Plastic welding is the ability to take two pieces of plastic and weld them together. This is a type of weld that will be done on children's toys, lawn furniture, automobile parts and other types of plastic equipment that you may use everyday or commercially. This type of welding is used to join thermoplastics when they are heated and under pressure. Generally the pieces are fused together with filler material, but some instances do not require filler material. Plastic often has a shorter lifespan than most types of products because there are so many things that can go into how it is maintained. Elements from nature like cold weather, UV rays from the son or chemical contamination can create damage with plastic. Plastic can also receive damage if it is hit hard like in a car bumper or other hard surface, but the purchase of the new parts can be cost prohibitive; this is when it may be a good idea to repair it instead. There are different types of plastic so it is important to know which one you are working with in order to make sure that the proper welding material is used. It is a good idea to understand the difference between thermoplastics and thermosets because thermosets cannot be welded. The type of plastic that needs repair will require different welding rods and if you use the wrong rod for the plastic you need to repair, there will be no bond. Materials like Polyolefines have a lower surface energy so this means they cannot usually be repaired with an adhesive or other types of glue. There are a special group of polyolefine adhesives that can do this job. When you are making repairs on plastic there are usually two types that you will come up against -- you will either have to repair a crack or a broken part. If you find a crack, it means that there is some type of stress affecting the inside of the material you are using. This means that you will have to repair the crack and make sure it doesn't continue through the piece. There are several types of plastic welding. A few of them are: ? Hot gas welding uses a welding gun that has electric heating elements within in it that produce a heat of hot gas. ? Hot plate welding uses a hot plate between the two surfaces that are being joined. Ultrasonic welding uses a high frequency acoustic vibration to weld the pieces together. These are placed under high pressure and then exposed to the vibrations until the weld is completed. ? Spin welding where friction is used to weld two cylindrical parts as these parts are rotated. At a certain time the rotation stops and the weld is completed. ? Vibration welding takes to pieces of plastic and exposes them to a frequency called an amplitude. The two pieces are under pressure which causes a friction that generates heat. All of these types of welding work on plastic and they are geared towards working with a variety of polymers. Go to Welder World to get your free ebook on Welding at Welding. Welder World also has Welder Forum, Learn Welding Blog and other information on Welding Information and daily news. You can Find Welding World at .