Nitrogen Plastic Welding - SkillsUSA Competition

Introduction

• Presenter: Kurt Lammon, Polyvance
• Focus: Nitrogen plastic welding for plastic repair in collision repair technology, SkillsUSA competition.

Safety Precautions

• Eye Protection: Wear safety glasses to protect against flying plastic shards.
• Hand Protection: Wear gloves.
• Avoid Burns: Do not touch the metal barrels of the nitrogen or airless plastic welders.

Task Overview

• Repair Objective: Fixing a 2-inch tear in a bumper's edge, high-stress area.
• Tools Needed:
  • Straight or angle die grinder with 50 grit Roloc
  • DA sander with 80 grit sandpaper
• Materials Supplied:
  • Plastic cleaning solution
  • Aluminum body tape
  • Plastic welding rods

Preparation

1. Surface Cleaning:
   • Use a plastic cleaning solution.
   • Apply a heavy, wet coat and wipe dry with a clean cloth, turning it for a clean surface.
2. Plastic Identification:
   • Identify plastic type; select appropriate welding rod (polypropylene blend for competition).

Welding Process

Backside Welding

• Grinding:
  • Grind backside to expose raw plastic.
  • Options: Grind flat or create a v-groove.
• Alignment:
  • Use aluminum body tape on the cosmetic surface to maintain alignment.
• Welding:
  • Preheat bumper and rod end.
  • Stick rod down, apply light pressure, ensure simultaneous melting of rod and bumper for fusion.
  • Allow cooling before proceeding.

Frontside Welding

• Preparation:
  • Remove aluminum tape.
  • Grind a deep v-groove into the plastic.
• Welding:
  • Use 1/8 inch round polypropylene rod for a narrow repair.
  • Melt filler rod and base material together, ensuring proper fusion.
  • Apply second pass if needed.
  • Smooth with hot airless welder.

Finalization

• Cooling:
  • Let weld cool to room temperature.
• Sanding:
  • Sand smooth with 80 grit in a DA sander.
• Integrity Check:
  • Flex part to check weld strength.
  • Ensure professional look and durability.

Conclusion

• A well-executed nitrogen plastic weld is strong and durable, capable of withstanding substantial force.