Hello Root Pass, first a question or two. Have you done much open root GTAW tig roots? Having the proper root/joint configuration set-up is fairly important, knife-edge, ultra-clean and smooth, consistent and proper gap, correct filler selection and diameter. Torch set-up, correct cup size, proper tungsten selection, proper tungsten grind, proper tungsten stick-out, manual on/off gas valve. The machine should be set for straight polarity, in other words, connect the torch assembly to the - side of the output on the welder and the ground to the + side of the welder output. Generally, you have to select a particular amperage and experiment some to get the correct heat to put in a successful root pass, at the same time that you select an amperage setting you have to be very consistent with your speed of travel, rod feed angle, and any other variables that can influence groove penetration. I purposefully didn't list a lot of the specifics as there are many different preferences for performing open root, scratch-start welds. If you have an opportunity, try to find someone who will allow you to observe this type of work being done, as in most instances, seeing it done can speak volumes towards learning it. Possibly, even better yet, if you have access to any training facilities, see about signing up for some instruction on how it's done. One of the biggest things to succeeding at this is: PRACTICE, PRACTICE, PRACTICE. Please forgive me if you are already aware of everything that I have said here, I do not know your level of experience or knowledge. With some attention to detail, a fair amount of practice, and the right equipment and set-up parameters you will be cranking out those root passes right and left on your good old SA200. Good luck and regards, aevald
Forum
