REPAIR WELDING CORRODED WATER STORAGE TANKS: WHAT TO EXPECT

Steel water storage tanks and similar vessels take a beating over time. Even with coatings, moisture, condensation, and chemicals can lead to corrosion. Around Edmonton and the surrounding acreages, you also see tanks used for irrigation, fire water storage, and industrial process water. When a tank starts leaking or thinning out, repair welding is possible, but it is not a simple patch-and-go job.

First step: confirm what you are dealing with

Before any welding happens, you need to understand the condition of the steel. Corrosion can look small on the surface but be wide underneath. A proper plan usually includes:

• Visual inspection: identify leak points, rust scale, and coating failure areas.
• Thickness checks: ultrasonic thickness testing is common to confirm how much metal is left.
• Access review: can the area be reached safely for prep, welding, and inspection?
• Service conditions: what is stored inside, and what contamination or residue is present?

If a tank has held chemicals, fuel, or unknown contents, the safety rules change fast. Venting, cleaning, and gas testing may be required. Safety is not optional on confined spaces.

Why tank repairs require serious prep

Corrosion often leaves thin, uneven steel. If you weld over thin metal without prep, you can blow through, trap contamination, or create a crack-prone repair. Good prep usually means cutting out the worst material and rebuilding with sound steel.

Typical repair approaches

• Patch plate repair: remove corroded section, fit a new plate, weld with a controlled procedure.
• Build-up and overlay: in some cases, the base metal is still thick enough and a controlled overlay is used for reinforcement.
• Nozzle and fitting repair: leaks often start at connections, where stress and corrosion meet.
• Seam repair: vertical and circumferential seams can crack if the tank has moved or settled.

Choosing the right welding process

For tank repair in the field, process choice depends on steel thickness, access, and the environment:

• MIG welding: fast and productive on clean, controllable joints. Great for patch plates and shop-style repairs.
• Stick welding: often the go-to for outdoor work, especially if wind is an issue or power access is limited.
• TIG welding: best when you need maximum control on thinner sections or stainless components.

In winter, Edmonton wind and cold steel can make shielding gas protection tougher. That is one reason stick welding is still a workhorse on many outdoor jobs.

Distortion and cracking: the two big enemies

Tanks are large, thin structures. If you dump heat into one spot, the steel moves. Poor sequencing can pull plates out of shape, create gaps, or stress the surrounding metal. A good repair plan uses tack welds, step welding, and a balanced sequence.

Finishing and leak checking

A tank repair is not complete when the arc stops. The repair needs verification. Depending on the application, that can include:

• Visual inspection: check bead tie-in, undercut, and any porosity.
• Dye penetrant testing: common on critical surface cracks.
• Leak testing: water fill, low-pressure air and soap solution, or other methods based on the tank and rules.
• Coating repair: weld areas need proper coating to prevent rapid re-corrosion.

In Alberta, corrosion is often accelerated by moisture swings and temperature changes. If you leave bare steel around a repair, the rust comes back fast. A good coating touch-up matters.

When replacement is smarter than repair

Sometimes the steel is too thin across too large an area. If thickness readings show widespread thinning, patching one spot can just move the leak to the next weak area. In that case, fabricating a new section, retrofitting with reinforcement, or replacing the tank can be the safer long-term option.

Talk to YEGWELD about a tank repair

We handle mobile welding repairs and fabrication across Edmonton and the surrounding region. If you have a tank leak, corrosion issue, or need a new fitting welded in, call 780-233-8285 or reach out through our contact page. Emergency service is available 24/7.

This article is for informational purposes only and may contain inaccuracies. Always consult a certified welding professional before starting any project.