Joining

separated on the loom

New end from shuttle and end on the loom

fluff on fluff

joined, by the twist migrating from the new end into the fluff

Connected end ready to weave

Some notes: It is important to pinch the new end close to the end to keep the yarn from untwisting.If you have allowed it to untwist and the ends will not join, pinch the new yarn about 3" from the end, twist the end by hand, then put fluff on fluff and release the pinch. The twist in the new yarn should run immediately into the fluff.