Many weavers who use a pin loom like the Schacht Zoom Loom will tell you to steer clear of cotton yarns or that you will hurt yourself if you try to weave with it.
The main point in weaving with cotton yarn is to lessen your tension overall, and believe it or not, this starts BEFORE you even begin weaving!
Wind off approximately 9 yards of your fingering weight yarn into a small pile of yarn.
Even the smallest amount of tension coming from a ball of yarn will cause your first layers to be tight, so measuring out your yarn ahead of time is key.
Next, start laying your foundation layers down. Gently place the yarn between the pins according to the weaving instructions that come with your loom. This shouldn’t be too saggy, but you want to feel like you have just laid the yarn in.
Lay down all three of your base layers down in this manner.
When you start weaving, you’ll notice that there is a bit of slack in your “warp” threads, but as you weave, this will be taken up. When passing your needle through in this “locking” layer, be sure that you don’t tug it tight at the end of each row. As you did in the warping, gently put the weaving yarn into place.
If you feel any tension in your hands or wrists as you weave, this means your warp is too tight. Take breaks frequently, and stretch from time to time to prevent discomfort. When you get to the last couple of weaving rows, these should go by smoothly.