Do nylon bolts weaken with age? This may sound like a dumb question, but my old P-40 kit has a couple of nylon bolts for mounting the wing to the fuselage. While they've never been used, they're 20 years old. Should I get a new pair?
Nylon suffers under UV light, so if they've been around a fluorescent light or in the sun, they're shot. If they've been in a warm place they've likely been affected by moisture and oxygen, too. Nylon bolts are cheap at Home depot. A lot cheaper than the P-40 wreck.
I scratch built a 60 sized trainer looking bird once that died on its first flight due to some sort of failure. There I was straight and level when the wing came off. When we recovered what was left of the fuselage, there was a nylon bolt stub on one side and the bolt on the other side was holding part of the wing. It is/was clear that head of one bolt sheard off, but why has never been closely examined. I strongly suspect that it had been stressed.
I have used nylon bolts on planes for years with no problem, but I always use new bolts on a new airframe. That being said, if it is easy to replace those bolts, they are cheap.
Nylon dries out. When many props in use were made of white nylon, they came with a warning notice to regularly boil the props in water for ten minutes to keep the moisture content up and props supple to avoid props splitting or disintegrating. regards Alan T.