Home made felted slippers are easy to knit, especially on a addi express knitting machine. In this tutorial I will assume that you know the basics on your knitting machine. You can also knit with normal knitting needles if you prefer. The assembly of the knitted piece might seem a little complicated at first, but I'll try to simplify it with lots of photos.
Step 1: Size and Knitting Pattern
Use yarn with 100% wool that works well for felting. My yarn is quite thick (13 stiches = 10cm). You need 3 colors (best) or 2 colors (ok).
You need to knit squares, 6 in a chain and 2 in a chain, 8 in total for each slipper.
Approx size, one square is:
Man: 19 needles, 26 rows
Woman: 17 needles, 24 rows
Child: 15 needles, 22 rows
Small child: 13 needles, 18 rows
The squares are indicated on the drawing with numbers 1-8. For 3 colors (A-C) the order is: A-B-C-B-A-C-B-A. For 2 colors (A-B) the order is: A-B-A-B-A-B-B-A.
Step 2: Knitting the Slipper
Use the setting plain knitting on the addi express. Cast on the number of stiches you need. Knit the number of rows you need for a perfect square. Do a test-square first, the number of rows can vary with the yarn used. Going from one side to the other is one row. Going back to the side where you started is then two rows.
Change color when needed. Ends will be sewn in later.
I use a waste yarn at the end. Then I pick up stiches on knitting needle 6mm and bind off.
Step 3: Assembly, Part 1
Sew together inside out.The red lower square is no 1. The gray with the twist is no 4. No 6 is folded on top of no 5. Stitch together.
Step 4: Assembly, Part 2
The added pieces on the right side are no 7 and 8 (gray and red). Stich along the middle. No 7 (gray) should also connect to no 6 (black). Turn over.
Step 5: Assembly, Part 3
The red squares (no 1 and 8) will be on each side of the ancle. Fasten well to the tips of the gray squares (no 4 and 7) to make the opening of the slipper.
Step 6: The Felting Process
Hopefully you now have a pair of nice slippers. You can do the felting by hand, but I prefer the washing machine. Wash slippers at 40'C together with a towel or some jeans. Use a light program on the washing machine, if the slippers seems too large after the washing just repeat. If you use a heavy program they might be too small, which is irreversible. Shape the slippers while wet and let them dry. They will also adjust to your feet when you wear them.