We help people repair plastic
Vehicle bumper covers are damaged every day. A tear that extends to an edge of a bumper cover is one of the most common types of damage. Polyvance’s airless plastic welder can be used to repair this kind of damage. In this video, we describe our repair process on a polypropylene bumper cover.
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Note: This is a list of the Polyvance products that can be used to make this repair. This list does not include sanders, grinders, or other common tools you will need. If you have any questions, please don't hesitate to call technical support at 800-633-3047.
Vehicle bumper covers are damaged every day. A tear that extends to an edge of a bumper cover is one of the most common types of damage. Polyvance's airless plastic welder can be used to repair this kind of damage. In this video, we will describe our repair process on a polypropylene bumper cover.
First, we cleaned the damaged area with plastic cleaner to remove the contaminants from the surface. We aligned the tear and applied aluminum tape to the cosmetic side. Aluminum tape is used to secure the tear and prevent melted welding rod from pushing through.
Next, we prepared the backside for welding. Using a die grinder, we exposed the raw plastic around the tear, about half an inch on all sides. Because we will embed stainless-steel wire mesh into the edge for extra support, we used our die grinder to expose the raw plastic at the edge, about an inch on both sides of the tear. Then we cut our stainless-steel mesh to fit the area.
Next, we began our airless plastic weld. This bumper cover was made of polypropylene, so we selected Polyvance's polypropylene welding rod in the round zero-one profile to match. To make a proper fusion weld, the filler rod must be the same type of plastic as the base material. It's also essential that both the filler rod and the base material are melted and mixed together.
First, we used the tip of the welder to melt a small indentation in the plastic along the tear, and then we pushed the displaced plastic back into the indentation. We then fed the welding rod through the tube in the tip and onto the melted plastic. Once we applied enough filler rod, we used the welder tip to mix the rod and base material together and smooth the weld. The key to this type of repair is to only work in small sections. Don't try to weld too large of an area at one time, because the plastics will cool down before you have time to thoroughly mix them. We continued to weld all the way down the tear using this method.
To give extra strength to the repair, we embedded our stainless-steel wire mesh into the edge of the bumper cover and applied more filler rod. First, we placed our mesh down onto the plastic and laid the welder tip over it, melting the plastic beneath the mesh. When the plastic was melted, we pushed the mesh into it with a metal tool. We did this a little at a time until the mesh was fully embedded in the plastic. The surface of the plastic had begun to cool down, so we used the welder tip to re-melt the plastic while we applied the filler rod on top. After we applied enough filler rod, we mixed the base material and filler rod together and smoothed the weld. At this point, the backside weld was complete.
Once the backside weld was cool, we removed the aluminum tape from the cosmetic side and applied it over the weld on the backside. We cleaned the cosmetic side with plastic cleaner to remove any adhesive residue. We sanded the repair area with eighty grit sandpaper to expose the raw plastic. We welded the cosmetic side the same way we welded the backside.
We melted an indentation into the plastic along the tear, pushed the melted plastic back into in the indentation, fed the welding rod through the welder tip, and pushed the filler rod onto the melted plastic. Once we applied enough filler rod, we mixed the welding rod and base material together and smoothed the weld. We worked in one-to-two-inch sections at a time until we finished welding the tear.
Once the plastic was cool, we removed the tape from the backside and sanded the weld down with 80 grit sandpaper. At this point, the welding was completely done, and the repair was incredibly strong.
With the welding complete, it was time to start the refinishing work. Our repair was a little low, so we needed to apply filler. We sanded the surrounding area with 80 grit sandpaper, followed by 180 grit sandpaper. We removed the dust from the area and applied two coats of adhesion promoter. Next, we applied Polyvance's Flex Filler 2 epoxy and allowed it to cure. We then sanded the filler with 80 grit sandpaper, followed by 180 grit sandpaper.
Next, we scuffed the paint around the repair area. We removed the dust and applied two coats of adhesion promoter. We applied our first coat of Polyvance's Black Jack waterborne primer and block sanded the primer with 320 grit sandpaper. After that, we applied spot putty where it was needed, and then block sanded the putty with 320 grit. We removed the dust and applied our next coat of primer. At this point, we were satisfied with the appearance, and ready to have the bumper cover painted.