George Patterson wrote:
Stubby wrote:

Interesting because balloon envelopes are typically guaranteed for only
500 hrs. Sun and heat cause them to become porous and a yearly annual
inspection will eventually declare your envelope unfit.

Perhaps the heat reduces the life of the fabric?

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

Dacron and Stitts polyfiber are both polyester. Although plastic
formulations can differ in the filler and plasticizer, the main
differance would have to be the weave, fiber size, and fiber density.
I suspect ballons have a short life span because they must hold hot
air, and the fabric is unpainted.