A spot welding machine is often referred to as a thermal spot welder, a resistive iron welder. The welding machine is used in a metal working environment to weld two flat sheet metals together by heating the surface to create a welder hole. When the welder reaches the end of the joint that is being welded, he or she needs to remove the piece of metal that is being welded with the help of a pneumatic table. Welded metal pieces are held in place by a continuous welded feed mechanism. This type of welding is usually done at room temperatures, which makes it appropriate for use in a wide variety of applications.
The spot welding machine produces high quality welds and is especially useful in cutting down the welding costs for many industrial and household products. It is used to join together different sized, thin but heavy grade steel sections. Typically, this welding method uses three to four electrodes; these electrodes are shaped like an arc, with the junction point located in a conical region. The thickness of the electrode wire is dependent on the wire gauge, while the rest of the welding process – the joining of the metal – occurs because the welding electrodes induce a flow of heat into the conductors.
A spot welding machine can be operated with one or more electrodes; however, if you need to join thinner metals, it is recommended to use four electrodes. When you are welding thin metals using the spot welding machine, you will need to use a vice grip in order to grip the metal correctly. Welders usually hold the metal in their hand by the edges, but if your metal is too thick or you have sweaty hands, the best option is to hold it by the middle. The heat generated by the welding process is conducted to the joints that are held in the vice grip, and this helps to transfer the heat evenly between the electrodes.
In general, a small hole or trigger is used to activate the welding process; the spot welding machine automatically comes to life once the pressure is released. You should place a piece of cardboard or foam in front of the trigger in order to create a cushion for your hands when you are preparing to weld; do not use a metallic object as a cushion. Welders work best in an atmosphere where there is little or no air noise.
When selecting a spot welding machine, consider purchasing from a manufacturer that offers a safety cover for the power supply; some manufacturers include a safety switch that automatically shuts off the power supply if the pressure is released during use. Many of the better brands offer accessories such as lead shields and holders, which help to reduce corrosion of the electrode at the contact points. The holders allow you to avoid any accidents from moisture or gas exposure. If you are welding over an existing joint, make sure that the holder matches the size of the current joint, otherwise it may overheat and melt the new joint.
If you are using a spot welding machine to weld aluminum, copper or stainless steel, remember to always weld at the correct amperage as well as the correct temperature. You can test amperage and temperature using a piece of paper or a multimeter; verify that you have enough amperage and current to conduct the metal. It is important to always pay attention to these two factors to ensure maximum quality.