Direct Conclusion: For most arc spray work, 2.0mm zinc wire is the practical standard because it balances deposition rate, coating finish and feeder compatibility. 1.6mm zinc wire is better for flame spray, thin steel and smoother coating work. 3.17mm zinc wire is used for heavy arc spray coating where higher build-up speed is more important than surface smoothness.
When you choose zinc wire diameter, do not check wire size alone. We suggest confirming spray method, coating thickness, substrate thickness, feed roll groove, contact tip size, wire tolerance and spool packing before shipment. These details directly affect feeding stability, arc stability and coating uniformity.
Zinc wire diameter should be selected according to spray method, coating thickness, substrate thickness and feeder setup. In our workshop experience, 2.0mm zinc wire is the most practical size for regular arc spray coating. 1.6mm zinc wire is easier to use for flame spray, thin steel and smoother coating surface. 3.17mm zinc wire is mainly used when higher deposition rate is needed and the feeder has enough pulling power.
Zinc Wire Diameter Overview Table
| Parameter | 1.6 mm (14 ga) | 2.0 mm (12 ga) | 3.17 mm (10 ga) |
|---|---|---|---|
| Typical deposition rate arc spray | 2–3 kg/hr | 4–6 kg/hr | 10–14 kg/hr |
| Typical deposition rate flame spray | 1–2 kg/hr | 2–3 kg/hr | 4–6 kg/hr |
| Coating finish | Fine / smooth | Medium | Rough / textured |
| Recommended min. coating thickness | 80 μm | 100 μm | 150 μm |
| Feed system requirement | Standard | Standard | High-torque feeder |
| Best for spray method | Flame spray | Arc spray general | Arc spray heavy |
| Wire per spool DIN 340 | ~1200 m / 20 kg | ~800 m / 20 kg | ~320 m / 20 kg |
Arc Spray vs Flame Spray - Diameter Recommendations
Arc Spray
In electric arc spray, two zinc wires are fed into the gun and melted by an electric arc. The feed rate must be precise to maintain a stable arc:
- 2.0 mm - the most widely used diameter for general arc spray work. It fits most common arc spray systems after checking feed roll groove, contact tip size and guide tube size. It gives a practical balance between deposition rate, coating finish and operating cost.
- 3.17 mm - not the first choice for standard flame spray work. The wire mass is larger, so complete melting depends on gun capacity, gas setting and atomizing air. We suggest using it only when the equipment manual clearly allows this diameter.
- 1.6 mm - less common in arc spray. Suitable for small-area coating, touch-up work and lower heat input to the substrate.
Flame Spray
In powderless flame spray, a single zinc wire is fed through a flame and atomized by compressed air:
- 1.6 mm - the preferred diameter. Uniform melting in the flame produces finer droplet sizes and smoother coatings.
- 2.0 mm - used when higher deposition is needed with larger flame spray guns, such as Metco 12E and 14E.
3.17 mm - rarely used in flame spray. The wire mass is too large for complete melting in standard flame spray equipment.
Diameter Tolerance Standards
Diameter tolerance means the allowable variation from the nominal diameter. It directly affects feed consistency. Two common tolerance classes exist:
| Tolerance Class | Variation | Suitable For |
|---|---|---|
| Commercial ±0.05 mm | ±0.05 mm | Hand feeding, low-speed flame spray |
| Precision ±0.02 mm | ±0.02 mm | Arc spray, high-speed automated systems |
For arc spray applications, ±0.02 mm tolerance is strongly recommended. Larger diameter variation may cause wire speed fluctuation, unstable arc and uneven coating thickness. For our zinc wire for thermal spray, we check wire diameter by micrometer or online diameter measurement, and we use OES testing for chemical composition verification.
Feedability - Why Consistent Diameter Matters
Feedability refers to how smoothly and consistently wire travels through the feed conduit, guide tube and contact tip. Even small diameter variations can become feeding problems:
- Undersize wire - skips in the feed roll groove, causing inconsistent feeding and arc fluctuation
- Oversize wire - jams in the contact tip or guide tube, causing birdnesting and downtime
- Variable diameter or lobing - causes feed speed oscillation and affects coating thickness uniformity
A ±0.02 mm tolerance helps keep stable wire-to-feed-roll contact pressure and stable feeding. This is especially important for robotic and automated thermal spray cells, because feed interruptions can cause costly rework. Our wire drawing process is monitored continuously, and each production batch is tested before release.
Diameter Selection by Substrate Material
The base material and its thickness also affect diameter choice. Based on our experience supplying thermal spray wire for corrosion protection projects, we recommend:
- Thin steel sheet < 3 mm - 1.6 mm to reduce heat input and distortion risk
- Structural steel 3–20 mm - 2.0 mm is the standard choice
- Cast iron - 2.0 mm with lower current setting to reduce thermal stress cracking risk
- Heavy steel > 20 mm - 3.17 mm for higher productivity
- Aluminum - 1.6 mm to avoid burn-through
Custom Diameters - Minimum Order Quantities
While 1.6 mm, 2.0 mm and 3.17 mm cover most thermal spray applications, we also supply custom diameters for specialized equipment, including 1.2 mm for micro-spray and 2.5 mm for specific OEM guns. Minimum order quantities for custom diameters typically start at 500 kg per size.
FAQ
Q:What is the most popular zinc wire diameter?
A:2.0 mm, or 12 AWG, is the most popular diameter worldwide. It offers a practical balance of deposition rate, coating quality and equipment compatibility.
Q:Does diameter affect coating porosity?
A:Yes. Smaller diameters such as 1.6 mm produce finer droplets and may help form denser coatings with lower porosity. Larger diameters produce coarser droplets and faster build-up. The right choice depends on your coating specification.
Q:Can diameters be switched without changing feeder parts?
A:Not always. Feed rolls, contact tips and guide tubes are usually diameter-specific. Switching from 2.0 mm to 1.6 mm may require smaller contact tips and feed roll groove inserts. Switching to 3.17 mm may require a high-torque feed motor.
Need Help Choosing Zinc Wire Diameter?
We supply 1.6 mm, 2.0 mm and 3.17 mm zinc wire for thermal spray, with diameter tolerance, spool packing and MTC support confirmed before shipment. If you are not sure which diameter fits your spray gun or feeder, send us your equipment model, coating thickness and spool requirement.
Our team can help check whether 1.6 mm, 2.0 mm or 3.17 mm zinc wire is more suitable for your arc spray or flame spray process.
Send Equipment Specs for Wire Selection
