Staple wire thickness is measured by its “gauge.” This is a measurement of a wire’s diameter. The system of identifying wire by its diameter was originally developed 1857 to specify electrical wires by their current carrying capacity. Oddly, the higher the number, the thinner the wire. Wire is referred to as heavy, medium, or fine:
Heavy wire is typically 15-16 gauge, and used for the toughest jobs on heavy materials, like roofing or other construction materials. Heavy wire staples are also used for subflooring, framing, and for fixing boxes to pallets.
Medium wire measures 18-19 gauge and might be used for materials thicker than paper, but not as thick as wood or roofing used in construction. They’re good for heavy upholstery, paneling, cabinet construction, sheathing, and siding.
Fine wire measures 20-23 gauge. This is the type of wire you’ll see in a standard office stapler, but fine gauge wire also makes staples for trim, picture frames, furniture framing or assembly, and lighter upholstery. A pneumatic upholstery stapler may use 20 or 22 gauge staples, depending on the materials being fastened together.
Staple wire is also worked to create the point or teeth at the end of the staple legs, usually chisel-shaped for best penetration of materials. Divergent staples have chisel points pointing outward in opposite directions, causing them to splay outward when applied for a better hold.
Staples can be unobtrusive or obvious, depending on the result you want. This is partly because of the type of wire that makes the staple. Exposure to humidity or harsh conditions like salt sea air or seawater can affect a staple’s longevity and ability to stay in place.
Different types of metal used to make staples include:
Aluminum: this softer metal is good for staples that shouldn’t attract magnets. They are easy to remove and soft enough to cut without damaging a saw or scissors.
Galvanized steel: steel wire with a coating of zinc resists corrosion. Staples made of galvanized steel can handle humid or damp environments without corroding or rusting. As a result, they tend to last a long time.
Stainless steel: stainless steel staples have higher corrosion and rust resistance than galvanized steel, and they are more protected from heat and have more endurance for salty environments. They also look shiny and modern.
Copper-coated: most often used for closing cardboard cartons, copper-coated wire looks great and handle humid environments well.
Colored wire: standard office staples with a color coating for appearance or color-coding.
When choosing staples, you must match the type of staple to the tool you are using to the job you’re doing. To do this, you should understand that staple types are defined not just by the type of wire they’re made of, but also by their width and the length of their “legs,” the parts that penetrate the materials you are fastening together.
When selecting a staple, start with the type of work you’re doing and the tools you’ll use, as well as the materials you are fastening together. Make note of any special conditions, such as outdoor exposure to humidity or salt, considerations about the appearance of the result, and the quantity of staples you’ll need to complete the job. If you have questions about which staples match your tool or your project, contact Us for information.