Low-hydrogen rods and the tin they came in

Low-hydrogen electrodes exist to keep hydrogen out of the weld. The flux coating that achieves it is hygroscopic — it absorbs moisture from the air — which makes storage part of the consumable, not an afterthought.

The mechanism

Moisture in the flux dissociates in the arc. Atomic hydrogen dissolves into the molten weld pool, then comes out of solution as the weld cools and concentrates at the heat-affected zone. Under restraint, that causes delayed cracking — often twenty-four to forty-eight hours after welding, long after the job has been inspected.

Handling

• Buy vacuum-packed tins and open them at the job, not at goods-in.
• Once opened, a heated quiver at 70 to 120C is the correct storage. A toolbox is not.
• Exposure limits are on the label and are measured in hours, not days.
• Re-dry to the manufacturer schedule — typically around 300 to 350C for an hour or two. A domestic oven cannot do this.

If rods have been loose in a van through a wet winter, they are scrap. That is cheaper than a cracked structural weld.

Written for Arcline Welding Supplies — a demonstration store. See the AgenticEcom Suite.