Nylon overview: Care and trade-offs

Water absorption, wear, storage and sunlight affect performance. Inspect actual condition rather than imposing one replacement calendar. A fluoro surface does not erase the nylon core's behaviour.

Stretch, cycles and retained strength: measured evidence

Working strain ε = (loaded length − original length) / original length. Residual strain εr uses length after unloading and waiting. Length recovery = (ε − εr) / ε. Retained strength requires a separate post-cycle break test — recovered length does not prove recovered strength.

Applied force is not the label rating. A 3 lb force is 30% of a 10 lb label but 21.4% of a 14 lb label; these are not equal stress. Record material, diameter, wet state, time, temperature, preconditioning and knots.

Fixed 3 lb (about 13.34 N) force, nylon specimen. TackleTour, 2007 specimens, approximately 24±1 inches: Berkley Trilene XL, PA · 12 lb · 0.32 mm — dry 9.4% loaded strain and 0% residual; after a 3 h soak 10.4% and 0%. Loading rate and exact holding/recovery times were not fully reported; these are not safe drag settings, and zero residual reflects reporting precision, not unlimited cycles, zero damage or complete strength retention.

Cycles at 30% / 60% breaking load. Thomas & Edwin (2009): 1.5 mm PA6 longline mono, initial break load 440.52 N and break elongation 47.87%. Cyclic peaks at 30%/60% of wet breaking load (about 132/264 N), 120 mm/min, 5-second endpoint pauses, 10–180 cycles, six replicates per condition. Reported break-load losses were about 3.0%/4.6%. These are strength losses, not strains at those loads; do not extrapolate to thin bass-fishing mono.

Measurements at break. Shimadzu: 200 mm initial grip spacing, 200 mm/min. Four nylons: maximum force 4.688–5.585 N, break displacement 36.451–41.466 mm, about 18.2–20.7% of initial spacing. One FC: 4.721 N, 43.285 mm, about 21.6%. Grip displacement is not local extensometer strain or working strain. Do not pool these with longline samples into a material range.

Missing is not zero. Do not linearly extrapolate one point or predict recovery from label strength. Material sets tendencies, while orientation, crystallinity, structure and processing affect the finished curve; time-dependent polymer deformation applies to nylon and PVDF.

Sources: TackleTour · 3 lb stretch (2007) — https://www.tackletour.com/reviewfluorocarbon2.html · TackleTour · residual deformation (2007) — https://www.tackletour.com/reviewfluorocarbon2pg2.html · TackleTour · tested specifications — https://www.tackletour.com/reviewfluorocarbontestpg2.html · Shimadzu · tensile test — https://www.shimadzu.com.au/industries/engineering-materials/textile/various-fishing/index.html · Thomas & Edwin · cyclic PA loading (2009) — https://epubs.icar.org.in/index.php/FT/article/download/16362/7879/35583

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