aerorigging 6 #1 Posted August 1, 2021 Hi Im looking for more info of "shelf life" parameters / storage conditions of parachute fabrics/webbings/lines other than the 3,5 years (MIL-DTL-6645J ), Im trying to learn & understand where that 3,5 years come from. I found very little information on degradation over time for raw materials on the shelf. On the military side, the government allows for shelf life of raw materials of 3 years or 5 years depending on the contract. On the civilian side there is no reference to shelf life on the regulations. The degradation of Nylon or other synthetic fibers is insignificant when sitting in a humidity and temperature controlled environment. Real damage UV lights (artificial fluorescent lamps or other), I already read the Wilcox study. I know every manufacturer specifies their own "service life" depending on their experience and preference. Any info would be appreciated Nico Quote Share this post Link to post Share on other sites
riggerrob 558 #2 August 20, 2021 Performance Designs discards nylon thread that has been sitting on the shelf for more than a year or three (I forget the exact number). They say that nylon thread gets stiff and brittle if it sits on the shelf too long. Quote Share this post Link to post Share on other sites
JerryBaumchen 1,046 #3 August 20, 2021 3 hours ago, riggerrob said: Performance Designs discards nylon thread that has been sitting on the shelf for more than a year or three (I forget the exact number). They say that nylon thread gets stiff and brittle if it sits on the shelf too long. Hi Rob, Re: nylon thread gets stiff and brittle if it sits on the shelf too long. Have you ever experienced this? I know I have not. How about some of you other riggers? You are the ones who would have thread, webbing, etc, that is quite old. Jerry Baumchen PS) I know that this is a dilemma but I really do not know what is a 'too long' shelf life. Quote Share this post Link to post Share on other sites
fcajump 153 #4 August 31, 2021 On 8/20/2021 at 1:52 PM, JerryBaumchen said: Hi Rob, Re: nylon thread gets stiff and brittle if it sits on the shelf too long. Have you ever experienced this? I know I have not. How about some of you other riggers? You are the ones who would have thread, webbing, etc, that is quite old. Jerry Baumchen PS) I know that this is a dilemma but I really do not know what is a 'too long' shelf life. Anecdotal story told to me by a DPRE when working on my Masters rating was of a Master Rigger that had just done the major repair of replacing main lift webs/risers on a rig with the proper thread (cordage) only to have a catastrophic harness failure. Cause was traced down to his thread being stored where it was exposed to daily sun through a window. Testing of his thread found it was brittle/degraded with the conclusion being the degradation being due to UV. But when properly stored, does it breakdown in the absence of UV/chemical/heat sources... not that I know of... (and yes, for many reasons I am one that refers rigs over 20-25 years to other riggers) JW Quote Share this post Link to post Share on other sites
