Why epoxy resin?
The most popular resin for constructing homebuilt aircraft is epoxy resin. There are several good reasons for this, including strength, durability, resistance to shrinking, ease of application and ease of repair. Although most of the strength of a fiberglass layup is due to the glass fibers themselves, all you have to do is pick up a limp, stretchy piece of glass cloth to understand that the resin is at least as important as the glass. The strength properties that come about when the glass cloth is treated with an epoxy resin (or “matrix”) is what makes fiberglass both usable and useful for sportplane builders. Durability means how well the stuff will hold up under normal use. This includes exposure to sometimes nasty atmospheric elements including raindrops encountered at very high speed, a clumsy person (like me) dropping a tool onto the wing skin, or flexing of the structure under taxi or flight loads. The continued use of epoxy for airplane skin over a quarter of a century provides
