How to Weld Plastic?

Plastic Welding

Not only metals can be welded, but also many plastics can be joined together by the joining process. 

Plastic welding is a fabrication process used to join two or more pieces of plastic together. The pieces are joined using heat and pressure, usually from an electric tool, but sometimes through the use of solvents.

It has become an increasingly popular method of joining plastics due to its ability to create strong and durable bonds while maintaining the integrity of the material.

Plastic welding can be used in a variety of industries including automotive, aerospace and electronics.

What you need for Plastic Welding?

Plastic welding is quite different than conventional welding process. However, both conventional welding as well as plastic welding require heat to melt the welding joint and form a weld.

Whether it’s making repairs on a car bumper or constructing an entire boat, knowing how to effectively weld plastics can make the job much easier and successful. But what do you need in order to weld plastic materials?

To successfully join plastic, you need to have certain equipment and tools as listed below:

Things you need for Plastic Welding
  • ✨ A Hot-air Fan Welding Machine,
  • ✨ Welding Wire,
  • ✨ Angle Plier Cutter,
  • ✨ 180-320 Grit Sandpaper,
  • ✨ Plastic Welding Rollers,
  • ✨ Welding Nozzle,

Plastic Welding Methods

Hot air welding equipment. These devices work similarly to heat guns, but often also have the shape of a classic soldering iron.

They also reach temperatures similar to those of hot air guns (up to 600 °C). The welding process for welding machines works similarly to metal welding processes, here too welding wire is usually used.

Adhesive welding systems. These systems are a special, very strong adhesive. In conjunction with a special granulate, a firm and resilient weld seam is created, which is not only highly temperature-resistant and waterproof as well as dishwasher safe, but can also be easily processed (painting, grinding, drilling and thread grinding).

This welding process is not suitable for absorbent materials. For PE, PP, Silkon and Teflon, special pre-treatment is necessary.

Plastic Welding Machine

The hot-air fan welding machine is specifically designed for the processing of thermoplastics and is used for assemblies or repairs that require precise temperature control and close tolerance welding.

It utilizes hot air combined with pressure to join materials together without any solvents or adhesives.

Samger 1500W 110V Hot Air Heating
Gun Plastic Handheld Hot Air Torch Welder Kit 

1600w Hot Air Torch Plastic
Welding Gun Welder Kit

The most important advantage of using a hot-air fan welding machine is that it can be used on different types of plastics while maintaining the same level of quality.

The adjustable temperatures make it easy to work with various thicknesses and varieties of plastic material.

You can also use common soldering iron for plastic welding although the heating and temperature control options are not there to make a perfect plastic weld.

Welding wire for welding plastic

It is important to use the correct type of welding wire when welding plastic, as this will ensure that a strong and clean weld is created. The thickness of the welding wire must be chosen carefully, as it should match the thickness of the weld joint being made.

When selecting welding wire for welding plastic, there are several factors to consider. Firstly, it is important to assess what type of base material is being used, as well as which type of plastic filler rod should be used in conjunction with this material.

Secondly, consideration must also be taken into account regarding the size and shape of the weld joint that needs to be joined – this will determine how thick your wire should be and whether or not you need multi-strand or single-strand wires.

When selecting a welding wire for plastics, it is important to consider factors such as temperature resistance, thermal conductivity and electrical properties.

Temperature resistance refers to how well the product withstands heat during the welding process; higher temperature-resistant wires are necessary when joining plastics at high temperatures.

It’s also important to select a product with good thermal conductivity; this ensures that heat energy easily flows between two pieces being joined together.

How do you weld plastic correctly?

Remember that plastic of similar types are only can be welded to each other. Dissimilar plastic welding is not possible.

E.g., you can weld PU to PU or polyethylene to polyethylene type and not vice versa.

This is due to the different physical and chemical characteristics of each plastic type. Different plastics have different chemical composition and melting temperature.

