Selecting the right filler metal - GTAW ER70S-3
If you are looking for a disappointing first welding experience, buy the ER70S-3 for filler metal. The ER70S-3 wire is often referred to as having a "moderate" deoxidizer content. In reality by comparison, this is really little or none. The question of course comes immediately to mind, “Why use it?” The answer is that it is really economical to use, especially if you have exceptionally clean metal. ER70S-3 is among the cheapest wires to buy. Its primary use is in the fabrication industry where there is time taken to fully clean the steel. The low deoxidizer content also means that little slag will be formed on top of the weld, so more than likely a second pass can be made without so much as brushing the weld before the next one is made. However, if rust or other contamination is present, the weld will result in a dark, dull weld that may have porosity or a “burned” look to it. And as far as wetting in, good luck trying to force that blob of metal on the end of the rod to cooperate. For the beginner, it will be hard to achieve a satisfactory looking weld. For the experienced TIG welder, the welds will still occasionally have a less than perfect appearance to them. If you have the time to thoroughly clean and prep the metal and want to save money, then the 70S-6 may be something worth considering. But, most people would rather skip this rod and go for either a 70S-2, or a 70S-6 and lightly brush the weld afterwards. Yes, it’s economical, and widely available, but beware, you may bite of more than you can weld with this welding rod.