Welding, Soldering & Bonding Lecture Review

A collection of vocabulary flashcards covering soldering methods, welding types, gases, brazing, and bonding techniques relevant to aircraft maintenance.

Soldering

A process of joining metal surfaces together with a metal alloy (solder) that is designed to melt at a temperature lower than the melting point of the metal it joins.

Solder

An alloy of two or more metals that functions as a filler metal while forming a physical and electrical bond through the application of heat.

Soft Solder

An alloy consisting of tin and lead (often with silver or other additives) that melts at temperatures below $370\,^{\circ}\text{C}$.

Hard Solder

A silver alloy, often called brazing alloy, used when greater mechanical strength or exposure to higher temperatures is required.

Flux

A cleaning agent with a melting point lower than solder that removes oxidation during soldering and allows the solder to 'wet' the metal.

Wetting Action

The free-flow and spreading of solder to form a uniform, smooth, unbroken, and adherent film on a base metal, forming a metallurgical bond.

Dihedral Angle

The tangent angle at which solder meets the surface of the metals being soldered, used to measure wetting action.

Isopropyl Alcohol (IPA)

A general-purpose solvent used in the soldering environment for the removal of salts, residues, flux, and finger oils.

Resistance Soldering

A process used in large volume production involving a low voltage transformer that heats the metal to be soldered when the circuit is completed through electrodes.

Torch Soldering

Also known as 'hard soldering,' this method uses a flame (often butane) to heat solder and is preferred for brazing and silver soldering large work.

Dip Soldering

A process generally used on printed circuits where connections are immersed into molten solder after being dipped in liquid flux.

Tinning

The process of applying a thin coating of solder to the working surface of a metal to assist heat transfer and protect against corrosion.

De-soldering

The removal of solder and components from a circuit for troubleshooting, repair, or to salvage components.

Solder Braid (Wick)

A common method of removing solder from PCBs where melted solder is drawn up by capillary action into a copper braid.

Cold Solder Joint

A poorly soldered joint with poor electrical integrity and lack of mechanical solidity, often appearing dull grey, chalky, or granular.

Welding

A process that joins metal by melting or hammering workpieces until they are united together.

Gas (Oxy-acetylene) Welding

A process heating metal edges to a molten state with a high-temperature flame of approximately $3480\,^{\circ}\text{C}$ produced by burning acetylene and oxygen.

Manual Metal Arc Welding (MMAW)

Commonly referred to as 'stick' welding, it uses a metal-wire rod coated with flux that melts to form a sustained electric spark called an arc.

Gas Metal Arc Welding (GMAW)

Also called Metal Inert Gas (MIG) welding, it uses an uncoated wire electrode fed through a torch with an inert gas like argon or helium.

Gas Tungsten Arc Welding (GTAW)

Also known as Tungsten Inert Gas (TIG) welding, it uses a non-consumable tungsten rod to form an arc and a manually fed filler rod.

Plasma Arc Welding (PAW)

A method using a non-consumable tungsten electrode within a fine-bore copper nozzle to deliver a high concentration of heat to a small area.

Electric Resistance Welding

A manufacturing process, such as spot or seam welding, that uses the electrical resistance of the material to generate heat for melting.

Acetylene

A chemically unstable fuel gas stored in cylinders packed with porous material and saturated with acetone to remain stable.

Neutral Flame

A balanced mixture of oxygen and acetylene burning at approximately $3300\,^{\circ}\text{C}$ that does not alter the composition of the base metal.

Carburising Flame

A flame produced by burning more acetylene than oxygen ($2900\,^{\circ}\text{C}$), used for hi-carbon steels and non-ferrous alloys.

Oxidising Flame

A flame produced by an excess of oxygen ($3450\,^{\circ}\text{C}$), used for bronze welding of steel and fusion welding of brass.

Flashback

A condition caused by an overheated tip where gas ignites internally before passing out of the tip, identified by a shrill hissing or squealing noise.

Brazing

The joining of metal pieces using a non-ferrous filler metal or alloy with a melting point higher than $427\,^{\circ}\text{C}$ ($800\,^{\circ}\text{F}$) but lower than the base metals.

Bonding

The use of an adhesive or sealant to chemically or mechanically join two pieces of material.

Adhesion

The property of different molecules or surfaces to cling to each other.

Cohesion

The property of molecules of the same substance to stick to each other due to mutual attraction.

Pot-life

The period of time during which a mixed adhesive remains usable before hardening.

Capillary Action

The process of a liquid moving or flowing in a narrow space without the help of, or opposing, external forces like gravity.