| Process | Wire/Rod | Shield | Best For |
|---|---|---|---|
| SMAW (Stick) | E7018 / E6010 | Flux | Field structural |
| GMAW (MIG) | ER70S-6 | 75/25 Ar/CO² | Shop fabrication |
| FCAW-S | E71T-8 | Self | Field (wind OK) |
| FCAW-G | E71T-1 | 75/25 gas | Shop / sheltered |
| GTAW (TIG) | ER308L/70S-2 | 100% Ar | SS, Al, ornamental |
FCAW-S = DCEN • FCAW-G = DCEP • Wrong polarity = zero penetration.
| Diameter | Amperage | Use |
|---|---|---|
| 3/32″ (2.5 mm) | 70–110 A | Thin, root passes |
| 1/8″ (3.2 mm) | 110–150 A | General field (most common) |
| 5/32″ (4.0 mm) | 140–200 A | Flat/horizontal fillets |
| 3/16″ (4.8 mm) | 180–255 A | Flat only, heavy shop |
| Thickness | Min Preheat |
|---|---|
| Up to 19 mm | 0°C (above freezing) |
| 19–38 mm | 66°C (150°F) |
| 38–64 mm | 107°C (225°F) |
| Over 64 mm | 150°C (300°F) |
| Defect | Common Cause | Prevention |
|---|---|---|
| Porosity | Wet rods, contamination | Oven rods, clean steel |
| Undercut | Excess heat, wrong angle | Reduce amps, slow down |
| Lack of fusion | Low heat, wrong angle | More heat, proper angle |
| Slag inclusion | Poor interpass cleaning | Chip + brush every pass |
| H² cracking | Wet rods, no preheat | Dry rods, preheat per code |
| Parameter | Value |
|---|---|
| O² working pressure | 25–40 psi (cut); up to 60 psi (heavy) |
| Acetylene max | NEVER >15 psi (unstable above) |
| Preheat to | ~870°C (cherry red) before O² jet |
| Works on | Ferrous metals only |
| Amps | Quality Cut | Severance |
|---|---|---|
| 30 A | 8 mm | 12 mm |
| 45 A | 12 mm | 16 mm |
| 65 A | 20 mm | 25 mm |
| 85–105 A | 25–32 mm | 38 mm |
Plasma cuts SS + Al; oxy-fuel cannot.
| Type | DFT | Prep |
|---|---|---|
| Zinc-rich (ZRC) | 50–100 μm | SSPC-SP 11 (bare metal) |
| Alkyd / red oxide | 50–75 μm | SSPC-SP 3 (power tool) |