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Fabricating stainless steel drip trays is a good job for TIG welding, but it is less forgiving than it looks. The material is often thin, the corners need to be watertight, and contamination can leave pinholes or rust-colored marks around the weld. A suitable welder gives you control, but fit-up, shielding gas, and heat management matter just as much.
For most trays made from 18- to 20-gauge stainless sheet, a 200-amp DC TIG welder is the practical target. You do not need a huge industrial machine. You do need stable low-amp control, high-frequency start, a usable foot pedal, and enough torch and gas equipment to work comfortably.
What to Look for in a TIG Welder
Stainless steel uses DCEN (direct current electrode negative), so an AC function is not required. AC is useful for aluminum, but it adds cost without improving a stainless drip tray. Spend that money on torch quality, a foot control, or a better gas regulator instead.
| Feature | Why it matters for drip trays | Practical target |
|---|---|---|
| Output range | Controls thin sheet without making the machine difficult to use | 5–200 amps DC |
| High-frequency start | Starts the arc without touching tungsten to the stainless | Preferred |
| Foot pedal or remote amperage | Lets you reduce heat at corners and the end of a weld | Strongly recommended |
| Pulse control | Helps manage heat and limit distortion on thin sheet | Useful, not essential |
| Gas pre-flow and post-flow | Protects the tungsten and hot weld from air | Adjustable controls |
A basic 200-amp DC TIG welder with foot pedal is enough for most home and small-shop tray work. Check what is included. Some machines advertise TIG capability but include only a scratch-start torch, with no HF start, pedal, regulator, or proper work lead.
The Best TIG Welder Types for This Work
200-amp inverter DC TIG welder
This is the best all-around choice. Inverter machines are compact, efficient, and generally offer the low-current control needed for thin stainless. Look for a machine that can weld steadily below 10 amps. A 200-amp rating gives useful headroom for heavier brackets or thick corners, while the inverter’s duty cycle is usually adequate for small trays.
For a single tray, a lower-cost inverter is fine if it has HF start and stable arc control. A machine with a 20% duty cycle at 200 amps may still be perfectly serviceable because thin stainless is normally welded at roughly 35 to 75 amps. The rating becomes a concern when making long continuous welds or fabricating multiple trays all day.
AC/DC TIG welder
Choose AC/DC if you also weld aluminum, not because stainless requires it. These machines often provide better pulse and sequencing controls, but the price increase can be substantial. If your work includes aluminum pans, brackets, or heat exchangers, an AC/DC TIG welder can be the more economical long-term purchase.
Scratch-start or lift-start TIG
These are acceptable for occasional repairs, but they are a poor first choice for clean stainless fabrication. Touching the tungsten to the work can transfer contamination and leave a starting mark. Lift-start is better than scratch-start, but HF start is easier to use and produces cleaner starts on visible surfaces.
Recommended Settings for Stainless Steel
For 20-gauge stainless, start around 35 to 50 amps. For 18-gauge material, 45 to 70 amps is a useful starting range. Actual settings depend on the joint, fit-up, tungsten size, and whether you are welding a corner or a flat seam. Use a 1.6 mm (1/16-inch) 2% lanthanated tungsten, sharpened to a long taper, and a small cup such as #6 or #7.
Use 100% argon at approximately 15 to 20 cubic feet per hour. Excessive flow can create turbulence and draw air into the shield, so more gas is not automatically better. Set post-flow for roughly 5 to 8 seconds; the tungsten should remain covered until it stops glowing.
A pulse setting of 1 to 2 pulses per second with a moderate background current can help reduce heat input, but pulse is not a substitute for speed. On very thin sheet, a continuous weld can still overheat the panel. Tack the tray frequently, alternate sides, and weld short sections rather than trying to run one uninterrupted bead.
Gas Purge and Contamination Control
If the tray must hold liquid, the visible weld is only half the problem. The back side of a stainless joint can oxidize heavily when it is exposed to air while hot. This “sugaring” creates a rough, dark surface that can trap residue and may eventually leak. For butt joints or fully penetrated seams, back-purge the inside with argon.
A simple purge setup uses a low-flow regulator, aluminum tape, and temporary fittings to contain gas inside the tray. Start with roughly 5 to 10 cubic feet per hour and provide a small vent so pressure does not push the weld out. A TIG back-purge kit is useful when making repeated enclosed parts, although improvised dams work for occasional fabrication.
Keep stainless-only brushes, flap wheels, and files for the job. Carbon-steel contamination can produce rust spots after cleaning. Wipe the joint with acetone or an appropriate solvent, let it dry, and avoid touching the cleaned area with dirty gloves.
Fit-Up and Welding Technique
Good fit-up saves more stainless than higher amperage. Aim for a tight, consistent joint with little or no gap. A large gap forces you to add filler and increases heat input. For thin tray walls, 308L filler is common when welding 304 stainless; 316L filler is appropriate when the base material is 316. Match the filler to the material and service rather than choosing by diameter alone.
Use 1.0 mm or 1.6 mm filler for light sheet. Make tacks about 25 to 40 mm apart, then check that the tray is still square before filling between them. Keep the arc short, add only enough filler to form a smooth seam, and wash the puddle from one tack to the next. If the sheet turns blue, brown, or badly distorted, you are putting in too much heat.
Corner joints are common leak points. Do not grind a pinhole closed and assume it is fixed; clean the area, remove the oxidized metal, and re-weld it with proper shielding. After welding, inspect with a bright light and test the tray with water. For critical containment, use a dye penetrant inspection rather than relying only on a visual check.
Accessories Worth Buying
Budget for a proper regulator and flowmeter, a flexible torch, spare 1.6 mm tungsten, stainless filler rod, gas lenses, and a foot pedal. A gas lens often gives a smoother shield and makes it easier to extend the tungsten slightly into corners. A TIG gas lens and tungsten kit is a sensible upgrade over the small standard collet body supplied with many entry-level machines.
Also use a clean stainless-compatible work surface and clamp the sheet firmly. Stainless expands and contracts noticeably during welding, so poor fixturing can turn a flat tray into a twisted one. The best-value welder is the one that provides controlled starts and low-amp stability; the rest of the result comes from clean material, tight joints, and disciplined heat control.