Brass is a metal. As for all metals, you'll need a brand of glue that creates a chemical bond in order to glue pieces of brass together. When you need to glue brass, be sure not to choose a glue that is brittle or that expands.
Which Glue is Best?
The glue most suited for gluing brass to surfaces is 2 part Epoxy (Polyepoxide). There are many brands of glue to choose from which are readily available at hardware stores and supermarkets. Always check the instructions on the packaging before purchasing to ensure metal is included on the list of applications. While you're at it, check the glue for any safety instructions (such as whether to wear a respirator mask while applying it).
Preparing the Surface
Metals such as brass require a bit of roughing-up to encourage a better bond. If this procedure is ignored, the surface will be slippery and less likely to create a permanent bond. The surface must first be cleaned, preferably with an alcohol-based solution to remove any greasy substances. If you don’t have an alcohol-based solution, use neat detergent, which is a good alternative for cutting through grease. The surface can be roughened with sandpaper. Once the surface is rough, there is no need to clean off all the shavings. These shavings will aid in the bonding process.
Keeping It Together
Clamps are recommended, but if you don’t have clamps, placing a heavy object such as a large book over the glued brass can do the trick. Check packaging for bonding times, which are usually between 12 and 24 hours.