There are a number of options to look at when trying to answer this question. Many adhesives are available that will do the job. The range of products available includes epoxies, structural adhesives (acrylated urethanes), threadlockers, and other adhesives that all offer excellent adhesion to metal.

Typically, the first choice that comes to mind when we need to mate two threaded parts is anaerobic threadlockers, which are available with different degrees of strength and torque resistance. There are permanent threadlocker grades available on the market from a number of suppliers. Epoxies offer brute strength as well. Structural adhesives such as acrylic or acrylated urethanes include the Dymax 846-GEL families or Loctite 300-series structural adhesives, which also offer exceptional strength.

The questions that need to be answered to inform your product choice include: What types of metal and plastic are being adhered together? There is a difference between bonding stainless steel or cold-rolled steel to anodized aluminum or galvanized zinc. The same is true for plastics. What type of environment will the part be exposed to? Can we use an activator to cure the material, or can we use heat or other curing methods? What is the bond gap between the surfaces? Does the material have to be medical grade? Does it require impact strength?

There are a number of options and trade-offs to consider before we can identify the best system for your application. Contacting a local representative or distributor may be the best way to determine the most suitable adhesive.