Wire Flame Spray Guns: Complete Guide to Operation, Applications, Benefits & Working Principle (2025 Edition)

Thermal spray technology has grown rapidly across industries such as engineering, steel, automotive, mining, textile, and oil & gas. Among all thermal spray methods, Wire Flame Spray stands out as one of the most economical, simple, and reliable metal coating processes used worldwide.

A Wire Flame Spray Gun uses heat from a fuel gas (Propane/LPG or Acetylene) mixed with Oxygen to melt a metal wire—typically 3.15 mm—and propel molten droplets onto the component surface. This forms a strong, dense, and corrosion-resistant coating.

If you are new to flame spray or looking to understand how these guns work, this detailed guide will walk you through:

• What is Wire Flame Spray?

• How does a flame spray gun work?

• Propane vs LPG vs Acetylene usage

• Suitable wire materials (3.15 mm)

• Applications across industries

• Advantages of flame spray

• Required equipment and setup

• Safety guidelines

• Why Balaji Udyog flame spray guns are trusted worldwide

What Is Wire Flame Spray?

Wire flame spray is a thermal spray coating process where a metal wire is continuously fed into a spray gun. A fuel gas (Propane/LPG or Acetylene) and Oxygen create a high-temperature flame that melts the wire. Compressed air then atomizes and accelerates the molten metal onto the work surface.

The result is a strong, functional metal coating that protects parts from:

• Wear

• Corrosion

• Erosion

• Heat

• Friction

Wire flame spray is widely used because it is:

• Affordable

• Mechanically simple

• Easy to maintain

• Suitable for large areas

• Capable of high-bond coatings

How Does a Wire Flame Spray Gun Work? – Step-By-Step

Here is the simplified working principle:

1. Fuel Gas + Oxygen Mixing

The gun receives fuel (Propane/LPG or Acetylene) from a cylinder and Oxygen from another cylinder.
These gases mix inside the gun and create a controlled, high-temperature flame at the nozzle.

2. Metal Wire Feeding

A 3.15 mm diameter metal wire (Zinc, Aluminum, Stainless Steel, Nickel, Bronze, etc.) is inserted into the wire feeding assembly.
A drive mechanism pushes the wire towards the flame at a controlled speed.

3. Melting of the Wire

As the wire enters the flame, it melts instantly due to the high temperature.

• Propane/Oxygen flame temperature ≈ 2800°C

• Acetylene/Oxygen flame temperature ≈ 3100°C

This makes the process suitable for a wide range of metals.

4. Atomizing and Spraying

Compressed air breaks the molten metal into tiny droplets and accelerates them towards the substrate.

These molten particles impact the surface and flatten, forming:

• A mechanically bonded

• Strong

• Uniform

• Protective
  coating layer.

5. Layer Formation

Multiple passes build the coating thickness as required:

• Typical thickness: 50–500 microns

• Heavy-duty coatings: 1–2 mm depending on material

Fuel Options for Flame Spray Guns

Your gun supports all major fuel combinations:

1. Propane + Oxygen (Most Common)

• Clean burning

• Economical

• Easy availability

• Stable flame

• Suitable for general coatings (Zinc, Aluminum, Bronze)

2. LPG + Oxygen

• Similar to propane

• Often cheaper in industrial markets

• Lower flame temperature than acetylene

• Excellent for corrosion prevention coatings (Zn/Al)

3. Acetylene + Oxygen

• Highest flame temperature

• Best for high-melting-point wires

• Produces finer spray

• Ideal for repair coatings, mild steel, stainless steel

This versatility is a major reason Balaji Udyog Flame Spray Guns are used globally.

Wire Materials Used in 3.15 mm Size

The most common wire diameter for flame spray is 3.15 mm, due to stable feeding and consistent melting.

Popular wire materials:

Wire MaterialApplicationZinc (Zn)Anti-corrosion coatings for pipelines, tanks, structuresAluminum (Al)Marine protection, heat-resistant coatingsAluminium BronzeWear-resistant coating for pumps, shaftsCopperElectrical and conductive coatingsStainless SteelHigh wear parts, chemical resistanceMolybdenumHigh-friction surfaces, automotive componentsNickel & Nickel-AlloysHigh-temperature and corrosion-resistant usesBronzeBearing repair, pump sleeves

The combination of 3.15 mm wire and propane/oxygen flame gives maximum performance with minimum cost.

