The Harris 00SIBF2 is an ERCuSi-A classified silicon bronze MIG wire — a copper-silicon alloy engineered for GMAW braze welding, surfacing, and dissimilar metal joining. Packaged as a 0.035 in (0.9 mm) diameter, 2 lb spool, it is ideal for hobbyist, auto-body, and light industrial shops that need a small-format spool for silicon bronze mig processes. Harris Products Group, a Lincoln Electric company, produces this silicon bronze alloy to AWS A5.7 ERCuSi-A specifications. WeldingMart.com is an authorized Harris distributor.
Silicon bronze MIG wire produces a low-spatter, low-heat input bronze deposit that excels on coated sheet steels, galvanized steel, thin-gauge steel, and cast iron. The silicon (2.8–4.0%) acts as a deoxidizer in the weld pool, producing clean, porosity-free deposits, while the copper base provides corrosion resistance and excellent flow characteristics ideal for mig brazing silicon bronze applications.
| Specification | Value |
|---|---|
| AWS Classification | ERCuSi-A (AWS A5.7/A5.7M) |
| Harris Part Number | 00SIBF2 |
| Diameter | 0.035 in (0.9 mm) |
| Package | 2 lb (0.9 kg) spool |
| Cu content (typical) | Balance Cu |
| Si content | 2.8–4.0% |
| Mn content | 1.5% max |
| Tensile Strength | ≥ 50,000 psi (345 MPa) |
| Elongation | ≥ 20% |
| Polarity | DCEP |
| Shielding Gas | 100% Ar or 98% Ar / 2% O₂ |
| Process | GMAW (MIG braze welding) |
Full chemistry and mechanical data available at harriswelding.com. AWS A5.7 is published by the American Welding Society.
- Braze welding coated sheet steels: MIG brazing galvanized, zinc-coated, and aluminized sheet steel with minimal burn-through and preserved coating integrity around the joint.
- Auto body and thin gauge steel: Silicon bronze mig wire deposits at lower temperatures than steel wire, minimizing distortion on 18–22 gauge body panels.
- Welding brass and copper: Joining copper base metals, brass fittings, and bronze castings with a matching-chemistry filler that resists dezincification.
- Cast iron repair: Braze welding gray cast iron and ductile iron components without preheating to the high temperatures required by steel electrodes, reducing cracking risk.
- Dissimilar metal applications: Joining steel to copper, copper to bronze, and similar composition base metals in electrical, HVAC, and marine assemblies.
- Artistic and decorative fabrication: Producing bronze-colored welds on structural steel assemblies, railings, and ornamental work.
Silicon bronze MIG wire runs best at low voltage and wire feed speed settings — often 15–20% lower than a comparable steel wire setup. The goal is braze welding: the bronze wets the base metal rather than fully fusing it, minimizing distortion on thin coated sheet steels.
| Parameter | 0.035 in ERCuSi-A Typical Range |
|---|---|
| Shielding Gas | 100% Ar (preferred) or 98% Ar / 2% O₂ |
| Flow Rate | 25–35 CFH |
| Polarity | DCEP |
| Wire Feed Speed | 150–250 IPM |
| Voltage | 17–22 V |
| Current (typical) | 80–150 A |
| Transfer Mode | Short-circuit (preferred for thin gauge) |
| Base Metal Prep | Clean to bare metal or tight-adherent coating |
Use 100% argon shielding. CO₂ additions oxidize the silicon in the bronze alloy, producing excessive slag and reducing weld quality. A short arc length (1/4 in contact-tip-to-work) maintains stable short-circuit transfer. Use a slightly forehand angle (5–10°) and keep travel speed consistent to achieve even wetting and a flat bead profile.
Store silicon bronze wire in a cool, dry location at 40–120 °F. The copper-silicon alloy is less hygroscopic than aluminum wire but still sensitive to contamination. Best practices:
- Keep spools in sealed packaging until use; reseal unused portions
- Use Teflon or nylon MIG gun liners — copper alloy wire is soft and sheds particles in steel liners
- Clean drive rolls regularly; bronze wire is softer than steel and can groove V-groove rolls
- Use knurled V-groove or flat-knurled drive rolls designed for soft wire
- Avoid storing near chemicals, solvents, or saltwater environments that accelerate tarnish
Harris 00SIBF2 ERCuSi-A runs on any CV GMAW power source rated for 0.035 in wire. Low-amperage MIG machines including the Lincoln Power MIG 180C and Power MIG 215 MP are appropriate for 18–22 gauge panel work using silicon bronze. For production and heavier applications, the Power MIG 256 or Power Wave series with synergic pulse programs provides excellent arc control. Use Teflon-lined MIG guns for best wire feeding; steel-lined guns develop rapid wear and produce contaminating ferrous fines in the bronze deposit.
