Felting is a method of taking wool and shrinking it to make a dense fabric that you can use for crafts, super-warm clothing or items such as purses and wallets. Most natural animal fibres will make felt, although wool felt is the most common. You can't felt synthetic fibres or any wool that has been treated to be washable. Always check the label on wool fabric or yarn if you plan to felt it, because you must use only 100 per cent natural fibres.
Select a fabric or item. If you plan to make a sewn garment, felt the wool before cutting. If you want to make a felted item that has been knitted or crocheted, make the item on very large needles -- size 11 or 13 -- and make it at least twice the size you want it to be.
Felt the item. Put your fabric or item in a large mesh lingerie bag. Fill the washing machine with the hottest water possible and a small amount of washing powder. Set the washing machine for a hot wash/cold rinse cycle.
Submerge the lingerie bag in the hot water and start the machine. Let it agitate for about 15 minutes and then check to see if it is felting. By this time you should be able to get a feel for how quickly it is felting. Different yarns felt differently, so you will need to check from time to time. You may need to restart the agitation cycle a time or two to continue felting.
Spin the water out. When the fabric or item is sufficiently felted, or is not shrinking any more, run it through the spin cycle to remove as much water as possible. Remove it from the washing machine immediately so creases don't set.
Check the item. If you are felting fabric, you may want to felt it further by putting it in a hot dryer. If you are felting a knitted or crocheted item, you will need to run it through the washing machine again if it is not felted enough.
Dry your felt. Felted fabrics can be dried in a hot tumble dryer if they need more felting. Otherwise, pin the selvedges together, smooth the folded fabric and lay it on a flat surface such as a bed, counter or blocking board. Felted objects like bags, hats or any other three-dimensional items need to be blocked and shaped. One easy way to do this is to fill the bag or hat with plastic bags, shaping it as you go.
Felting requires three items -- hot water, agitation and detergent. Many newer homes have hot water settings with temperatures too low to felt wool. Check that your water heater is set at 60 degrees C (140F) or higher. If you don't want to reset your hot water temperature, put boiling water in your washing machine before felting your project.
Don't waste precious wool by over-felting. If you are new to this, start with a small sample or swatch to find out how your fabric will felt.