Washing a new low stretch rope before use
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It is not necessary to wash a new low stretch rope before its first use, but doing so can make it perform more consistently over time, especially during the first uses.
Washing can be carried out by simply soaking (24 hours) and rinsing in cold water, by hand or in a washing machine.
Washing before use can be useful, particularly for ropes that will often be used while wet or dirty:
- Washing can improve rappel friction for the first uses.
Descent control can be tricky on a new, unwashed rope, especially if it gets wet during the first uses: a liquid can seep out of the rope, making it soapy. This liquid comes from lubricants used during the manufacture of nylon and polyester yarns, which seep from the rope when wet. Washing before use can remove these lubricants.
- Washing can reduce variations in rope length over time.
Nylon stretches when wet, then shrinks as it drys. Repeated wetting will gradually reduce the length of the rope (sometimes by more than 10%), which can be problematic if it was sized for a specific use. Washing the rope before cutting it to the desired length minimizes the variation in length during use, because most of the shrinkage occurs during the first wetting: with a 3- to 4-day soak, rope length can shrink by 7 to 8%.
Why washing is not essential:
All performance and certification tests for ropes, descenders and ascenders are performed on new, unwashed rope. So the specifications given in the Instructions for Use are valid, even if the ropes have not been washed.
An unwashed rope retains its characteristics of suppleness, length and elasticity for a longer time. Washing can also accelerate wear of any treatments (e.g. Dry treatment).