spájet

Spájet is a Czech verb meaning to join two or more parts by heat so that they form a single piece. The term covers several metal-joining methods that use heat and, in some cases, a filler metal. In common usage, spájet includes pájení (soldering), brazování (brazing) and svařování (welding).

Pájení, or soldering, uses a filler metal with a melting point well below that of the base parts. The base metals do not melt; the filler metal is drawn into the joint by capillary action with the help of flux. This method is widely used in electronics, electrical connections and plumbing. Solder alloys are typically tin-based, with or without other elements, and the joints are strong enough for many applications but do not equal the strength of welded joints.

Brazování, or brazing, melts the filler metal above 450 °C while the base components remain solid. The filler metal flows into the joint by capillary action and forms a strong bond once it cools. Common brazing filler metals include copper-phosphorus and silver-based alloys. Brazing is frequently used for copper and steel assemblies, as well as for delicate or complex joints where welding would be difficult.

Svařování, or welding, involves melting one or both base metals to fuse them into a single piece. Various processes exist, such as arc welding (MMA), MIG/MAG and TIG welding, often with shielding gas or flux. Welded joints can achieve high strength and are used in structural, industrial and automotive applications.

Safety and preparation are important across all methods, due to heat, fumes and the risk of burns or damage to materials.