In my previous Technical Tuesday posts, I covered blocking and cautioned about agitating the knitting too much because it will cause felting. I had a couple people email with questions about felting, so I thought I would dedicate an entire post about it. If you understand how things become felted it will be easier to avoid felting or do it on purpose.
The picture above may look like microscopic photos those shampoo commercials use to demonstrate split ends, but they are actually different yarn fibers. You will notice the four on the left look a little spikier and jagged than their counterparts on the right. Felting is caused when you rub two of those fibers together and the split ends get hopelessly tangled together. The rough edges want to stick to one another and never let go.
If you look at the polyester, on the far right, it looks like a perfectly straight tube. It has no rough edges or spines sticking out from it so it would be almost impossible to felt this fiber. This is why you can throw most synthetic yarns (acrylic, nylon, polyester) into the washer and drier.
Superwash yarn would look similar under a microscope. Superwash yarn is created when a fiber is soaked in an acid bath and all those little spines are burned off. This creates the ideal yarn for socks and baby knits, since it retains the natural fiber content, but is easily washed. An interesting fact, some people have a sensitivity to superwash yarn, but it can be a response to the lingering traces of the acid bath on the yarn.
In order to understand felting on purpose, here is an instructional video on felting oven mitts!
I really like the oven mitts and this is an excellent idea for housewarming gifts, you could felt matching pot holders too. I have the sudden urge to felt a coffee cup cozy… I may have to check into my non-superwash stash and see what I can felt up!