A pop rivet is a single piece of metal with a long pin, or mandrel, at one end and the rivet at the other.
The Rivet Tools
To use a pop rivet, it is necessary to first drill a hole the diameter of the rivet in both pieces of material you intend to rivet. Pop rivets are usually used to join thin pieces of metal or plastic and are useful when the hole can only be accessed from one side. To set the rivet, you will need a pop rivet tool, often called a rivet gun or pliers.
Setting the Rivet
To set a pop rivet, align the holes in the two pieces of material to be joined, then insert the long pin of the rivet into the rivet tool and the rivet end through the holes. By squeezing the handles of the rivet tool together, the pin is driven into the rivet. Simultaneously the body of the rivet expands and flares on the underside of the join so that the rivet can't pull straight up through the hole. Pressure on the pin where it meets the rivet head eventually breaks the pin, leaving a neat join with no protruding ends of metal.