignition (HAI), and the rating system is called PLC (performance level category). The numbers range from 0 to 4, with 0 being the best. When EP21AC was cured at a thickness of 3.0 mm, it withstood 150 arcs without ignition, thereby achieving a PLC of 0. It also passed the UL94HB flammability test. Electrical arcing is a luminous discharge of current that is formed when a strong current jumps a gap in a circuit or between two electrodes.* Arcing can arise through a number of occurrences, including breaks in the electrical insulation, corrosion, faulty insulation, exposed surfaces on the conductor, rupturing, among others. This causes the electrical current to lose its way and travel through the tainted insulation, jumping from one conductor to the other. The conduction is not controlled and the air surrounding the current is ionized and arcs, which may lead to combustion and fire. It is critical to either avoid the condition entirely, or if arcing does occur, to limit the damaging repercussions. EP21AC is a two component, room temperature curing epoxy formulated to optimize arc resistance. It is a flowable system with an easy to use 1:1 mix ratio by weight with a relatively long working life at ambient temperature. It cures at 75°F in 2-3 days or 2-3 hours 150-175°F. The optimum cure schedule is overnight at ambient temperature followed by 4-6 hours at 135-165°F. EP21AC has low shrinkage upon cure along with excellent dimensional stability.


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*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.