For this you will need 7 strings of plastic string (we call them Scoobie Doo's). One red, one orange, one yellow, one green, one blue, one indigo and one violet.
Take the red and orange string and clamp them at one side - I used a crocodile clip. Holding the two strings tightly together, use the heat gun to melt them until they stick together.
Now add the yellow string below the orange and melt this one on to the others. Use tweezers to squeeze the strands together so that you don't burn your fingers.
Continue this for the remaining colours of the rainbow.
Wrap the band around your finger so that you can judge what size to make it and cut off the excess plastic.
Use a small strip of glue to stick the two ends together and then use the heat gun to seal in to place.
Cut out a cloud shape in shrink plastic.
Draw a happy, or sad, cloud face on it.
Shrink down using the heat gun and then glue to the front of the ring. Voila!