Applications of Wire Flame Spray Coating

Wire flame spray is used in almost every engineering field. Below are the most important industries:

1. Automotive Industry

• Transmission shafts

• Piston rings

• Clutch plates

• Brake components

• Wear sleeves

2. Steel & Rolling Mills

• Zinc coating for rollers

• Bronze coating for continuous casting rolls

• Repair of worn shafts

3. Marine Industry

• Aluminum coatings for ship decks

• Anti-corrosion for offshore equipment

4. Oil & Gas

• Protection against corrosion & saltwater

• Pump parts

• Valves and sealing surfaces

5. Engineering & Maintenance Repairs

• Build-up worn shafts

• Pump sleeves

• Motor housings

• Bearings and journals

6. Textile & Printing

• Hard coat for rollers

• Ceramic-based composite layers

7. Heavy Machinery

• Restoring tolerances on large components

• Repair instead of replacement (cost saving 60–80%)

Because the equipment is portable, flame spray guns are also widely used for on-site coating jobs.

Why Choose Wire Flame Spray? – Key Benefits

1. Cost-Effective

Among all thermal spray processes (HVOF, Plasma, Arc Spray), wire flame spray is the most economical in terms of:

• Equipment cost

• Gas consumption

• Wire cost

• Maintenance

2. Easy to Operate

Technicians can learn to operate the gun within hours. No advanced software or electronics are needed.

3. Portable and Versatile

Can be used inside workshops or directly on-site at:

• Bridges

• Tanks

• Pipelines

• Large steel structures

4. Excellent Coating Adhesion

Coatings bond mechanically and provide:

• Strong grip

• Dense structure

• Long-term protection

5. Wide Range of Materials

From zinc to stainless steel, many coating materials can be used depending on application.

6. Repairing Worn Parts

Rather than replacing expensive parts, flame spray allows engineers to:

• Rebuild

• Restore

• Strengthen

the damaged surfaces.

7. Minimal Heat Transfer

Surface temperature remains low (below 150°C), so there is:

• No distortion

• No structural change

• No metallurgical damage

This makes it safe for delicate materials and thin components.

Equipment Required for Wire Flame Spray

To operate a flame spray gun, you need:

1. Wire Flame Spray Gun (Balaji Udyog 12M Model)

2. Fuel Gas Cylinder (Propane/LPG or Acetylene)

3. Oxygen Cylinder

4. Gas Regulators

5. Hoses (Oxygen, Fuel & Air)

6. Air Compressor (Minimum 4–5 bar)

7. Metal Wire (3.15 mm)

8. Surface Preparation Tools

   • Grit blaster

   • Grinder

   • Cleaning solvents

Our guns support all standard fittings and are compatible with most wires in the market.

Surface Preparation – The Secret to Strong Coatings

Coating performance depends heavily on surface preparation.
Before spraying:

1. Cleaning

Remove oil, rust, paint, and dust.

2. Grit Blasting

Using Aluminum Oxide or Grit, achieve a roughened surface with:

• Anchor Profile: 50–80 microns (typical)

• Cleanliness: SA 2.5

This rough profile allows molten particles to mechanically lock into the surface.

3. Pre-Heating (if required)

Some materials require mild warming to remove moisture.

Safety Guidelines for Flame Spray Gun Operation

Working with oxygen and fuel gases requires strict safety precautions.

1. Personal Protective Equipment

• Safety goggles

• Flame-resistant clothing

• Leather gloves

• Respirator mask

• Hearing protection

2. Gas Handling

• Always use certified gas regulators

• Check hoses for leaks

• Secure cylinders upright

• Never use oil/grease near oxygen systems

3. Operational Safety

• Maintain proper ventilation

• Keep fire extinguishers nearby

• Avoid spraying near flammable materials

• Do not point the gun at any person

Following these guidelines ensures safe, smooth, and reliable coating performance.

Why Choose Balaji Udyog Wire Flame Spray Guns?

Your image shows one of the Balaji Udyog Wire Flame Spray Guns (12M-136/12M-135 models) in action—designed for industrial-duty use with precision engineering.

Key Features:

• Compatible with 3.15 mm wires

• Runs on Propane/LPG + Oxygen or Acetylene + Oxygen

• Heavy-duty wire feed mechanism

• Stable flame and efficient melting

• Smooth air atomization for perfect coating

• Lightweight and ergonomic design

• Long-life nozzles and spare parts available

• Robust metal body for industrial environments

Advantages of Balaji Guns

• High reliability

• Affordable spare parts

• Low maintenance requirement

• Long operating life

• Easy availability of consumables

Our guns are widely used in:

• Workshops

• Industrial plants

• Thermal spray contractors

• Maintenance & repair service providers

Conclusion

Wire Flame Spray remains one of the most powerful and economical thermal spray processes in the world. Whether you need corrosion protection, wear resistance, or part rebuilding, a reliable flame spray gun using 3.15 mm wire and Propane/Oxygen or Acetylene/Oxygen offers outstanding performance.

With the right equipment—like Balaji Udyog’s Flame Spray Guns—industries can achieve long-lasting, high-quality coatings while keeping operational costs low.

If you are in need of:

• Flame spray guns

• Thermal spray equipment

• Spare parts

• Coating guidance

you can always contact Balaji Udyog, a trusted name in thermal spray technology.