A good way to glue metal to metal is using two-part epoxy. Other options include structural adhesives, which are especially good for components that support a load, and mechanical adhesives, which augment seals.
It is important to make sure the metal surfaces are clean. Also, many adhesives have specific directions for surface preparation, so it is wise to read the instructions for exact details.
The cure times for adhesives vary from one to another, so ensure that the amount of time a given product allows between application and setting is sufficient to properly position the items.
Typically, two-part epoxies must be mixed in equal amounts. This may require some type of disposable surface, such as a spare block of wood, that can be discarded when no longer needed.
Considerations when purchasing structural adhesives include thermal expansion, resilience and resistance to moisture. On the other hand, machinery adhesives are best for preventing lateral movement and protecting against corrosion.
A number of adhesives stick to the skin in addition to metal surfaces. It is therefore advisable to wear latex gloves when working with these substances.