A portable spot welding machine, sometimes known as portable welding machine or portable heat welding machine, is used to securely weld two or more pieces of metal together. These welding techniques include but are not limited to cold welding, brazing, friction welding and gas tungsten arc welding. The primary benefit of these types of welding techniques is that they can be performed in a safe and controlled environment, indoors or outdoors, by skilled workers. Some of the most popular portable machines are the portable gas welding machine and the portable electric welding machine.
Gas and Electric portable spot welding machines are both power based. In either case, the weld process is almost identical to that of an arc welding process. Many times, these types of welding machines are also referred to as wire feed welders. Both types of machines work on the same basic principles of creating a highly conductive metal fabrication material.
Gas portable spot welders work by injecting an appropriate amount of gas (the gaseous fuel) into the base materials that need to be joined. This gaseous fuel mixture provides a very strong current which heats up the base materials to an appropriate temperature where bonding can take place. Many times, the gaseous fuel is ignited with a hand torch, as the current produced by the welding procedure is extremely hot and effective.
The electric portable spot welding machine is often used to join thin metal sheets, such as cans or bottles. When an arc is created, the electrical current heats the sheet and forces the bond to adhere much more tightly. While using an electric machine to create this type of weld, the welder is able to control the heat settings of the welding process. The most common uses of this technology is to join thin sheets of metal using short, continuous welds which create the best welds possible. An arc is created when compressed air or propane fuel (LP or LP-gas) is introduced into the welding chamber.
The thermal conductivity of metals is increased during the welding process, allowing more current to be generated within the rod. This increased current is transferred through the welding rod tip to the welding materials being joined. When a material is welded, the thermal conductivity increases significantly. This increased resistance to heat allows the metal to be molten at a much faster rate, therefore allowing more materials to be joined at one time. The increased friction and cooling effect of the metal allows it to be pressed into the desired shape without any of the internal stress that occurs during the traditional metal joinery processes. Many times, the portable resistive spot welding machines are used to create joints in alloys, stainless steels, and cold rolled steel.
A high tolerance metal joining method that utilizes two different electrode types is called alternating current metal arc welding (ACAW). In this type of procedure, a lower current is allowed to continuously run between two conductors while a constant current supply runs between the two other end of the two conductors. When the two different metals are joined, the current is supplied only to the conductors that are being joined, creating a very strong weld. This is one of the most commonly used methods for welding several pieces of steel together.