The Harris 308 Stainless Steel TIG GTAW Welding Rod (part number 0308T30) is an austenitic stainless steel filler metal classified ER308 per AWS A5.9/A5.9M, offered in a 1/16 in (1.6 mm) diameter, 36-inch cut length, 10 lb box format. ER308 provides a nominal 18–20% chromium and 9–11% nickel composition that matches the chemistry of 304 and 308 stainless steel base metals — the workhorse grades of fabricated stainless equipment. Harris Products Group, a Lincoln Electric company, manufactures this rod with consistent lot chemistry and mechanical properties, providing certified C/C documentation suitable for ASME and AWS code applications. The 1/16 in diameter is the most versatile stainless TIG rod diameter, bridging light-gauge sheet work (10–14 gauge) and medium-wall piping and plate applications up to 3/8 in with a single filler size, making it the staple diameter for production TIG shops and job shops alike.
Compared to ER308L, standard ER308 allows slightly higher carbon content (≤0.08% versus ≤0.03%), which can provide marginally higher tensile strength in the as-welded condition but reduces resistance to sensitization (intergranular corrosion) if the weld zone is subsequently heated into the sensitization temperature range (800–1500°F). For most shop-temperature service applications and where welds are not re-heated, ER308 is fully acceptable. For applications requiring maximum corrosion resistance, particularly in chemical, food-grade, or post-weld heat-treated assemblies, ER308L is the preferred choice. Many welders stock both and select based on the engineering specification or drawing note.
| Attribute | Value |
|---|---|
| AWS Classification | ER308 (AWS A5.9/A5.9M) |
| Harris Part Number | 0308T30 |
| Diameter | 1/16 in (1.6 mm) |
| Cut Length | 36 in (914 mm) |
| Package Weight | 10 lb box |
| Carbon Content (max) | 0.08% |
| Chromium Content | 19.5–22.0% |
| Nickel Content | 9.0–11.0% |
| Manganese | 1.0–2.5% |
| Silicon | 0.30–0.65% |
| Tensile Strength (as welded) | ≥80,000 psi (551 MPa) |
| Yield Strength (as welded) | ≥57,000 psi (393 MPa) |
| Elongation (as welded) | ≥35% |
| Polarity | DCEN (Direct Current Electrode Negative) |
| Shielding Gas | 100% Argon or Ar/He blends |
| Process | GTAW (TIG) |
| Base Metals | 304, 308, 321, 347 stainless steels |
| Vendor | Harris Products Group (Lincoln Electric company) |
The 1/16 in diameter Harris ER308 TIG rod is the go-to size across a wide range of stainless welding applications:
- Structural Stainless Fabrication: Angle brackets, frames, support structures, and enclosures fabricated from 10–14 gauge 304 stainless sheet use the 1/16 in diameter for a balanced deposition rate and manageable filler consumption per joint.
- Stainless Pipe & Tube Work: Schedule 10S and Schedule 40S pipe in 1/2 in to 2 in NPS sizes, as well as instrumentation tubing, are routinely welded with 1/16 in ER308 rod. The diameter provides adequate fill on root and cap passes without over-depositing on thin-wall material.
- Commercial Kitchen Equipment: Sinks, countertops, dishwasher frames, prep tables, and storage racks in 304 stainless. Production TIG welding in commercial kitchen fabrication shops most commonly stocks 1/16 in ER308 as the primary filler.
- Exhaust Manifolds & Automotive Stainless: Performance exhaust systems and headers in 304 stainless use ER308 rod for smooth TIG welds with good appearance and adequate strength at moderate exhaust temperatures (below 1500°F continuous).
- Repair & Maintenance: Field repair of 304 stainless tanks, vessels, and enclosures; weld-in patches on corroded sections; filling pin holes on investment castings. The 1/16 in diameter is versatile enough for both fill passes and sealing passes.
- Water Treatment & Municipal Infrastructure: Stainless pipe fittings, valve bodies, and manifolds in potable water treatment systems; the large 10 lb box supports extended production runs.
Setting up correctly for stainless TIG welding with 1/16 in ER308 rod delivers clean, consistent beads with minimal spatter and excellent fusion:
Polarity: DCEN (Direct Current Electrode Negative). Set your TIG welder to DC mode, electrode negative. Do not use AC — AC is for aluminum TIG with pure tungsten. DCEN provides a focused, penetrating arc ideal for stainless.
Amperage Range: 80–150 amps for most 10 gauge–3/16 in stainless applications. Use a foot pedal for variable control. For 14 gauge sheet, start at 80–95 A and modulate down near tacks. For 3/16 in plate, you can run 130–150 A with confident travel speed to prevent hot cracks from excessive heat input.
Tungsten Electrode: Use 3/32 in 2% ceriated or 2% lanthanated tungsten. Grind to a sharp point with the grinding marks running lengthwise along the electrode axis (not circumferentially). This promotes a stable, columnar arc. Keep a dedicated tungsten grinding wheel for stainless to prevent cross-contamination.
