Discontinuities and size of the weld deposit are affected by many factors. Magnetic arc blow is one of the factors that one may not be aware of. Magnetic arc blow was studied in this research with the ground position and welding current were varied. The discontinuities and size of the weld deposit were observed and measured by taking specimens of the carbon steel of AISI 1021 welded by TIG welding process using argon as protective gas. Macro photographs and data of the size of the weld deposit show magnetic arc blow has strong influence on the size of the weld on the first cut section. This specimen was welded by using 200 Ampere with the ground placed in the starting point of the welding process. Undercut and incomplete penetration are commonly found as discontinuities in all cut sections of the specimens. While porosities occur mainly in the first section with high current. It 's believed that these discontinuities occur due to the lack of shielding by the protective gas caused by very strong arc blow around the melt. Tungsten inclusions are also the common discontinuities to take place, they are found more when welding using high current (200 A). Their occurrence is because of the melting of the tip of the tungsten electrode caused by the high heat input.. At the end of the weld, crater and spatter are always found. Backward arc blow are very strong at the end of the process that arises these defects.