2008年7月28日 · Miller Thunderbolt xl AC/DC 07-28-2008, 10:03 PM whats up everyone iam new to the site, i have a miller thunderbolt xl ac/dc model i know i can tig weld with carbon steel with it, but my question is can i weld S.S. with it also i use the negative mode around 90 amps on it whats the diffrence with the posotive mode, can any one help me well ...