Until the mid-20th century Ukuleles were strung exclusively in gut, a material that had been used for thousand of years and that combines excellent promptness of attack with brilliance of timbre - very different, in other words, from modern nylon strings. And until recently the typical sound quality of gut has been a constant point of reference for luthiers, composers and performers alike.
A fundamental aim of Aquila's research has therefore been to make a new synthetic product having the same acoustic properties as gut - but without its typical defects (high cost, limited duration and high instability under varying climatic). Nylgut® has precisely these qualities: allowing one, on the one hand, to rediscover the sonorities familiar to the great 19th and 20th century Uke masters; and guaranteeing, on the other, a stability of tuning higher even than that of the best gut and nylon strings.
Just like gut, Nylgut® is liable to suffer from cutting edges. Before stringing the instrument do make sure the nut and bridge are free from sharp edges and the nut grooves not too deep and perfectly smooth. You can get rid of sharp edges with very fine grit sandpaper (600, for example) or the finest steelwool (000).
The best sound quality develops when the strings have completely set, which may ordinarily take sometime. To achieve a stable intonation in just a few minutes you can repeatedly pinch each string at midlength with your fingers, pull it decidedly sideways and tune it up again. Stop when the string does not pull out of tune anymore.