That said, they are a pain to make especially when it comes to PVC bows. Back when I used to carve, scrape, chisel, rasp, file, grind, and sand wood into bows I would spend hours of work. After the long and tedious process of teaching wood to bend, half an hour making a string doesn't sound so bad. Yet when I can whip out a shootable PVC bow in half an hour, spending the same amount of time on a string turns on my procrastination mode. As a result, most of my bows only have strings when they need to have strings.
Yet at this last gun show, I met a viewer of mine and he gave me a present. It was a 3-bundle counter-twist (Flemish) string with only one loop. Seeing that string snapped me back to my early days of building bows, before I got good at the two loop Flemish string.
Back then I used to make very long one loop strings for all the steps in the tillering process. I could adjust the length with a timber hitch and go from long-string tillering, half-brace, brace, and initial shooting all with one string. Cut the loose end off and you have a permanent string that is tied to one nock of your bow.
For some reason when I started building bows out of PVC pipe, I completely forgot this old method. I used only the two loop Flemish and continuous loop (endless loop) strings, probably because they were "real" bowstrings. While those strings are great, there is nothing wrong with the one-loop string. It makes a great primary string that can be made quickly and made in advance because the length is adjustable. It also makes for a great backup string to keep in a pocket, bag, car, quiver or bow case. The best part is that it can be made from the same low-stretch, high-performance materials as the other types of string.
Hopefully this method of string-building makes things a little easier and quicker for you. Try it out and let me know what you think!
P.S. - If your bow has siyahs or you need larger loops, check out Tim Piatek's tutorial on tying a Turkish string loop here. I first saw that style of loop on bows from Mongolia, but it's a popular style of tying string loops. It allows a very tough loop of rawhide or thick rope to be used to protect the bow's nocks while still retaining the performance of a thin string.