Things You'll Need
Hot glue sticks
Cardboard tubes have many household uses. You can use them to store scarves in a drawer, safely store sharp kitchen knives, make a plastic grocery sack dispenser, and keep documents from tearing or wrinkling during transport. You can also use cardboard tubes for a number of craft and educational projects. For instance, cardboard tubes are great for making musical instruments. Make sure that children have adult supervision when making cardboard tubes, as glue guns can get very hot and cause burns.
Roll the long edges of the cardboard rectangle toward each other until their ends meet. Overlap the edges slightly.
Heat up the glue gun with a glue stick in the barrel. Once hot, lay down a line of glue along the entire length of one edge of the cardboard.
Press the overlapped edges together firmly and hold until the glue dries. After one minute, loosen your grip slightly. If the edges give way, continue to press the edges together until the hold is firm.
Make sure glue is completely dry before using the tube for anything. Reinforce the seam with more glue if necessary.
Always unplug the glue gun when you are done with it, and clean up any leftover glue before it hardens.