pop rivet
A blind rivet; a rivet which can be fixed with access only to the factory head end; after passing the bucktail through the items to be secured, the rivet gun is attached to a frangible mandrel through the centre of the rivet, which upsets the bucktail to form the field head and breaks off when the correct pressure has been achieved.
pop rivet: one-sided fastener for thin sheet and tubes
A pop rivet is a tubular fastener designed to join materials when you can access only one side of the joint. It consists of a hollow aluminum or steel body with a frangible steel mandrel running through its center. The mandrel breaks deliberately when the rivet reaches full upset, which is the signature feature that gives the tool its name: the sudden snap of the mandrel breaking produces an audible pop.
The rivet installs quickly without heat or bucking. You insert the rivet body through aligned holes in two or more layers of sheet metal, composite, or thin-wall tubing, leaving the mushroom-shaped bucktail protruding on the blind side. A rivet gun grips the mandrel and pulls it upward while the gun body squeezes the bucktail laterally, upsetting it into a field head. Once the mandrel breaks at its weakened cross-section, the rivet is set and cannot back out because the bucktail is now peened flat against the blind surface.
Pop rivets come in several body materials and mandrel types. Aluminum bodies with steel mandrels suit most sheet metal work on aircraft, automotive trim, and light structures where corrosion resistance matters. Steel bodies with steel mandrels handle structural load better and tolerate higher shear. Stainless variants resist marine and chemical environments. Diameter ranges from 3.2 mm to 6.4 mm; grip range (the thickness of material the bucktail must deform through) varies by design, typically 3 mm to 12 mm for common types.
The main weakness is low shear strength compared to solid rivets or bolted joints. Mandrel pull-through can occur if the bucktail is too thin or if the rivet gun has insufficient power. Oversized holes or multiple gaps cause the bucktail to cup and fail to form a complete head. Corrosion between dissimilar metals (aluminum rivet in steel) accelerates if no isolation is used. The hollow body can trap moisture and permit internal rust growth.
Pop rivets sit between welding and threaded fasteners in the production hierarchy. They are faster than bolting, require less training than welding, and leave no access holes. For this reason they dominate in aerospace assembly, HVAC ductwork, and any application where weight, speed, and one-sided access are critical. However, riveted joints cannot be disassembled, making them unsuitable for service repairs or adjustable designs.