Tools and Equipment - Felting Needles
A felting needle has no eye like a regular needle. Instead it has tiny notches along the shaft. As you 'poke' fibre with the needle, the fibre catches in the notch and gets pushed through the backing felt surface. The more notches (sometimes called barbs) on a needle, the more fibres get caught and the faster the fibre will felt. As well as being pushed through the felt surface the fibres will also start to cling to each other with the tiny scales along their length. The more 'scaly' a fibre the faster it will felt. This is why silk doesn't felt on its own - it's too smooth. If I'm using silk on its own it is usually as an embellishment pushed into the base material, rather than truly 'felted'.
Felting needles come in many sizes (or gauges) and shapes. They are usually colour coded so you can tell what you're using. Colour coding varies between suppliers. I use Heidi Feathers needle and refer to their colours. Gauges range from 32G to 42G (finest)
The GAUGE refers to the diameter of the needle. A higher gauge means a finer needle with smaller and sometimes fewer notches.
The SHAPE refers to the cross section shape of the needle. The most common is Triangular/Regular which has 3 sides. Other shapes are Star (4 sides), Twisted/Spiral, Reverse (inverted barbs), and Crown (notches near tip on three sides).
Personally I tend to use just 3 coloured needles. Red (38 regular) is my main 'go to' needle. Silver (32 regular) is for edges and horizons as it makes a deep line. Gold (42 regular) is for fine details, finishing and delicate fibres like silk, angora, flax.
Needles can be placed in multi needle holders which makes for faster work. I use a 3-needle pen style holder most often but have large 10 and 20 needle holders for starting large backgrounds (they still get finished with smaller needles for a smoother surface).
So that's the basics of felting needles as I use them. Hope it gives you an insight into the process of makes a fibre picture!