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Nitrogen Plastic Welding:
Standard Operating Procedure
This SOP will walk you through the steps of a basic nitrogen plastic weld.
- Plastic Cleaner (1000 Super Prep or 1001-4 EcoPrep)
- Die Grinder with Carbide Cutting Burrs (6122 and 6125)
- Aluminum Tape (6485)
- Nitrogen Plastic Welder
- Plastic Welding Rod
- 90 degree angle grinder with coarse sandpaper
- Dual Action Sander
IMPORTANT: Before you begin any repair process, please remember your personal protection. Select protective eyewear, respirator, gloves, clothing, and hearing protection appropriate to the job and level of exposure.
Step 1: Identify the Plastic
Find the ID symbol molded into the part and select the matching welding rod. PP (polypropylene, aka TPO or TEO) is the most common type, but PE (polyethylene) and PC (polycarbonate) are also quite common.
Step 2: Align, Clean & Prep Backside
Work out any distortions with heat and pressure. Clean plastic, then grind a v-groove into the backside to match the width of the selected welding rod. Use aluminum tape on the frontside to hold damage in alignment as you weld on the backside.
Step 3: Weld Backside
Use the nitrogen plastic welder to weld the filler rod to the base material. Direct welder’s heat to melt both plastics at the same time, applying slight downward pressure on the rod to fuse them together.
Step 4: Prep Frontside
When backside weld cools, peel aluminum tape from the front. V-groove at least halfway into the plastic with a die grinder, about the same width as the selected welding rod.
Step 5: Weld Frontside
Again use the nitrogen plastic welder to melt the base material and the welding rod together, applying a slight downward pressure on the rod. Apply multiple passes of rod if needed to fill v-groove completely.
Step 6: Sand, Fill, and Finish
When weld is completely cool, sand with 80 grit in a DA sander to profile. Apply a skim coat of two-part filler as needed to finish the repair and prepare for primer.