What you'll need to make your own:
-Long sleeved shirt
-Needle and thread
-Sewing machine/serger (I used both in this project)
Step 1: Cut Off Sleeves
I cut mine off as close to the seam as I could because I wanted them to be as long as possible, but you can really make them any length you like.
Step 2: Fit Them to Your Arm
Turn the sleeve inside out and put it on your arm. On mine, I wanted them to hang down to about my knuckles so I fit them with that in consideration.
Using the original seam as a guide, pin the sleeve so it fits snugly on your arm. (It was sort of hard to do this one-handed so you may want to have a friend help with this)
I then serged along where I pinned.
Step 3: Make a Thumb Hole and Finish the Edge
Once that's done, using your needle and thread stitch all the way around the opening of the hole. This will discourage fraying and too much stretching.
Then just finish the edge at the top of the sleeve and you're done! To do that, I just folded it under about a quarter of an inch and sewed all the way around.
I think I'm also gonna make a pair of these out of an old sweater for some added warmth :)