A metal adhesive is a natural or synthetic substance used to join or connect two or more metal surfaces together with a bond that is strong and flexible enough to resist separation when subjected to movements, stress, high temperatures and other adverse conditions.
The bond is formed by the adhesion or the bonding by chemical and physical forces between two different surfaces or particles – in this instance, between the metal and the adhesive substance.
The use of metal adhesive is the faster and easier alternative to soldering, using bolts on drilled holes, and other methods to join metals together. Environmentally friendly, solvent-free metal adhesive brands without strong odors are available. The term metal adhesive is used interchangeably with metal glue, metal cement or metal paste.
Over the years, different types of metal adhesives have been developed to join various metals intended for various uses, under varying condition for major industries as well as for small projects at home. Choosing the appropriate type of metal adhesive for the job to be accomplished is very important to get the best results. For example, will the metal to metal connection be used to support or carry a load? What are the specific conditions in the location to be joined? Is there moisture or very high temperature? Should the adhesive be quick curing or slow-curing? It is important to check the capability of the metal adhesive before making a choice.
In terms of use or function, metal adhesives are categorized as structural or machinery adhesives. Structural metal adhesive is recommended for metal to metal bonds that need to withstand high temperatures. Structural adhesives also provide long-term protection against chemicals and corrosion. They are available in varying curing speeds to suit various metal bonding requirements in the light and heavy equipment, construction, aircraft, automotive vehicle and other industries. Metal adhesives made of two-part acrylics, two-part epoxies, polyurethanes. Cyanoacrylates and silicones are considered structural adhesives. Machinery metal adhesives are usually used to improve or reinforce the holding force of threaded locks, gaskets and other joined assemblies. The adhesive seals and protects the threaded joints from moisture and other fluids that may cause corrosion by flowing into the gaps on the threads. Machinery adhesives are anaerobic adhesives, which cure only in the absence of oxygen. Many people prefer to join metals with adhesives over welding and mechanical joining methods because they are easily available, produce the desired results and do not require machinery.