I often get asked which wool fibres are better for feltmaking and the truth is most wool will felt to a degree, depending on your choice of technique and your method. Generally for ease of feltmaking you are looking for fibres with a micron count (thickness) close to Merino 64's (21 micron)... so a low micron number is usually good. These fine fibres tend to lock and tangle more easily than the thicker ones.

Thicker fibres can also be felted, but will take a lot more rolling and work in the fulling process. Some fibres also prefer a bit more olive soap to aid their tangling, especially if they have a mix of fine and coarse guard hairs (Welsh Mountain Wool, or Suffolk).

There are however contradictions to this general rule and I believe that the reasoning in their exception is to do with the shine (lustre) of the fibre. A high shine fibre generally has fewer scales across the length of the individual hair, thus creating light reflection and shine and I have found that these fibres are much harder to make felt with. Alpaca is a high shine fibre with a low micron count and is a nightmare to felt on its own... but can be done. This is why high lustre fibres are generally used as blends.

Let’s look at a Matt fibre; Shetland has a higher micron count, thicker than Merino but felts up well and I believe that this is because it is a much more matt looking fibre (more scales).

All in all I'd say for easy feltmaking (especially for feltmakers) avoid shiny fibres and stick to matt fibres with a smaller micron count... these have more scales and are fine enough to create an easier felt effect.

I hope this helps?
Sara.
eBay shop: Sara's Texture Crafts