Welding is often seen as a difficult and frustrating process to master, but this isn’t entirely true when you consider it from a heating standpoint. If you’re new to plastic welding, try the techniques discussed here so that you can make those mistakes in the least amount of time.
To measure heat levels for a perfect weld, you need to know how much heat a plastic welder can produce in a certain amount of time. The best way to measure this is by using an infrared thermometer or two temperature sensors. You’ll need these tools even if your welding machine has an onboard thermometer as most do.
Hotplate and Wire Method
If you don’t care about the accuracy very much, then simply use a hotplate and wire brush approach: remove the wire and set it up near your heat processing tools. Measure the temperature on one end of the wire and in between each pass. This is often easier than using infrared thermometers because they’re typically designed for industrial use.
Infrared Thermometer Method
If you want to be more precise, measure the temperature with an infrared thermometer during each pass of the weld. You’ll have to take care not to burn through the plastic or get your hands too close, however. Measure both sides of the weld; you’ll be surprised at how much they can vary. Pay special attention to any areas where the wire is held back from flowing freely; these areas tend to be much cooler. If you’re having trouble getting a good measurement, try switching from continuous (this is best for most purposes) to pulse mode for a few seconds and then back.
Trial and Error
Last but not least, use trial and error to determine how much heat your plastic welding torch can produce in a certain amount of time. It is best to start with a low temperature and work your way up slowly. A good idea is to set up the hotplate with a wire going through it and heat the metal that you’re testing by clamping or clamping only one side of the wire in the pipe or duct. This will help prevent damage to your materials.
The Welding Temperature Is Too High
You can tell when the welding temperature is too high. Here are the tell-tale signs to look out for:
- The material looks burnt or scorched
- Extrusion welding – it is too hot if you can probe more than .5mm into the surface of the preheated area
- Smoke is a clear sign that your materials are too hot
The Welding Temperature Is Too Low
The other side of the coin is when you’re trying to weld at a very low temperature. Here are the signs to look out for:
- The material looks grey, dull, and flaky
- Extrusion welding – you’ll see a dark area appear where the weld has finished melting
- If you can see a dark area but it’s not completely melted, then heat it a second time and then reweld.
Ultimately, if you produce a strong weld then you’re on the right path. However, if the weld easily breaks you probably need to increase the temperature of your tools.