Plastic Identification… What Can Be Welded? What Can’t?

Plastic Identification… What Can Be Welded? What Can’t?


When fusion welding with a nitrogen plastic welder, you will have to identify the type of plastic you’re working with and select the right kind of welding rod. There are many types of plastics, but
only a few are used on auto parts. This section of the video will help you select the right kind of welding rod for the project you’re working on. About ninety-five percent of late model car
bumpers are molded from polypropylene blends. These are meltable thermoplastic materials. These are usually black or dark gray,
but sometimes they can be white. They will usually have a PP symbol
molded into the backside. These plastics are sometimes identified as TEO or TPO. They are always a blend of polypropylene,
synthetic rubber, and other fillers, and their proportions vary depending on the
resin manufacturer and the application. These PP blend plastics can be welded with
our polypropylene or TPO welding rods. Since this is the most common plastic, we have many varieties of rods to match different applications. Your welder comes with three different profiles
of natural polypropylene rod: round, narrow ribbon, and wide ribbon. You will also have a selection of black polypropylene
rod and also some gray TPO rod. Some bumpers are still made of polyurethane. This was a popular material years ago and
it’s still used on a few applications today. They’re usually yellow on the backside, but not always. You’ll see the ID symbol where it says PUR or RIM. Polyurethane is a thermoset plastic,
meaning that it is not meltable. The solid is formed by reacting two liquid
components, which cross-link in the mold. You will not be able to use the
nitrogen welder on this type of plastic. You can repair it with the airless plastic welder. Instructions for this type of repair are shown
in a later section of this instructional video. Most other plastics used on cars are
thermoplastics, or meltable plastics. In this case, plastic pellets are
melted and injected into the mold. The plastic then cools and re-solidifies. Thermoplastics can be welded with the nitrogen welder. Common types are polyethylene,
ABS, nylon, and polycarbonate. Polyethylene is often used on
overflow and washer bottles. Nylon is used on radiator tanks, core
supports, and other under-hood parts. Polycarbonate is used on body panels and bumpers. See the plastics ID chart that came in the
literature with your welder for more details. We’re going to focus in this
video on welding polypropylene, since this is the most common
kind of plastic you’ll be dealing with. Once you learn how to well polypropylene properly, you’ll be able to identify the other types
of plastics and weld with those as well.

About the Author: Michael Flood

16 Comments

  1. You guys are one of the best choices to ask the question I have . I have had an Idea for my recently finished roof rack floor . Instaed of adding a lot more weight than I would like using expanded sheet as a floor . I thought of welding together some thinker bread racks . . Making a plastic grated floor . Any tip's , advice, Or suggestions would be greatly appreciated and well recived . Thank You and God Bless .

  2. what kind of plastic do you think those water storage containers are their kind of white clear translucent color

  3. Which welding rod do I need for Kydex or Boltron? I have looked through your book only to not be sure which rod to get.

  4. How can I fix a big crack in my side by side ATV floor? A big rock hit the underneath and made a big crack going from bolt to bolt!! Please help I will try to fix myself.

  5. I am a plastic welder and have always used the appropriate ventilation but is there any need for a mask or resperator from breathing in what isnt clean air

  6. Im trying to repair an ac scnitzer BMW bumper but it has no stamp other than "made in germany" TPO and PP wont stick to it at all, any ideas what it could be made of?

  7. Music does not belong in instructional videos. This particular music with the look of this particular video was so bizarre it was actually funny. The music undermined the professional look of the video. Honestly couldn't stick with it. I was out at 44 seconds and that was on double speed with some short jumps forward.

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