Gather your supplies.
Tape cardstock of your choice around a paper towel roll.
Add another decorative strip of cardstock to one end to cover the rest of the paper towel roll.
Nail four holes into the top of a bottle cap.
String two long pieces of thread through the four holes so that they cross in the middle, and leave a long strand coming out of each hole.
Hot glue each end of the spring and attach to each bottle cap with the threaded cap facing outward and the plain cap facing inward.
Hole punch the end of the paper towel roll on both sides.
Pull two threads through one hole and two through the other.
Hot glue the outer bottle cap to the end of the roll and tie all four threads in a knot.
Fill the open end of the roll with confetti.
Pull back on the string and let go for an explosion!!