Good question! I didn’t know any difference either until a member in my club that is retired from owning his own body repair shop and has built close to 200 planes explained it to me. To vastly paraphrase his words; cowls and wheel pants made with epoxy resin have a flawless finish that is ready for prime and paint out of the box. Many modelers like that feature, however they are brittle and crack easy from vibration or mounting hardware installed to tight. Polyester resin parts on the other hand requires more work to finish but is much more durable.

He had a favorite supplier for “Poly” cowls and pants but they have since changed hands and moved. He couldn’t remember the name of the Co.


* spuck5644 & WORNBOOTS Thanks for the info