Gas Setup: 100% argon at 18–22 CFH through a gas lens cup (size 6 or 8 recommended). A gas lens diffuser provides laminar flow and superior shielding coverage compared to standard collet body assemblies — essential for bright, unoxidized stainless weld beads. For root passes on pipe, back-purge with 100% argon at 3–8 CFH to prevent sugaring on the inside surface.
Parameter Table for ER308 1/16 in:
| Material Thickness | Amperage | Tungsten | Cup Size | Ar Flow CFH |
|---|---|---|---|---|
| 14 gauge (0.078 in) | 75–100 A | 3/32 ceriated | #6 | 18 |
| 12 gauge (0.109 in) | 100–125 A | 3/32 ceriated | #6 | 18–20 |
| 3/16 in (0.188 in) | 130–160 A | 3/32–1/8 ceriated | #7–8 | 20–22 |
| 1/4 in plate | 160–190 A | 1/8 ceriated | #8 | 22–25 |
Technique Tips: Keep the tungsten 1/8 in off the base metal; do not touch tungsten to weld pool. Feed rod at a low 10–15° angle to the weld pool, maintaining the rod tip inside the argon shielding cone at all times to prevent rod-tip oxidation. Move at a steady pace — stainless dissipates heat slowly and will build up, causing discoloration or carbide precipitation if travel slows. Allow each pass to cool to hand-warm (below 150°F) before adding the next pass on multi-pass welds.
- Dry Storage Required: Store 308 TIG rods in the original sealed box in a temperature-controlled location (40–120°F). Moisture on the rod surface causes porosity and erratic arc starts, especially on root passes where shielding is most critical.
- Stainless-Dedicated Storage: Keep stainless TIG rods completely separate from carbon steel or iron-containing materials. Even trace iron contamination causes rust spots that compromise weld corrosion resistance.
- Handle with Clean Gloves: Skin oils and chloride-containing perspiration on stainless filler rod can introduce chloride ions to weld metal — particularly problematic in marine and chemical service. Use nitrile or cotton gloves when handling.
- Certificate of Conformance: Each 10 lb box of Harris 308 TIG rod is traceable to a specific melt heat number. Retain the C/C documentation if welding to ASME, AWS, or other code requirements. The C/C provides the chemistry and mechanical test data required for WPS and PQR qualification records.
- Shelf Life: Properly stored, stainless TIG rods have an indefinite shelf life. If rods develop surface discoloration from marginal storage conditions, inspect for pitting — superficial tarnish can typically be cleaned with stainless wire brush before use.
Harris ER308 1/16 in TIG rod is compatible with any standard DC TIG welding machine:
- Lincoln Electric Square Wave TIG 200 (K5126-1): Compact AC/DC TIG welder ideal for shop and light fabrication ER308 work. The pulse function helps manage heat on production stainless work.
- Lincoln Electric Invertec V155-S: Rugged DC-only TIG machine for maintenance and field stainless repair using ER308.
- Lincoln Electric Precision TIG 225 / 275: Higher-amperage platforms for heavier plate and pipe work with ER308 rod in the 3/16 in–1/4 in thickness range.
Compatible Base Metal Combinations:
| Base Metal | ER308 Compatibility | Notes |
|---|---|---|
| AISI 304 / 304H | ✅ Primary | Most common stainless; ER308 and ER308L are both acceptable |
| AISI 308 | ✅ Direct match | Chemistry matches — ideal |
| AISI 321 | ✅ Acceptable | For non-elevated-temp service; use 347 rod for high-temp |
| AISI 347 | ✅ Acceptable | Acceptable for general service applications |
| AISI 302 | ✅ Acceptable | Slightly higher carbon base; ER308 works for non-sensitization-critical service |
| AISI 316 (general service) | ✅ Acceptable | ER308 acceptable; ER316L preferred in aggressive environments |
| Carbon steel to stainless (dissimilar) | ❌ | Use ER309L for carbon-to-stainless dissimilar joints |
ER308 is the foundational austenitic stainless TIG classification, and selecting between ER308 and its variants requires understanding the base metal composition, service conditions, and code requirements of the application.
ER308 per AWS A5.9/A5.9M specifies: C ≤0.08%, Cr 19.5–22.0%, Ni 9.0–11.0%, Mo ≤0.75%, Mn 1.0–2.5%, Si 0.30–0.65%. The 1/16 in (1.6 mm) diameter covers the broadest thickness range: thin-sheet automotive trim to medium-wall tubing and pipe in a single diameter.
