A brad nailer is a smaller version of a standard finish nailer and typically is used for attaching small moldings and trim to a woodworking project. Because brads are thinner than finish nails, they can often be used in instances where a typical finish nailer might split the piece of trim as the nail is being driven through. As such, the two tools are generally regarded as complementary, rather than mutually exclusive.
While there are many more applications for a finish nailer, a brad nailer is very handy for attaching thin strips and delicate trim. Keep in mind, though, that brads can be difficult to drive through some hardwoods and manufactured wood products such as plywood or MDF (medium density fiberboard).
What Is a Brad?:
Brads used in brad nailers are made from 18-gauge wire, which is considerably thinner than the common 15 and 16-gauge nails for pneumatic or battery-powered finish nailers. Brads also have a very thin head, which leaves a smaller nail hole after the nail is sunk below the surface of the stock. This means you'll need to do less hole filling with wood filler before finishing the piece, and in many cases, you may not need to fill the hole at all.
Brads typically range in length from 5/8-inch up to 1-1/2 inches long. Because of their short length and narrow diameter, they do not have the holding power of larger finish nails or wood screws.
As such, the applications in which a brad nailer can be used are limited to very small, delicate pieces of trim (you wouldn't likely have a need for doing any structural work with a brad nailer).
Brad Nailer Styles:
Most brad nailers are pneumatic (meaning that they require a hose to an air compressor to power the tool.
However, some manufacturers are beginning to see the advantages of a cordless brad nailer (which utilizes a combination of a rechargeable battery and a compressed air canister in the tool to provide the power to drive the brad into the wood).
Likewise, until recently, most brad nailers have been of the straight clip variety. This is to say that the magazine that holds the clips of nails runs square (perpendicular) to the driving cylinder. However, some manufacturers are beginning to offer angled brad nailers, which can be easier to fit into tight spaces. Be sure that whichever style you choose, you have a source for the appropriate style of brads to use in your nailer.
Brad nailers are generally considered a pretty safe tool when compared to finish or framing nailers, because the nails are so much smaller. That isn't to say, though, that they can't cause injury. When using a brad nailer, take the same safety precautions that you would when working with any other power tool, specifically, wear safety glasses, keep all loose clothing away from the work surface and wear ear plugs or other hearing protection if you are in a confined space with a loud air compressor.
The brad nailer doesn't use a lot of compressed air, so it doesn't make as much noise (compared to other nailers), plus a small compressor will often provide enough compressed air to easily power the tool.
As noted earlier, a brad nailer is commonly used when one needs to affix a small or thin board or piece of trim to an assembly. Using a finish nailer (with a heavier gauge nail) would likely split the board, but splitting can also occur if you place the brad too close to the end or edge of a board. A better approach is to affix the brad further into the board to prevent end splitting. Each type of wood has different splitting properties, but a little bit of experience with each type of wood (and the thickness of the wood) you choose will give you an idea of how closely you can work to the end grain of the stock without splitting.
Additionally, because brads are so thin, you may encounter some nails that do not sink all the way into the stock. This can be especially problematic with brads, as it is much harder to pound the brad all the way into the stock with a hammer and a nail set than a standard finish nail. You'll quickly find that brads bend very easily under the head of a hammer. Brads are also easily bent from knots in wood, which can cause a perfectly-aimed brad to blow-out the side of a trim piece.
Instead of trying to cut off or nail in the protruding or blown-out brad, it is probably wiser to remove it. When you have a brad to remove, instead of using a hammer or a crow bar to pull it out, try this handy tip to remove nails with ease. This trick works especially well with lightweight brads.