Last fall I made a tee shirt rug for a Christmas gift. Now I can show the pictures! I cut the strips 1 1/2” and got approx 32 yards from one tee shirt, size large. I cut across at the arms and included the sleeves. I followed this tutorial to make my 'tarn' - tee shirt yarn, though I used my rotary cutter and ruler to cut the strips. It was stretchy and soft, worked up fast and was MUCH nicer to knit than my cotton rag rug.
Garter stitch - knit every row
Needle size: 15
Strip width: 1 1/2”
44 stitches equals approx 24 inches, the width of the rug
18 stitches to a yard of tarn
Many of the tee shirts were in our rag bag, some I bought for 25 cents at a rummage sale. I found the well used tee shirts were softer and knit up nicer.
I made the tarn one tee shirt at a time, joining the new color as the old one ran out, and I didn't roll it into a ball because it was a lot easier to work with laying loose. As I knit I would occasionally untwist the tarn yet to be knitted. That helped it lay better when it was knitted.
Each strip of color is approximately one large tee shirt. I decided to keep the width of the colors about the same so when I made tarn from an extra large I ended the color and used it again later. Wow, we had a lot of greens and purples in our rag bag!
It was a little tiring on my hands, so I knit two row a day from mid October to mid December. Yay, finished with time to spare! It's thick and stable and fun. If I was going to do it again I would probably cut the strips 1". I have no idea how washable this is.