ER308 is AWS-approved for welding the following wrought and cast austenitic grades:
- AISI 301, 302, 304, 305 — matching Cr-Ni chemistry; standard structural and fabrication use
- AISI 308 plate and pipe — matching classification by definition
- AISI 347 (Nb-stabilized) — ER308 acceptable for most welding procedures; ER347 for critical high-temp service
- AISI 321 (Ti-stabilized) — ER308 acceptable for general welding; ER321 or ER347 preferred for sustained high-temp service above 800°F
- CF-8 and CF-8C cast stainless — ASTM A351 castings; ER308 provides compatible deposit
Properly balanced ER308 deposit contains 4–12 FN (Ferrite Number) in the as-welded condition. Ferrite content is critical for hot cracking resistance in austenitic stainless welds — fully austenitic deposits (0 FN) are prone to solidification (hot) cracking, especially in fully restrained joints. Harris ER308 is formulated to produce deposits within the 4–9 FN range, providing hot cracking resistance while maintaining corrosion resistance and low-temperature toughness.
- 14–10 gauge stainless sheet (0.075–0.135 in): Automotive exhaust fabrication, HVAC stainless ductwork, food equipment fabrication. The 1/16 in rod is the production size for sheet metal TIG in commercial fab shops.
- Pipe root passes (Sch 10, Sch 40, 1–3 in NPS): Root pass penetration on stainless pipe for process piping in food and chemical plants. 1/16 in rod provides controlled deposit volume for open-butt root passes.
- Thin-wall tube (0.049–0.083 in wall): Sanitary tubing welds for food/dairy/pharmaceutical application.
ER308 TIG deposits on 304/308 stainless require post-weld cleaning to restore corrosion resistance: (1) remove heat tint (oxidation) using stainless wire brushing plus pickling paste (10% nitric / 2% hydrofluoric acid blend) or electrolytic passivation; (2) passivate per ASTM A380 (nitric acid bath) for pressure equipment and food contact surfaces. Unpickled ER308 deposits in corrosive service environments will exhibit accelerated crevice and pitting corrosion at the heat-tinted zone.
Q1: What does ER308 mean in welding?
ER308 is the AWS A5.9 classification for stainless steel TIG (and MIG) filler wire. "E" = electrode (usable as either electrode or rod), "R" = rod (used as bare filler), "308" identifies the nominal alloy composition (18–20% Cr, 9–11% Ni, balance iron). The classification confirms the rod meets minimum chemistry and mechanical property requirements of AWS A5.9/A5.9M.
Q2: Should I use ER308 or ER308L for my application?
Use ER308L when: the finished assembly will be exposed to corrosive media, the weld zone will be re-heated (e.g., in a furnace or by subsequent welding passes), or the specification/drawing calls for "L" grade filler. Use ER308 when: the joint is in benign service, re-heating is not a factor, and the spec permits either. When in doubt, ER308L is the safer choice — it meets all the same code requirements as ER308 while offering better sensitization resistance.
Q3: Why is my ER308 stainless TIG weld discoloring (turning blue/gold/black)?
Discoloration (heat tint or oxidation) indicates inadequate argon shielding at the weld zone. Check: (1) gas flow rate — increase to 18–22 CFH, (2) gas lens installed — standard collet bodies have turbulent flow; switch to a gas lens, (3) drafts in the weld area — shield from wind or air movement, (4) trailing shielding on hot weld bead behind torch, and (5) back-purging on pipe roots. Light gold tint is minor oxidation; dark blue or black means severe inadequate shielding and the weld should be evaluated for intergranular corrosion risk in critical service.
Q4: What shielding gas is correct for ER308 stainless TIG?
100% argon (commercial or high-purity grade, 99.997% minimum) at 18–22 CFH is the standard. Argon/helium blends (75/25 Ar/He) increase arc voltage and heat input — useful on heavier plate to increase travel speed. Never use argon/CO₂ mixtures for stainless TIG — CO₂ reduces the weld metal and introduces carbon, defeating the purpose of the stainless filler.
Q5: Can ER308 be used to repair 316L stainless equipment?
For general-service repair where the equipment sees temperatures below 800°F and moderate corrosive conditions, ER308 is acceptable on 316L base metal as a temporary or permanent repair. For equipment handling chloride-containing media, seawater, or operating above 800°F, specify ER316L rod for the repair to preserve molybdenum content and pitting resistance.
Q6: What amperage should I run for 1/16 in ER308 TIG rod?
For most applications, 80–150 amps DCEN. On 14 gauge sheet, 80–100 A with a foot pedal gives good control. For 3/16 in plate, 130–160 A with a confident travel speed. Always use a foot pedal for stainless TIG if available — stainless builds heat quickly and amperage control prevents weld cracking, discoloration, and warpage.
Q7: Is a 10 lb box the right quantity for my project?
At roughly 1/16 in diameter and 36 in length per rod, a 10 lb box contains approximately 110–120 individual rods. For a production run welding Schedule 10 pipe fittings or light sheet metal assemblies, a 10 lb box lasts a skilled welder through several hundred joint-inches of 1/16 in rod work. For a single job-shop project, a 2 or 5 lb tube may be more economical. WeldingMart also stocks the 5 lb tube option (308LT305) for smaller quantity needs.