I can’t actually remember how long the nylon was sat on the sill; I suspect it must be at least three months. Also I can’t give a figure for how much UV radiation the samples have been subjected to, in order to do that I’d need to do some complex calorimetry, and walking past the guards to go home with that sort of equipment would probably have raised some eyebrows. So as a formal scientific experiment my methodology was pretty poor, however I got some material that’s been sunbathing to compare with my original, un-aged, control group.
The results are shown in the attached chart. The average strength of the nylon has dropped by over 8.5% in the course of those few months, and the range of strengths did not overlap at all between the control and the aged samples. I should also mention that, despite it being a hot, sunny summer, the window where the nylon was stored was only in direct light for half the day. As such this result perhaps showed a bigger effect than I was anticipating.
So some food for thought about how you store your tippet material, especially if you use strings of stacked spools attached to the outside of your wading jacket, flats bag or whatever.
In hindsight, at the same time I should have immersed some of the material in water for the same time period – I suspect that would have made for an interesting result also (perhaps I’ll do this one between now and Christmas).
Have a good weekend, James.