1. The coating of coated electrodes absorbs moisture when exposed to the atmosphere for a long period of time or when exposed for moderate or short period to moist or humid environment (e.g. welding during rainy season, near river or sea, on docks or offshore platforms, etc. where the humidity is relatively high). Moisture picked up by the electrode coating will:
a. Lead to porosity in the weld bead.
b. Cause more spatter during welding – which means extra loss of weld metal.
c. Induce more hydrogen through arc – the welded structure or job may become more susceptible to Hydrogen Induced Cracking after welding.
d. Weaken the adherence of the coating with core wire – during welding when the “end” section of remaining length of electrode becomes hot , the coating may peel off in small pieces, which can lead to porosities, slag inclusions, etc.
e. Create undercuts on sides of weld due to high arc force – this may happen if the moisture level becomes very high.