Longtime viewer Buck Leach stops by Kevin’s studio and asks what welding pulse is and why you might care. With pulse, a welder takes the working amperage and spikes it to your welding amperage and then back down again to where you have set it. It does this in milliseconds. It can be set to go as slowly as every couple of seconds – your setting is based upon the thickness of the metal, the type of metal and even where you are welding.
Kevin says he’s used pulse when welding overhead because it helps the welding puddle “freeze” slightly, cooling it down. Playing with the variables and the machine’s controls helps you figure out what you can do.
Kevin then shows what the pulse looks like in AC as it spikes, then drops down to a negative, then comes back up to positive again. He reminds Buck that he’s not an electrical engineer, but this is what he’s learned when studying pulse online. In DC, you have a pulse up to your welding amperage or voltage, depending upon your welder, and a pulse back down to 0 or whatever you have the machine set at. So it gets hot, then gets cold, letting the metal cool down instead of building up too much heat and blowing through it.
The pulse can be set to kick in every few seconds to as many as 250 pulses a second on some machines. The latter is so fast you can hear it but not see it. Kevin points out that, if you’re welding for a living, how you will set your welder will probably be spelled out for each project.
Kevin then explains that, although nearly every TIG welder today has pulse in one form or another, pulse also is used with MIG. He also has, unintentionally, even gotten pulse to work on an arc welder (also known as a stick welder) that is included on a TIG welder he has. Even though he was able to weld with it, he is not aware of any application for pulse with arc, especially because the rods require such a narrow range of working amperage.
Next they go over to Everlast’s POWERTIG 255EXT, one of Everlast’s newer TIG welders. For example, Kevin would, for 1/8″ plate steel, weld at 115 to 135 amps, then set the pulse at a percentage of that. So if the working amperage were set at 125 amps, and he had his pulse set at 50 percent, it would go down to 62 amps at its lowest point. Kevin explains that the newer welders seem to run on percentage, while older machines required you to set the actual amperage itself. The percentages make it easier, though, for the welder’s computer.
Back at the machine’s control panel, Kevin sets the pulse frequency – which is how often you want the welder to pulse – the AC balance (because he’s been welding in AC on his latest sculpture, which is aluminum), which is not an issue when welding steel, and AC frequency, again because he is welding in AC.
This Everlast TIG welder, also has something called Advanced Pulse, which, when you’re welding in AC, provides a postive AC to clean and a negative DC to weld. They are switching between AC and DC while you are welding! That’s the inverter, the computer and all those chips at work. This allows you to drop the amperage a lot because you’re getting so much more power out of the DC spike. The positive AC spike cleans the oxide off of the aluminum, then the DC negative spike penetrates the metal so you can weld it. Then it goes back to AC again to clean some more. So with 16 gauge aluminum, on regular AC, he’d run the machine at about 70 amps. If he uses the Advanced Pulse, he turns it down to as low as 35 – 40 amps. The result: no warping, because you aren’t putting all that extra heat into it.
Pulse is great with thin metal – Kevin says you could actually weld two soda cans together with this machine. Its strengths in welding thin metal make pulse especially applicable for the food industry, health care, aircraft and aerospace, as well as the automobile world.