A client asked this week about the relevancy of expiration dates on leaders and tippet spools. We asked John Harder at RIO for his thoughts on this subject. John is the Director of R&D, but his co-workers call him the Mono-Man. He knows his stuff and has given us some valuable information. Thank you John.
How long does a packaged last?
Personally I believe putting expiration date on leaders, especially Fluorocarbon leaders, is a waste of time.
Fluorocarbon Leaders and Tippet
Fluorocarbon leaders and tippet are a Fluoropolymer which is a very inert material and has excellent physical properties. Fluoropolymers are not affected by heat (less than 800°F), UV Light, water absorption or common chemicals it may be exposed to while fishing such as DEET or Sunscreen.
Nylon Leaders and Tippet
Nylon leaders and tippet are a completely different story when it comes degradation as compared to Fluorocarbon leaders and tippet. Modern leaders and tippets are typically made with a Nylon 6.6 Copolymer. Nylon 6.6 is a very strong Nylon Copolymer with good physical properties that meet the criteria required for high quality and high performance leaders and tippet. The downside of Nylon Copolymers is they are affected by heat, UV Light and water absorption. Like Fluorocarbon leaders and tippet, Nylon 6.6 is not affected by common chemicals it may be exposed to while fishing like DEET and Sunscreens.
Exposure to heat – Exposure to heat begins to decrease the tensile strength Nylon 6.6 at about 125°F. As the temperature increases above 125°F, the Nylon 6.6 will continue to weaken and at a faster rate as the temperature increases. The issue is exposure to temperatures above 125°F for more than a couple hours. On a hot summer day, the trunk of a car can easily exceed 150°F. Heat stabilizers in the Nylon 6.6 formulation reduce the effects of heat but do not eliminate the effects of heat on Nylon leaders and tippet.
Exposure to UV light – Exposure UV light has a similar effect on Nylon 6.6 as heat but it a slower process. Long term exposure to UV light will decrease the tensile strength of the Nylon 6.6. UV Inhibitors in the Nylon 6.6 formulation reduce the effects of UV light but do not eliminate the effects of heat on Nylon leaders and tippet.
In summary, Nylon leaders and tippet should not be exposed to heat over 125°F or exposed to UV Light for an extended period of time. Keeping you leaders and tippet in a vest or chest pack is good protection from exposure to UV Light. I doubt if Nylon leaders or tippet will be exposed to temperatures exceeding 125°F for any length of time during normal fishing conditions unless the angler throws his/her vest or chest pack in the car trunk at the end of the day. Storing leaders in poly bags has little or no effect on protecting the leaders from heat of UV Light exposure. A good policy is to replace 3X and smaller leaders every 2 years and leaders larger than 3X every 3 years assuming the leaders have not been exposed to temperatures over 125°F or UV light for an extended period of time.