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What Is Hot Gas Plastic Welding?

PE100/HDPE Plastic Sheets in Fuel Tank Fabrication

What Is Hot Gas Plastic Welding?

Hot gas plastic welding is a technique used to join two or more pieces of thermoplastic materials together. It involves heating the plastic surfaces to a molten state using hot air or a gas stream, then pressing them together to form a strong bond.

The heat softens the plastic, allowing the molecules to become intermingled and fused together as they cool and solidify.

The process typically involves using a handheld welding gun or a welding machine that generates a controlled flow of heated air or gas. The temperature of the hot gas is carefully regulated to ensure that it is sufficient to melt the plastic but not so high as to cause degradation or burning.

During hot gas plastic welding, the operator directs the heated gas stream onto the plastic surfaces to be joined, melting them and creating a molten pool.
The softened plastic is then pressed together, allowing the molten material to mix and bond. Pressure is applied to ensure proper contact and fusion between the plastic pieces.
Hot gas plastic welding is commonly used in various industries, such as automotive, construction, and manufacturing, for applications like repairing plastic parts, fabricating plastic components, or sealing plastic sheets.

It is a versatile and efficient method for creating strong and durable plastic joints.

Here at Poly Synthesis, we specialise in thermoplastic fabrications from tanks to pipes, and everything in between!


Which gases are commonly used for Hot Gas Plastic welding?

The most commonly used gases for hot gas plastic welding are air and nitrogen.

Air is readily available and typically used in most hot gas plastic welding applications. The air is heated by a heating element within the welding gun or machine and directed onto the plastic surfaces to be joined.

Nitrogen is another gas often used for hot gas plastic welding. Nitrogen has the advantage of being an inert gas, meaning it does not react with the plastic material being welded.
This can be beneficial for certain sensitive or reactive plastics, as it helps prevent oxidation or degradation during the welding process.

In some specialised applications, other gases such as argon or carbon dioxide may also be used depending on the specific requirements of the plastic material and the desired welding results.
These gases can provide different heat transfer characteristics or protective atmospheres to ensure optimal welding conditions.

The choice of gas for hot gas plastic welding depends on factors such as the type of plastic being welded, the desired welding temperature, the need for an inert atmosphere, and the equipment available.


Is plastic welding hot work?

Yes, hot gas plastic welding is considered a form of hot work as it involves the use of a heated air or gas stream to melt and fuse the plastic surfaces.

Hot work refers to any process or operation that involves open flames, sparks, or heat-generating tools or equipment.

Because of the heat involved, it is essential to take appropriate safety precautions when performing hot gas plastic welding.
This may include wearing protective gear such as heat-resistant gloves, goggles, and clothing, as well as ensuring proper ventilation in the working area to dissipate any fumes or gases generated during the process.

Additionally, it is important to be mindful of the potential fire hazard associated with hot work.
Adequate fire prevention measures, such as having fire extinguishers nearby and following proper safety protocols, should be in place to mitigate any risks.


What are the advantages of hot gas welding?

Hot gas welding offers several advantages making it a preferred method for joining thermoplastic materials.

Some key advantages of hot gas welding include:
Strong and Durable Joints: Hot gas welding creates robust and long-lasting joints. The process allows for the fusion of plastic surfaces, resulting in a homogeneous bond that exhibits good mechanical strength.
Versatility: Hot gas welding is suitable for a wide range of thermoplastic materials, including polyethylene, polypropylene, PVC, ABS, and more. It can be used to join different types of plastics together or repair plastic components.
Cost-Effective: Hot gas welding is a relatively cost-effective method compared to other plastic welding techniques. The equipment required for hot gas welding is generally affordable and readily available.
High Precision: Hot gas welding enables precise control over the heat and welding parameters, allowing for accurate and controlled melting of the plastic surfaces. This precision contributes to consistent and high-quality welds.
No Additional Materials Required: Unlike some other plastic joining methods, hot gas welding does not typically require the use of additional consumables, adhesives, or fasteners. It relies solely on heat to achieve the fusion of plastic surfaces, reducing the need for additional materials.
Aesthetic Appearance: When performed correctly, hot gas welding can result in aesthetically pleasing joints. The welded area can have a smooth finish, blending seamlessly with the surrounding plastic material.
Efficiency: Hot gas welding is a relatively fast welding process, allowing for efficient production or repair of plastic components. It enables rapid heating and cooling cycles, minimising downtime and increasing productivity.
Environmentally Friendly: Hot gas welding is a clean process that does not involve the use of adhesives or solvents, reducing the emission of harmful substances. It is a more environmentally friendly option compared to methods that rely on chemical bonding agents.

In summary, Hot gas welding is a widely used method for joining thermoplastic materials. It offers several advantages, including strong and durable joints, versatility in working with different types of plastics, cost-effectiveness, high precision, and a visually appealing finish!

Reach out to the Poly Synthesis team today or book in an appointment with one of our specialists for all your engineering and industrial plastic needs!




By Sharnie

Sharnie Aitken is the Owner and Director of Poly Synthesis Pty Ltd, a plastic fabrication company in Brisbane, Australia. View his LinkedIn profile here: www.linkedin.com/in/sharnie-aitken

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