Almost any glue for metal that can be found in stores has high strength. Most often, the bonded structure is destroyed not inside the adhesive layer, but at the borders of the metal being joined. Thus, the strength of the adhesive bond primarily depends on the surface preparation.
Typically, the coating is contaminated with various oils, scale, paint residues, traces of corrosion. All this can be eliminated both chemically and mechanically.
Before applying the adhesive to the metal, the contaminated surface is treated with solutions of acids or alkalis, as well as with special compounds for removing rust and cleaning. The action of acid or alkali is based on the fact that oxides are destroyed faster than the base material. Cleaning with chemicals is faster and cheaper than machining. In addition, a resistant layer forms on the metal surface, increasing the strength and durability of the adhesive joint.
Mechanical surface cleaning is also performed before applying metal adhesive.
In this case, they are processed using abrasive materials (metal brushes, shot blasting
machines, sandblasting or sandpaper). The resulting surface becomes more rough, which increases the area of interaction of the adhesive and metal, therefore, increases the strength of the connection.
Today, various adhesives for metal are presented on the market, which have their own characteristics and composition.
One common material is polyvinyl acetate glue (PVA). It allows you to work with wood, glass, metal, leather, fabrics, etc. The substance is applied in a thin layer on pre-fat-free surfaces that are tightly compressed. Glue setting takes place after 20 minutes, complete drying is observed after 24 hours.
Such a well-known adhesive for rubber and metal as "Moment" is also in demand. It is also capable of joining wood, ceramics, plastic, felt, rigid polyvinyl chloride, etc. This material is toxic and flammable. It should only be used with it in well-ventilated or open rooms, away from sources of fire.
The agent is applied in a thin layer to prepared surfaces, held for a quarter of an hour, and then compress the materials to be joined for several seconds.
Almost everyone knows about epoxy glue, which also allows you to connect metal, glass, wood and other materials. In addition, the tool is used to seal cracks and holes, it can be used as a varnish coating.
This metal glue has oil and water resistance, and also serves as a good insulator. The substance is toxic. If it comes into contact with the skin, wash it off immediately with warm water and soap. The product cannot be used for gluing food products. The glue itself is prepared using the supplied resins and hardener in a ratio of 10 to 1. After mixing for 10 minutes, a thin layer of the solution should be applied to the surface, and then combined. Partial polymerization of the solution will occur after 4 hours, complete solidification occurs within a day.