Shielding gas: 100% Argon is the standard choice for silicon bronze mig brazing. See also Harris Silicon Bronze MIG Wire 0.025 in 10 lb, Harris Silicon Bronze 0.045 in 30 lb Spool, and all welding wire.
- What is silicon bronze MIG welding wire used for?
- ERCuSi-A silicon bronze MIG wire is used primarily for mig brazing silicon bronze onto thin steel, galvanized sheet, cast iron, and copper base metals. It runs at lower heat than steel wire, preserving coatings on galvanized steel while producing corrosion-resistant, low-spatter bronze deposits.
- Can silicon bronze wire weld cast iron?
- Yes. Braze welding gray cast iron and ductile iron with ERCuSi-A is a proven technique that avoids the high preheat (500–1200 °F) needed for steel electrodes on cast iron. The bronze wets the iron surface without creating a hard, brittle HAZ. This makes it suitable for cast iron repair on machine components, automotive housings, and ornamental ironwork.
- What shielding gas do I use with silicon bronze MIG wire?
- 100% Argon is the standard and preferred shielding gas. A 98% Ar / 2% O₂ blend is acceptable but will slightly increase slag formation. Never use CO₂-rich blends (C25, C100) — CO₂ oxidizes the silicon in the alloy, degrading weld quality significantly.
- Is ERCuSi-A the same as silicon bronze?
- Yes. AWS ERCuSi-A is the specification designation for silicon bronze filler metal — a copper-silicon alloy with 2.8–4.0% silicon. "Silicon bronze" is the common trade name. "ERCuSi-A" is the AWS A5.7 classification. Both refer to the same alloy system.
- Can I use silicon bronze wire on galvanized steel?
- Yes, and it is one of the primary applications. The low heat input of silicon bronze MIG brazing minimizes zinc vaporization compared to steel GMAW. Zinc burns off with fumes; always weld galvanized steel with adequate ventilation. The bronze deposit bonds to the galvanized surface and provides its own corrosion barrier at the joint.
- What drive rolls should I use with silicon bronze MIG wire?
- Use U-groove (round-groove) or smooth V-groove drive rolls sized for 0.035 in wire. Avoid knurled rolls designed for flux-cored wire — they will shave the soft copper-silicon alloy and create wire feeding issues and contamination in the liner.
- What is the difference between silicon bronze MIG wire and steel MIG wire?
- Steel MIG wire (ER70S-6) fuses with the base metal at 2,600 °F+ and produces steel deposits. Silicon bronze wire (ERCuSi-A) braze-welds at ~1,900 °F, wetting the base metal surface without full fusion. This means lower heat input, less distortion, preserved zinc coatings on galvanized steel, and a copper-colored deposit. Steel wire is stronger; silicon bronze is better for thin coated steels, dissimilar metals, and cast iron.
The 0.035 in silicon bronze mig wire is the most versatile option in the Harris silicon bronze mig line. It is useful to check your MIG machine's minimum amperage capability before ordering — silicon bronze runs best at the lower end of the machine's output range. For braze welding on coated sheet steels, the thanks-to-silicon deoxidizing reaction means no added flux is required. When customers buy this silicon bronze mig wire product, they frequently also check the availability of 0.025 in fine-diameter wire for ultra-thin panels and 0.045 in wire for production work. The website listing shows that 00SIBF2 is the 2 lb spool option — ideal for low-volume shops that have changed to silicon bronze for occasional cast iron, copper, and dissimilar metal work without investing in a full 30 lb production spool.
The Harris 00SIBF2 ERCuSi-A silicon bronze MIG wire at 0.035 in diameter covers the widest range of MIG brazing applications in the silicon bronze product line — thin sheet body work, medium-gauge structural braze welding, copper and brass joining, and cast iron repair all fall within the operating envelope of this diameter. At 80–150 A with 100% argon shielding, the 0.035 in wire delivers consistent short-circuit transfer deposits on 18–20 gauge coated sheet and short-circuit to spray transition on thicker gauge structural components.
