MIG welders handbook: how to become a more skilled welder and how to select the best welding equipment. Just about everyone who tries TIG welding feels challenged at first. This is understandable, given all the things you have to watch for and think about, while simultaneously coordinating the motion of both hands. In most cases, a foot pedal or torch-mounted amperage control will be used — for starting, modulating and stopping the flow of current. I have coached many people as they learn these skills, and I have received my share of questions over the years. Here are a few frequently asked questions — and answers — that should be helpful, particularly for beginning and intermediate welders.
One of the “cardinal sins” that almost every shop commits is over-welding. This means that if the drawing calls for a 1/4″ fillet weld, most shops will put down a 5/16″ weld. The reasons? Either they don’t have a fillet gauge and are not exactly sure of the size of the weld they are producing or they put in some extra to “cover” themselves and make sure there is enough weld metal in place. But, over-welding leads to tremendous consumable waste. Let’s look again at our example. For a 1/4″ fillet weld, the typical operator will use .129 lbs. per foot of weld metal. The 5/16″ weld requires .201 lbs. per foot of weld metal – a 56 percent increase in weld volume compared to what is really needed. Plus, you must take into account the additional labor necessary to put down a larger weld. Not only is the company paying for extra, wasted consumable material, a weld with more weld metal is more likely to have warpage and distortion because of the added heat input. It is recommended that every operator be given a fillet gauge to accurately produce the weld specified – and nothing more. In addition, changes in wire diameter may be used to eliminate over-welding.
Several advices on welding equipment, MIG and TIG welders, plasma cutters. Welders with a higher power output can work with thicker metals, but higher voltage welders will require special power supply set ups-either generators or appropriate power outlets. A welder with lower voltage in the 100’s will not be able to handle heavy duty jobs, but it can be plugged in and operated from any outlet. Any welder with power over 200 cannot run off a typical power outlet and will naturally cost more to run. In addition, welders will either run an alternating current (AC) that reverses itself at regular intervals or a direct current (DC) that flows in one direction and does not reverse itself. DC offers a steady rate of energy that leads to hotter temperatures and deeper weld penetration. AC welders usually cost less than DC welders, but the available electrodes are far more limited for AC. In fact, DC welders are more costly but remain popular because their higher power offers a wider selection of electrodes and a number of working advantages such as: simple arc striking, better penetration, and improved control. Welders who expect to work on a wide variety of projects may want to consider an AC/DC combination welder.
The welding setup, welder settings, and electrode selection will impact how fast welders can work. Industrial welders invest time in planning the size and shape of their welding areas, how parts are laid out, and how they supply their shielding gas. Testing settings or an electrode on a piece of scrap metal, especially for a beginners, will save time in the long run. Learn more about setting up an efficient shop here. Welding Downhill Increases Welding Speed: While welding downhill is a faster way to weld, it’s not as strong as welding uphill. On most projects it’s not worth sacrificing strength and durability for the sake of welding speed. However, if the metal is thin enough, then welding downhill won’t make the weld weaker and may even be the correct technique for the job. Learn about uphill and downhill welding and see these diagrams of vertical and downhill welding. See additional details at MIG Welding Machines.
Put a vent hole in anything you weld that will be sealed up completely: Put a vent hole in anything you weld that will be sealed up completely or air will heat up and expand and blow away your shielding gas or even blow out at the end of the weld bead. Some machined joints that are sealed on one end will not even allow you to start welding because the fit is so good that the part is air tight before you even weld. Other machined parts where a part is pressed in and bottomed out can give cracking problems because there is no where for the part to shrink. If you have to weld something that has been pressed in and bottomed out, make sure to add more filler metal than average to tacks and the final weld bead. That is to prevent the cracking that happens when you run a concave bead and the metal has nowhere to shrink.