Plastic repair GURUS since 1981
Bumper Repair with Plastic Welder
FiberFlex is Polyvance's "Universal" rod. FiberFlex is formulated with carbon and glass fibers for the strongest, fastest repairs. It is not a true fusion weld; instead, the FiberFlex is a hot-melt adhesive that is applied with an airless plastic welder. So, it is similar to a brazing process. It sticks great to polypropylene and TPO.
Do not attempt to weld the FiberFlex rods with the nitrogen plastic welder.
This video will demonstrate a bumper cover repair using an airless plastic welder and FiberFlex welding rods.
This article gives the basics on how to use Polyvance's FiberFlex universal welding rods.
Always wear proper safety gear while working!
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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.
Set up your welder by screwing in the flat welding tip. Adjust the temperature control of your welder to the R10 setting and allow time for the welder to reach operating temperature. You will need to select the FiberFlex rod for this repair.
Cut the stainless steel reinforcing mesh so that the mesh will span the crack about a half inch on each side of the crack. Use the welder to bury the mesh into the plastic. Let the heat from the welder soften the plastic before applying pressure. The stainless steel reinforcing mesh works like rebar in concrete to strengthen the repair. This method can be used on any thermoplastic, or meltable plastic. Melt down and flatten out any high spots and smooth the edges. Do not apply excessive pressure. Instead, let the heat from the welder do the work. FiberFlex does not stick well to glossy surfaces. Remove the gloss by sanding with 80 grit sandpaper. If the plastic is torn to the edge, you will need to bury the mesh into the edge as well. Melt the mesh into the plastic, then fold the mesh around the edge and melt the mesh into the backside. Again, do not apply excessive pressure; let the heat from the welder do the work. Once again, remove any gloss with 80 grit sandpaper.
Apply the FiberFlex by pre-melting one side of the rod. Flip the rod over so that the melted portion sticks to the plastic, then use the edge of the welder tip to cut off the melted part of the rod. Spread the FiberFlex into the v-groove. Do not attempt to melt the base material together with the rod, just melt the rod onto the plastic. Repairing with FiberFlex is similar to a brazing process. Cover the mesh on the backside with a layer of FiberFlex to strengthen the repair. The thicker the layer of FiberFlex, the stiffer the repair will be. Allow the FiberFlex to cool, then remove the tape from the opposite side.
Grind a rough, broad v-groove halfway through the plastic with 50 grit or coarser sandpaper. Be sure to grind at slow speed to avoid melting the plastic. Remove the paint surrounding the damage with a DA sander and 180 grit sandpaper. Apply FiberFlex in the same manner that it was applied to the other side. Remember, do not attempt to melt the base material together with the rod; just melt the rod onto the surface. Allow the FiberFlex to cool before sanding.
Sand the FiberFlex with 80 grit sandpaper to knock down the high spot. Then finish sanding with 180 grit sandpaper. Sand at slow speed with a new, sharp piece of sandpaper to avoid excessive friction heat buildup. You may need to apply additional FiberFlex to fill in any low spots. Finish sanding with 180 grit sandpaper and blow off the dust.