What's inside
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Repairing a steel water trough is usually a short weld in an inconvenient place. The practical challenge is controlling heat on thin, rust-thinned sheet without leaving a pinhole or burning the surrounding steel away. For most farm repairs, a small DC stick welder with adjustable output is a better choice than a large industrial machine. But the welder is only part of the decision: steel thickness, access, and how cleanly you can drain and prepare the trough matter just as much.
What the job demands
Many troughs are made from sheet steel around 14 to 12 gauge—roughly 1.9 to 2.7 mm thick—though older or heavily corroded ones may be thinner at the leak. Stick welding can repair this material, but it is less forgiving than MIG at low amperage. Too much heat, a long arc, or a pause can open a hole. Rust, paint, galvanizing, and water contamination make the arc less predictable and can cause porosity or a weld that looks sound but leaks.
Drain the trough, let it dry, and grind back to bright metal on both sides if accessible. Remove paint and coatings well beyond the weld area; do not weld galvanized steel without removing the coating and using suitable ventilation. If the leak sits in paper-thin, deeply pitted metal, a new patch may simply burn through the surrounding sheet. A larger patch that reaches solid steel, or replacing the trough, may be the more reliable fix.
What to buy
Look for a DC inverter stick welder with a usable low end around 20–30 amps and a maximum output in the 100–140 amp range. A machine that starts and maintains a steady arc at low current is more useful here than one advertised with a very high maximum amperage. A 120-volt model is convenient for basic repairs; 120/240-volt input gives more headroom for thicker patches and other work, but costs more and needs a suitable 240-volt supply to deliver its full output.
For thin trough steel, 1/16-inch (1.6 mm) electrodes are often easier to manage than larger rods. A 3/32-inch (2.4 mm) rod can work on sound, thicker areas, but its higher current and larger puddle make burn-through more likely. Use an electrode suited to the steel and the machine; 6013 is commonly used for light fabrication and can be easier for occasional welders to control, while 7018 generally asks for cleaner preparation and more careful handling. Follow the rod manufacturer’s current range and keep low-hydrogen rods dry as directed.
Compare 120-volt DC inverter stick welders for occasional repairs, or consider a dual-voltage stick welder if you will also weld thicker stock. Check the manual for input-current requirements and duty cycle, not just the maximum output printed on the case.
Welder types compared
| Option | Best fit | Trade-off |
|---|---|---|
| 120 V DC inverter stick | Small, occasional trough repairs; portable farm use | Less output for thick patches, and low-voltage circuits may trip breakers |
| 120/240 V inverter stick | One machine for thin repairs and heavier steel | Costs more; full output depends on a proper 240 V supply |
| Basic transformer stick welder | Low-cost work on thicker material | Usually heavier and less adjustable at the low end needed for thin sheet |
| MIG welder | Frequent thin-sheet repairs in a sheltered work area | Needs wire, shielding gas or flux-core setup, and protection from wind |
A basic transformer unit can be perfectly adequate if it is already on hand and the repair is on thicker, sound steel. It is a less attractive purchase specifically for thin troughs, where a stable low setting and small electrode make the work easier. MIG is often easier to control on thin sheet, but outdoor wind can disrupt shielding gas, and flux-core wire tends to make more spatter and cleanup.
How to weld the patch
Cut a patch from steel close to the trough’s thickness, with rounded corners to reduce stress concentrations. Fit it tightly over or behind the damaged area; large gaps make burn-through more likely. Tack opposite sides first, then add short welds of about 1/2 inch (12 mm), alternating locations so one spot does not overheat. Let the metal cool between passes. A continuous bead is tempting, but on thin sheet it can distort the trough or turn a small leak into a long split.
Use the shortest stable arc you can maintain, and keep moving. If the puddle starts to sag or the edges glow, stop and let the steel cool. Slag and spatter can hide pinholes, so chip and brush the weld before inspecting it. Avoid striking an arc on the trough’s water-contact surface away from the repair: stray arc strikes can create hard spots and future corrosion points.
After the metal has cooled, check the repair for visible pinholes and test it with water before putting the trough back into service. If the weld will be exposed to drinking water for livestock, confirm that the repair materials and any coating are appropriate for that use. Paint or seal only after the weld is clean and sound; coating over a leaking or contaminated joint will not fix it.
Accessories and safety
Budget for a properly rated welding helmet, gloves, and flame-resistant clothing, plus a grinder and wire brush for preparation. An auto-darkening helmet is convenient, but shade rating and a reliable lens matter more than extra settings. Keep the work area dry, remove nearby combustible bedding and feed, and have a fire extinguisher within reach. Never weld a container that has held fuel or other flammable material; a water trough is not a sealed vessel, but still check for trapped gases or coatings before striking an arc.
A properly rated auto-darkening welding helmet is a useful convenience for repeated tack-and-stop work. If the trough is badly rusted, the repair location is inaccessible, or the sheet burns through repeatedly at a sensible low setting, stop adding weld metal. At that point, a larger patch tied into sound steel—or replacement—is usually safer and less frustrating than chasing the leak around the tank.