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Main Welding - Plastic Welding

Main Welding - plastics repair welding

Techspan's Tech Tips will help guide you in achieveing a good understanding of the Plastic Welding process.  Each month we will provide you with new tips and techniques on how to get your Plastic Repairs right first time. Today we are looking at "Main Welding".

Main Welding:
The "Main Welding" of plastics can be carried out using two welding techniques. 1. Pendulum Welding 2. Speed Welding Firstly, please ensure you have followed the previous steps in the Plastic Welding process - as outlined in our previous "Tech Tips" Plastics Identification & Surface Preparation.

Pendulum Welding:
The "Pendulum Welding" technique, can be used for short weld runs, or when access is difficult. Fit the standard nozzle (LE100303) on the welding tool. Set the required welding temperature on the welding tool using the guide provided. This is carried out using the red rotary dial on the end of all Techspan Plastic Welders.  Once up to temperature (from cold, this takes approx. 1.5 minutes), select the correct welding rod (see our previous Tech Tip covering "Plastics Indentification"). Cut the start of the welding rod to a point. This will help with the initial flow of the weld rod. A pendulum motion is used to evenly heat the parent material and the welding rod. Feed the welding rod into the welding area, while curving the tail of the weld rod away from the welding tool. This will help you control the rod feed during welding and will allow the operator to observe the material flow during welding. Welding should be carried out in one continuous run along the length of the area to be welded. Welding speed should be adjusted to the point where you observe a slight 'wash' at the sides of the welding rod.  Ensure that your pendulum motion is providing even heating of both the parent material and the welding rod throughout the weld run. When complete, allow the plastic component to cool completely before attempting to trim or clean up the welding area. This is important as the plastic will not be at full strength until completely cool. Triming & sanding can now be carried out if required. 

VIDEO: Pendulum Welding Technique

Speed Welding:
The "Speed Welding" technique should be used for long weld runs. The term "Speed Welding" gets its name from the fact that it is a relatively fast process compared to that of the "Pendulum Welding" technique. Fit the standard nozzle on the welding tool. Select the correct "Speed Welding" nozzle to suit the corresponding welding rod profiel - these are available to suit a range of welding rod profiles. In round profiles, Techspan can supply 3mm, 4mm or 5mm diameter. In Tape profiles, Techspan supply an 8mm x 2mm Speed Welding nozzle. And in Triangular profiles Techspan supply either a 5.7mm or 7mm Triangular Speed Welding Nozzle.  The Speed Welding nozzles are an easy push fit onto the standard nozzle. Once up to temperature, simply insert the welding rod into the Speed Welding nozzle and apply a downward pressure on the welding rod itself. Apply approx. 2.5 - 3 kgs of downward pressure, forcing the welding rod through the speed welding nozzle and into the weld area. The welding tool will only need to be supported, as the force on the welding rod will move the tool along the weld area with ease. The "Speed Welding" process is fast, and very easy to achieve. 


VIDEO: Speed Welding Technique

The next Tech Tip will cover "Plastic Welding Tools" and will help guide you in purchasing the correct equipment for the job. Check back here for the next Techspan Tech Tip, or subscribe to the news page via RSS

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By Tim Fastnedge - Techspan Group