A pom-pom, or puff ball, is an ideal finishing touch for almost any knitted hat. However, it is not uncommon for the puff ball on a knitted hat to come loose and fall off. Whether you need to add one to a hat you purchased or a hat you made yourself, you can make one from yarn. Fortunately, making the puff ball that goes on top of a knitted hat requires little to no craft skill.
Sit a cup or mug on a piece of cardboard. Choose the mug you trace by size; the bigger the circle, the bigger the puff ball for your hat will be. Trace it twice with pencil so you have two perfect circles. Cut the circles you traced out of the cardboard.
Trace a smaller circle on each of your cardboard circles. Use a pill bottle or bottle cap as a guide. Cut out the center circles by creating a notch on the exterior edge of each larger circle. When you are done cutting out the center circles, you will have two identical pieces of cardboard that look like the letter C.
Place a piece of yarn 12 inches long between the two cardboard circles. This is the piece of yarn that will hold the puff ball together when it is completed.
Hold the two pieces of cardboard firmly together so the piece of yarn does not slip free. Start wrapping a strand of yarn from the skein around the two pieces while they are being held together. Do this until the entire template is wrapped in yarn from one side of the opening notch to the other.
Tie the yarn that is being held between the two pieces of cardboard. Use a loose slipknot so you can tighten it later.
Slip your scissors between the two pieces of cardboard at the notch you cut out. Go around the circle and cut the yarn at the edge.
Remove the cardboard template carefully. Tighten the existing slipknot and tie another to secure the threads of yarn.
Fluff the yarn threads with your fingertips. Use the excess thread from the tie you used to knot the puff ball to tie it to the knitted hat.