How Long Will an Old Welding Rod Keep?

Storing Rods

• Welding rods in their original hermetically-sealed factory container will keep indefinitely in dry, room-temperature storage. Welding rod flux coatings are hygroscopic, meaning they readily absorb water from the atmosphere. Once the container is opened, the welding rods’ coating starts absorbing atmospheric moisture. If welding rods are exposed to the air for a long enough period, their flux coating will absorb enough moisture to alter operating characteristics and impair weld quality.

Flux Coating

• The flux coating on a welding rod is made of silica, cellulose or sodium compounds that burn in the electric welding arc, producing vapors that keep atmospheric hydrogen, oxygen and nitrogen from contaminating the weld. But if the flux has absorbed too much moisture, it will generate its own hydrogen and oxygen contamination from the water in the flux. The moisture also will flash into steam that can create bubbles in the weld, weakening it.

Hot Storage

• Depending on the level of atmospheric humidity, a welding rod out of its sealed container could suffer moisture impairment in anywhere from a few hours to a week. In professional welding shops, welding rods taken out of their original container are kept in hot storage to keep moisture at bay. To combat moisture absorption, welding shops store their factory-fresh rods in dry, insulated cabinets heated to between 120 degrees and 250 degrees Fahrenheit and in relative humidity under 60 percent until they are used. Storing rods in a freezer or refrigerator won’t stop moisture absorption. Only hot storage will keep welding rods properly dry.

Baking Rods

• If welding rods have absorbed too much moisture, they can be restored to factory moisture levels by baking them in ovens. The damp rods are warmed to about 200 degrees Fahrenheit for one to two hours, then transferred to a baking oven where they are baked for about an hour at a temperature between 400 and 800 degrees Fahrenheit, depending on the type of welding rod. This baking drives out all excess moisture. A welding rod normally can be redried up to three times by baking. Rods with blistered or crumbling flux coatings generally are discarded. Partially used rods also are discarded.