Modern automotive plants use silicon bronze MIG brazing (ERCuSi-A) to join roof panels to B-pillars and A-pillars on galvanized steel vehicle structures. The process choice over resistance spot welding or steel MIG is driven by:
- Roof-to-body-side joint access: The external seam between the roof stampings and upper body rails is continuous — not accessible for spot welding. MIG brazing runs the full joint length in one pass, sealing the joint against water ingress and providing structural continuity.
- Zinc coating integrity: Galvanized panel coatings adjacent to silicon bronze braze joints remain intact for 20–50 mm from the joint centerline, whereas steel MIG fusion welding burns zinc for 80–150 mm on each side, creating corrosion-prone bare zones.
- Paintability: Silicon bronze braze beads are smooth, low-crown, and respond identically to automotive paint chemistry as the surrounding steel — no special primer or corrosion protection treatment required at the braze joint.
| Application | Voltage | WFS | Current (est.) | Mode |
|---|---|---|---|---|
| 18–22 gauge thin sheet (panels) | 16–18 V | 150–200 IPM | 80–110 A | Short-circuit |
| 16–18 gauge structural sheet | 18–21 V | 200–260 IPM | 110–140 A | Short-circuit |
| Lap fillet on 14-gauge | 21–23 V | 240–290 IPM | 130–160 A | SC or transition |
| Cast iron cosmetic repair | 17–20 V | 180–240 IPM | 100–130 A | Short-circuit |
| Copper joining (14 gauge) | 19–22 V | 200–270 IPM | 120–150 A | Short-circuit |
The key variable is shielding gas purity. Even a 5% argon drop (substituting 95/5 Ar/CO₂ for 100% Ar) produces visible arc instability and spatter increase with silicon bronze MIG wire. Carbon dioxide reacts with the silicon in ERCuSi-A alloy, generating silica (SiO₂) that floats to the weld surface as slag. In production applications, a contaminated argon cylinder or faulty regulator manifold commonly causes sudden quality drops in silicon bronze MIG brazing stations.
When silicon bronze MIG braze welds join two different base metals, galvanic corrosion at the joint is a consideration in wet or marine service. ERCuSi-A deposits fall galvanically between copper and steel in the electrochemical series:
- Silicon bronze on galvanized steel: Low galvanic potential difference. Bronze (cathodic) and zinc coating (anodic) have a modest potential difference — acceptable in most architectural and automotive service. The zinc coating adjacent to the joint provides cathodic protection to the bare steel at the joint edge.
- Silicon bronze on bare carbon steel: Bronze is cathodic to steel — steel corrodes preferentially in electrolyte. This is acceptable for indoor structural applications but not for marine service without coating. Always paint or coat silicon bronze braze joints used in outdoor wet environments.
- Silicon bronze on copper: Minimal galvanic difference — both are copper alloys. ERCuSi-A on copper provides excellent galvanic compatibility for plumbing, HVAC, and electrical applications.
- Silicon bronze on cast iron: Iron is anodic to bronze — iron corrodes slightly at the interface in wet service. For cast iron repair in dry indoor environments (engine housings, machine frames), this is not an issue.
Harris 00SIBF2 is the 2 lb spool format, ideal for body shops and small fabrication operations. For production and heavier applications, see Harris Silicon Bronze 0.045 in 30 lb spool. For ultra-thin sheet applications, see Harris Silicon Bronze 0.025 in 10 lb spool.
The features silicon bronze alloy ERCuSi-A provides over steel wire include lower heat input for welding base metals like galvanized steels, coated sheet steel, and cast iron. When welding a similar composition of copper-silicon to copper brass components, the ERCuSi-A filler provides close chemical compatibility. Silicon bronze also joins copper brass fittings and brass plumbing components where pre heat depending on brass thickness prevents cracking — require pre heat on brass sections over 3/16 in thick to avoid thermal shock in the zinc-rich copper brass base metal.
For welding base metals like galvanized steels, the silicon in the alloy acts as a deoxidizer that keeps the weld pool clean even when zinc vapor from the galvanized coating enters the arc zone. The welding alloy deposits a bronze layer that bonds metallurgically to galvanized steels. Thickness of base metal determines voltage and wire feed speed settings — thinner gauge requires lower voltage to avoid burn-through on coated sheet steels. For similar composition base metals (copper-to-copper, bronze-to-bronze), the silicon bronze alloy provides excellent flow characteristics and wettability, creating a copper content-matched joint that resists corrosion and galvanic attack.