What is Hot Air Welding

Hot Air Welding: Introduction

Hot air welding, also known as hot gas welding, is a popular technique that has been used for decades in a variety of industries including automotive, roofing, signage, and more. This method involves heating the thermoplastic material to its melting point and then fusing the parts together using a stream of hot air. The resulting bond is strong and often as strong or even stronger than the original material.

In this article, I will cover What is hot air welding, including how it works, what materials it can be used on, and the advantages and disadvantages of this method.

What is Hot Air Welding?

Hot air welding, also known as hot gas welding, is a process used to join two or more thermoplastic materials (e.g, films, fabrics, PU) together using a controlled stream of heated air with high precision and welding speed.

This technique is commonly used in various industries such as automotive, roofing, and signage for the creation of strong and durable bonds.

Hot air welding

Hot Air Welding Process Working Principle

Hot air welding works by heating the plastic material to its melting point using a stream of hot air. The heat is typically generated by an electrically powered heating element, which heats the air as it passes over it. The heated air in a compressed state is injected at the welding locations to join the materials.

Once the plastic material reaches its melting point, it is pressed together and allowed to cool, creating a strong and permanent bond.

Temperature Range

The temperature range used in hot air welding typically ranges from 400°C to 750°C (750°F to 1380°F). However, the exact temperature required will vary depending on the type of plastic being welded, its thickness, and the specific welding process being used.

Time to Complete a Weld

The time it takes to complete a hot air weld will depend on various factors such as the type of plastic being welded, its thickness, the temperature being used, and the size of the welding area. Generally, hot air welding can be completed relatively quickly, with most welds taking only a few seconds to complete.

Weld Quality

Hot air welding can produce high-quality, strong, and durable welds when performed correctly. However, the quality of the weld will depend on various factors such as the temperature used, the speed at which the welding is performed, the pressure applied during the welding process, and the cleanliness of the welding surface.

When performed correctly, hot air welding can produce welds that are as strong or stronger than the original material, making it an ideal choice for a wide range of applications.

Hot Air Welding Applications

Here are some specific examples of hot air welding applications in different industries:

  1. Automotive Industry:
  • Welding plastic door panels, instrument panels, and other interior trim pieces.
  • Repairing plastic fuel tanks and radiator parts.
  • Creating and repairing plastic bumpers and body panels.
  1. Roofing Industry:
  • Welding seams on thermoplastic roofing membranes made from PVC, TPO, and other materials.
  • Sealing joints and overlaps in roofing materials to prevent water penetration.
  1. Signage Industry:
  • Welding plastic letters, logos, and frames for signs.
  • Creating plastic light boxes and displays.
  • Repairing and maintaining plastic signs and displays.
  1. Fabrication Industry:
  • Welding plastic components for tanks, containers, and ducts.
  • Repairing and maintaining plastic machine parts.
  • Welding plastic parts for agricultural equipment.
  1. Medical Industry:
  • Welding plastic components for medical devices such as blood bags, tubing, and connectors.
  • Repairing and maintaining medical equipment made from plastic.
  • Creating custom plastic components for medical equipment and devices.
  1. Food Industry:
  • Welding plastic components for food packaging such as trays, containers, and lids.
  • Creating and repairing plastic food processing equipment such as conveyor belts and cutting blades.
  • Welding plastic components for kitchen equipment such as blenders and food processors.
  1. Packaging Industry:
  • Welding plastic components for packaging machinery such as blister pack machines and filling machines.
  • Sealing and welding plastic packaging materials such as bags, pouches, and tubes.
  • Repairing and maintaining plastic packaging machinery and equipment.
Hot Air Welding Video

What materials can be welded with Hot Air Welding?

Here are some thermoplastic materials that can be welded using hot air welding:

  1. Polyvinyl chloride (PVC),
  2. Polyethylene (PE),
  3. Polypropylene (PP),
  4. Thermoplastic olefins (TPO),
  5. Acrylonitrile butadiene styrene (ABS),
  6. Polycarbonate (PC),
  7. Polyurethane (PU),
  8. Ethylene-vinyl acetate (EVA),
  9. Chlorinated polyethylene (CPE),
  10. Polyvinylidene fluoride (PVDF).

Do hot air welders use filler rod?

Hot air welders typically do not use filler rod. The hot air welding process involves using heated air to melt the thermoplastic material, creating a strong bond between the two surfaces being welded.

This process is often referred to as “fusion welding,” as the material on each side of the joint is melted and fused together to create a single piece.


What types of thermoplastic materials can be welded using hot air welding?

Hot air welding can be used to join a variety of thermoplastic materials, including polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), thermoplastic olefins (TPO), and acrylonitrile butadiene styrene (ABS), among others.

Can hot-air welding be used to repair damaged thermoplastic parts?

Yes, hot-air welding can be used to repair damaged thermoplastic parts by melting the damaged area and fusing it back together. This can be a cost-effective and efficient method for repairing damaged parts without having to replace them.

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