Brass is an alloy made of copper and zinc. The color of brass can vary from dark to light based on the zinc content; more zinc content produces lighter brass. Brass is prized for its corrosion resistance; however it is quite soft so it is not suitable for all applications. Brass conducts electricity and is also a good conductor of heat. It is often used in pipes, weather stripping, trim, radiators, musical instruments, and firearms.
Machined Brass Fasteners (Screws, nuts, bolts, etc.) are made from alloy 360 brass, and non-machined parts like washers are made from alloy 270 brass.
Brass plated screws are best used for projects that are static, as in they won't be tampered with. Also brass plated screws are good for indoor use, since the chances of it corroding from the elements is much lower. Pure brass screws might be more expensive, but with that cost come the peace of mind that it will last a long time.
Brass hardware is great for hobby wood projects, it simply looks beautiful. Whether you're building a doll house or replica boat, brass gives a beautiful old world style to your project. Brass is a softer metal, and when working with wood, a pilot hole will be necessary. A lot of modern bathroom and kitchen renovations are moving away from the stainless steel / chrome look, in favour of softer gold colour brass hardware. Brass also has a softer shine than more common metals found in bathrooms and kitchen, and in a few years develops an attractive patina.
Brass is also antimicrobial, copper and its alloys, such as brass, have an inherent ability to kill a wide range of microbes rapidly. Brass and copper are used in places such as hospitals because of this ability, and can reduce chances of infection. Doorknobs, handrails, and door knockers have been traditionally made of brass for these reasons.
The anti-corrosive and water resistant nature of brass screws and fasteners make them more than ideal for exterior use. Rain, air, and humidity typically break down iron screws, even galvanized iron screws. Moisture inside wood will also rust common iron or steel screws; this is why brass works great with wooden outdoor structures.Brass fasteners also match wood colour much better than steel or even stainless steel hardware. Solid brass screws will not rust, which gives them a huge advantage over other similar rust resistant hardware and fasteners.