Welding flux redrying oven

The re-drying oven removes moisture from the welding flux. If you process moist flux, you get hydrogen into the weld metal, which causes cold cracks. So: always store flux dry and re-dry it in the oven according to the specifications before use. Make sure the temperature and drying time are correct and the oven is clean. If the flux clumps or is no longer free-flowing, it's no good and you throw it away.