Snap fasteners can be used in myriad ways, from finishing a handmade garment, to replacing buttons on an existing shirt or for creating snap-tape for future use. Regardless of how you plan to use them, the most crucial factor for snap success is put them in the correct way. A properly applied snap will not fall off when used and will not ruin the fabric it is attached to. Luckily, learning how to install snaps is not difficult and can be mastered by testing a few snaps on scrap fabric.
Mark where you want to attach the snaps on both sides of your project and decide where the sockets and studs will go. A socket is the open side of a snap and is the equivalent of a buttonhole. A stud is like a button and fits into the socket.
Place an open prong ring on the underside of the fabric where the stud will go. The points of the prongs should be touching the fabric. Set a stud on upper side of the fabric, directly placed above the prong ring.
Close the snap-setting tool so one side is on top of the stud and the other is under the prong ring. Make sure the tool is closed securely around the pieces so nothing slips out of place.
Hold the snap-setting tool down on a hard surface and tap the tool with a mallet twice. The mallet will press the prong ring into the stud and secure the snap onto the fabric, so you may need more than two taps of the mallet to achieve a tight connection. Remove the tool when the stud and ring are tight against the fabric.
Place a socket on the side of the fabric that will face the stud and a prong ring on the opposite side, with the points touching the fabric. If the prong ring will be on the outside of your project use a capped prong ring for a finished appearance.
Place the snap tool around the socket and ring like you did for the stud and press them together with the mallet. Remove the tool when the socket is tight on the fabric.
Sandwich a layer of interfacing between the fabric and the non-visible side of the snaps to add extra strength.
Do not use parts from different manufacturers together because every snap is produced differently and the pieces may not make secure connections if mixed.