Low-Hydrogen Electrode Storage and Baking Guide
Low-hydrogen electrodes like E7018, E7018-1, and E7016 are the most moisture-sensitive consumables in welding. Their flux coatings are designed to deposit very little hydrogen in the weld, which prevents cracking in thick sections and high-strength steels. But this only works if the rods stay dry. Moisture absorbed into the coating releases hydrogen during welding, defeating the entire purpose of using a low-hydrogen rod.
Why Moisture Matters
Hydrogen is the smallest atom. It dissolves easily into molten steel and can migrate through the heat-affected zone after the weld cools. In thick sections or high-strength steels, this dissolved hydrogen causes delayed cracking, sometimes called cold cracking or hydrogen-induced cracking (HIC). Cracks may not appear for hours or days after welding.
Low-hydrogen electrodes have coatings formulated to keep diffusible hydrogen below specific thresholds. H4 means 4 mL or less per 100g of weld metal. H8 means 8 mL or less. The R suffix (as in H4R) means the coating resists moisture absorption better than standard rods. But even H4R rods will absorb moisture if left exposed long enough.
Storage Requirements
Unopened hermetically sealed cans can be stored at room temperature for years. The seal prevents moisture ingress.
After opening, rods must go into a rod oven set at 250-300F (120-150C). This is non-negotiable for code work. Many shops keep a rod oven running continuously and pull rods as needed.
Maximum atmospheric exposure depends on the hydrogen designation. H4R rods can be out of the oven for up to 4 hours before they need reconditioning. H8 rods allow 9 hours. Standard (non-R) H4 rods may allow only 1-2 hours.
Reconditioning Procedures
If rods have been exposed to moisture beyond the allowed time, they must be reconditioned (baked) before use.
Standard reconditioning: 700F (370C) for 1 hour. This drives out absorbed moisture from the coating.
Maximum reconditioning cycles: Most manufacturers allow 1-3 reconditioning cycles. After that, the coating chemistry may degrade and the rods should be discarded.
Never recondition in a kitchen oven. Most kitchen ovens do not reach 700F reliably, and the fumes from electrode coatings are not food-safe.
Practical Tips
If you are a hobbyist who only welds occasionally, buy 7018 in small sealed containers (1-5 lb). Use what you need and discard the rest rather than investing in a rod oven.
For job sites, portable rod ovens that hold 10-20 lbs are available from Lincoln, Phoenix, and others. They run on 120V and keep rods at proper holding temperature.
If you suspect moisture contamination, look for porosity in test welds. Scattered gas pores in the weld bead are a telltale sign of hydrogen from wet rods.
The cost of a rod oven is far less than the cost of a cracked weld on a structural connection.
Classification system defined by AWS A5.1, Lincoln Electric, ESAB technical bulletins.