subject: Introduction To Blind Or Pop Rivets [print this page] Pop rivets, also known as blind rivets, are tubular-shaped and are installed with an installation tool, or setter. The assembly is inserted into a hole drilled through the materials that are going to be joined together. A special tool is used to draw the mandrel into the rivet, which expands the blind end of it and then snaps off the mandrel. These types of fasteners have non-locking mandrels and are not used for critical structural joints.
The reason they are not used for critical junctures is because the mandrels can fall out because of vibration, which would only leave a hollow rivet. A hollow one significantly lacks the load carrying capability of solid ones. However, unlike solid ones, pop rivets can be inserted and installed completely in a joint from only one side of the structure, remaining blind to the other side. This is how these fasteners got their names.
Before these fasteners became widely used, installation of solid fasteners required two people. One person would stand on one side with a hammer and the other person would be on the other side with a bucking bar. It wasnt long, however, before inventors experimented with other techniques and developed the pop fastener that is widely used today.
When access to a structure or joint is only possible from one side, installers will use these pop rivets or blind fasteners. So how do these neat little fasteners work? They are placed in pre-drilled holes and set by pulling the mandrel head into the body of the fastener. This causes the rivet body to flare against the reverse side as it expands. As the head of the mandrel reaches the face of the material on the blind side, that pulling is resisted and the mandrel is going to snap at its breaking point. The head of the mandrel remains encased at the blind side, and a tight joint is formed by the body remains of the fastener. The stem of the mandrel is then ejected.
So what are these pop rivets used for? Most of these fasteners are used with limits on aircraft, but they are never used for structural repairs. They are, however, effective for temporarily lining up holes. There are several variations of this type of fastener available, some of which include countersunk head, flat head, and modified flush head with diameters of 3/16 inch, 5/32 inch and 1/8 inch. These pop rivets are constructed of steel and stainless steel, Monel, copper and soft aluminum alloy.
