Portable spot welding machines allow amateurs to create decorative items such as signs and lettering without using the heavy and costly full-scale machines. Instead, they are easy to use at home. By combining electricity and heat, these welders melt the sheet metal by applying the appropriate pressure, heating it up, and then fusing the hot metal together.
Through constant heating and manipulating the welding rod, portable spot welding machines are able to bond highly conductive metal sheets permanently with ease. The term spot welding in this technique refers to the welding area where the heat and pressure are conveyed and the current applied. Portable spot welder, which is also called direct metal arc welding (DMADW), is a kind of electrical direct current welding machine. The welding equipment produces an arc between the work piece and the electrode using a specially designed electrode.
A welding system used in spot weld operations is composed of a welding pen, which carries a tungsten electrode, filler metal that can either be nickel or copper, and a shielding gas. When the welding pen is in contact with the metal, a magnetic field is produced which brings about a fusion of the two metals. The process uses both the energy from the direct current and the magnetic force produced by the welding pen to achieve the effect. These welding systems are highly efficient and can bond and weld very thick and heavy pieces of metal with a great deal of consistency. They are extremely useful for welding many different types of metals.
While producing a permanent weld in a variety of metals, these units have several drawbacks. Because there is so much variation in each material, the welder needs to use a different size of electrode for every type of metal sheet. Also, because they use such a high current, the conductors need to be very thin. This results in a higher price for each unit, but it also results in the inability to weld very thick metal sheets at the same time, because they do not generate enough energy to keep the electrodes from becoming too hot.
The MIG welder, also known as the Metal Inert Gas Welder, uses three primary electrodes to generate a welding arc. These electrodes are relatively larger than those used in the MIG welder. They have much higher melting points, because they have larger cells. There are three primary wires that carry current to and from the welded area. The welders typically have higher wattage bulbs, due to the increased power of the three wires connected in series.
Portable spot welder devices are available in many varieties. Some of them use an ionization method, while others use a chemical fuel combination approach. The differences between the two methods are subtle, but can be determined by observing the operating specifications of the different units. Units that use a chemical fuel system produce less exhaust gas than those that employ an ionization method. Units that use an ionization method produce much higher voltage and greater current than the chemical fuel systems. These and other differences between the various types of portable welding equipment are important to consider when purchasing welders for your construction projects.