So, make sure you weld same type of plastic grade with each other to have a perfect and good quality weld joint.

How to Weld Plastic: Steps by step procedure

The process of plastic welding is relatively simple but requires some preparation and the right tools in order to ensure a successful weld.

Below are some steps for plastic welding that will help you get the most out of your welding:

Clean the Surface

Make sure surface is free from dirt, grease, oil and other contamination. Use soap and warm water to clean the surface before making a weld.

The oxide layer present on the plastic surface can affect the plastic welding quality. Therefore, make sure to clean before you weld.

Selection of Right Plastic Welding Rod

The selection of the right plastic welding rod is essential for ensuring a successful weld. Proper selection involves considering the type and grade of the plastic being welded, as well as the size and shape of the piece to be welded.

It is also important to consider environmental factors such as temperature, humidity, and air quality when selecting a welding rod.

100 pieces Plastic Welding Rod

40PCS Plastic welding rods
ABS/PP/PVC/PE welder rods for
plastic welder

Plastic welding rods are generally made from nylon, polyethylene, or polypropylene materials in various sizes and colors.

The size of the welding rod should correspond with the thickness of the material being welded; thicker materials require thicker rods.

Different colors can indicate different properties or grades within certain types of plastics- for example, white or gray may indicate higher density than black or yellow rods.

Researching these properties before making a purchase is essential for finding an appropriate product for any given application.

Welding the Plastic

The first step when welding plastic is to preheat your welding gun for 2-5 minutes. This helps ensure that the temperature stays consistent throughout the entire process.

Once preheated, you will need to adjust the temperature of your gun according to what type of material you are working with: 275 °C (525 °F) for PVC; 260 °C (505 °F) for polythene; and 300 °C (570 °F) for PU.

Always remember that different materials require different temperatures in order for successful welds.

Temperature range for Plastic Welding

In hot (air) processes for plastic welding, devices can reach different temperature ranges. The maximum temperature is around 600 °C, but many devices reach significantly lower temperatures.

The temperature of welding machines should be as accurate and infinitely variable as possible or at least a larger number of adjustable temperature levels should be available. Ideally, temperature and power can be preselected directly.

Accessories for Plastic Welding

For plastic welding, not only the device alone is required, but also different attachments for different repair work as well as various additionally required tools.

For complete sets, there is sometimes a significant price advantage. In most cases, however, welding rods must be purchased separately to match the respective plastic. Individual required attachments can also be purchased separately for most devices.

What temperatures are used for welding?

The highest temperatures are required for welding ABS and polystyrene plastic grades, generally in the range of 270 °C to 310 °C.

For other plastic types such as PE or PP a lower temperature of around 220 °C to 280 °C are used, for PVC plastic a temperature of 250 °C to 280 °C is used.

Welding temperatures for different plastics grades

  1. ABS (acrylonitrile butadiene styrene): 270°C and +310°C
  2. PS (polystyrene): 270°C (520°F) to 310°C (590°F).
  3. PE (polyethylene): 220°C (428°F) to 280°C (535°F).
  4. PP (polypropylene): 230° (446°F) and +280°C (535°F).
  5. PVC (polyvinyl chloride): 250°C (482°F) and +280°C (535°F).


How does plastic welding work?

Plastics with thermoplastic properties can be melted and joined together in a liquid state (usually under pressure). As soon as the plastics have hardened again, a permanently stable connection is created because both joining partners are fused together. So, this works in a very similar way to metal welding.

What temperatures are used for plastic welding?

The highest temperatures are required for welding ABS and polystyrene, using temperatures from 270 °C to 310 °C. For other plastics (e.g. PE or PP) only around 220 °C to 280 °C are used, for PVC temperatures of 250 °C to 280 °C are used.

Is it possible to weld different plastics together?

No, this is not possible. Due to the different properties and ingredients, the plastics would not bond with each other, even if both joining partners are meltable. A stable connection would not be achieved because both materials would not mix sufficiently

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