We have all done it. We are happily spinning along and all of the sudden the fiber supply ends unexpectedly, or we overdraft and ugh! There goes the yarn end right onto the bobbin. Just thread it back through and resume spinning, right? To make a strong join in the yarn follow a few simple steps instead.
First, examine the yarn end. Consider how much thinner it is than the rest of the yarn that your are working on. If it is very tapered, untwist it back to an area that is the thickness that you are trying to achieve. Either discard the untwisted fiber if it has become too unmanageable, or add it back to your fiber supply. Just keep an eye out for kemps (knots) and second cuts because often they can be the reason that the yarn broke in the first place. If the thin area is prolonged, unwind it from the bobbin until you reach the area where the correct thickness begins and a few inches into that area, grasp the yarn with the thumb and forefinger of each hand and untwist it while drawing your hands away from each other until the ply opens and the fibers release.
Once the end is decided, carefully tease the fibers open again. This can usually be done by hand, but in extreme cases a quick brush over a lap board, or a pass with a flick card will open the ends up nicely. This is a very important step because it will allow the fibers to interlock at the join as well as they do throughout the rest of the yarn.
The final step is to blend the fiber supply in with the feathered end and resume spinning.
But what do you do if the ply breaks while you are plying? There is a solution to that as well. You need to untwist each end without allowing the twist to escape the yarn. To do this, open the lock with one hand while pinching the yarn farther back to hold the twist in place. This is fairly easy with the first end, but can be a bit tricky to hold the first end pinched while you open the second one. It can be done! Just hold the first end with the heel and last three fingers of your stronger hand while you open the second end. Finally overlap the two teased ends and mush them together, then release both ends and the twist will jump right into the spliced area and hold the fibers in place.