I still recommend using Filzwolle to do felted slippers, as it is a thick yarn (important for slippers so they won't wear out too quickly) and if you follow my pattern, you will end up with a pair of slippers that will fit the shoe size you want to achieve.
However, what if you want to make something else? Do you have to stick with specially created felting yarn or are there other options?
Well, the short answer is that many woollen yarns will felt as long as they have no or only a minimal acrylic content and they have not been given the super wash treatment. Also, the less a yarn has been plied, the better it will felt. (I am not referring to the weight of the yarn here, but to the way the yarn has been 'twisted'). If a woollen yarn is strictly "hand wash only", then you stand a pretty good chance that it will felt when put through the washing machine!
They are slightly challenging to work with due to the fact that they are not plied, but that is more than made up for by the fact that the stitches come out very evenly. And best of all, they are ecological yarns, made under very strict environmental conditions and with no chemicals used in the production process.
I decided to give felting with Eco-Ull a go and designed a small handbag in two colours. The basic pattern is simple and can be done by a beginner knitter - knit a flat rectangle in two colours, with garter stitch marking the edges, and stocking stitch for the main body part. I worked the shoulder strap as an i-cord over 6 stitches and assembled the bag before putting it through the washing machine for felting.
Felting works best when the item swims in water during the process.
However, I didn't want to run the machine just for a small bag, so I decided to take the risk and throw it into my front loader with other coloured washing and ran the machine at 40 degrees standard cycle.
I did make sure not to overload the machine so there would be enough water sloshing around the bag to help with the felting process.
The bag came out beautifully. It shrank a fair bit (from 19cm height to about 12cm for the final product) and it is possible it wouldn't have felted and shrunk quite as much if I had only washed the bag and nothing else, but the felting worked really well, and the felted fabric is just gorgeous. The colours were not affected at all - a success all around!
If you would like to make this bag, I have added the pattern for the "Felted Bag" to my accessories pattern collection. I used two balls of Marks and Katten Eco-Ull (Aran weight) in Colour 306 (Moss Green) and one ball of Eco-Ull (Aran weight) in Colour 313 (New Red).
If you think you would like to try your hand on a more ambitious felting project, you could also have a go at making the felted basket in Filzwolle. I am sure this would also come out well when using Eco-Ull, but the size would probably be different to the original.