DISCLAIMER. This document was presented in International Conference on Design & Application of Engineering Materials (ICDAEM) and Seminar Nasional Metalurgi dan Material (SeNaMM) in Institut Teknologi Bandung, 2018. This document and all the contents are free for educational use with attribution to the authors. Complete bibliography is listed on https://drive.google.com/file/d/1inX2ufF9M9XLDuX0pmTuniQMCNSkC5nx/view?usp=sharing .Some of them was not uploaded on the presentation unintendedly. ABSTRACT. In wet tropical climate regions, ambient water vapor tends to be rapidly picked up by welding electrode flux. Arc contaminated by hydrogen derived from the damp flux will increase risk of defects in welded joint, especially hydrogen cracking. In this work, weldability of AISI 1035 steel is studied based on modified Welding Institute of Canada (WIC) Test and variation of moisture picked-up by AWS A5.1 E6013 electrode in a conditioned atmosphere. On the third day after welding, surface crack was examined using dye penetrant technique. In consequence of no preheat implemented, solidification cracking occurred along 37% of the weld length although the flux was dried with 0% absorbed moisture relative to the flux weight, whereas more severe crack was found 48% on the sample welded using damp electrode with 7% absorbed moisture due to solidification and diffusible hydrogen. Preheat at 150°C reduced the risk of cracking which did not present on the sample welded by electrode containing 0% and 1.42% absorbed moisture, but 3% crack still appeared on the sample welded using electrode having 1.83% absorbed moisture because of hydrogen contribution. As the one of analysis result, preheating at 150°C and 1.42% maximum absorbed moisture in the flux is recommended for the E6013 electrode.