Pickup Truck Flareside Plastic Side Panel Repair

Some pickup trucks have urethane side panels on the pickup bed. They are usually called "Flareside" (Flare Side) or "Stepside" (Step Side). These panels are very expensive to replace. If you can find a donor panel from another pickup truck from, say, a salvage yard, then you can save a lot of money by repairing the panel. It's easy to do, too.

Polyvance was formed in 1981 as Urethane Supply Company to address the needs of bumper recyclers and to supply products to repair urethane bumper covers. Around that time, many people did not think urethane bumpers could be repaired. We proved they can be repaired.

Polyurethane is a thermoset plastic, meaning that it is NOT meltable. The solid is formed by reacting two liquid components which crosslink 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. This will not provide a fusion weld. The urethane welding rod is used more like a hot melt glue.

You can use our Mini-Weld Model 7 or the integrated airless welder that is part of our nitrogen plastic welding systems to perform the repair. These two options are recommended because you need to be able to control the temperature of the welder.

This article can help you determine if your plastic part is thermoset polyurethane or a thermoplastic.

Always wear proper safety gear while working!

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Products Used:

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.

• Aluminum Body Tape (several options available)
• 6122 Heavy Duty Round Cutting Burr
• 6029 Bigfoot Welding Tip
• 2000 Flex Filler (several options available)
• Waterborne Primer Surfacer (several options available)
• Polyurethane Welding Rod and an Airless Plastic Welder(choose a method below):
• Polyurethane Welding Rod with the airless plastic welding side of a nitrogen plastic welder. Our current nitrogen plastic welders include the 6027HT Standard Welding Tip.
• 5700HT Mini-Weld Model 7 (230V kit is also available). The 5700HT kit includes a 15 foot starter roll of polyurethane welding rod and the 6027HT Standard Welding Tip.
• Note: Make sure you are using either the 6027HT Standard Welding Tip or the 6029 Bigfoot Welding Tip when using the round polyurethane welding rods.

Video Notes:

• This type of repair can be done with the Mini-Weld Model 7 or the airless side of a nitrogen plastic welder.
• English Closed Captions have been provided for this video. Click on the CC button to turn them on or off.
• The length of this video is in no way representative of the actual time required to perform a complete repair and therefore should not be used for estimating purposes.

English Transcript:

In this video, we will show you how to repair a thermoset polyurethane part using the airless plastic welder. This is a urethane Chevy bedside panel with a chunk missing. It also has a crack and some smaller areas missing. We are going to take a section from a scrap pickup bed and splice it into the missing area.

First, clamp in the donor section behind the missing section. Once it is clamped into position, use a marker to trace out the edges of the missing area onto the donor section. Cut the patch out of the donor section using a jig saw. Trim the edges as needed to get the best fit possible with the patch panel.

Use aluminum tape to tape the patch panel into position. V-groove about halfway into the urethane with a die grinder. We are using a carbide burr from Polyvance in the air die grinder.

The airless welder is used to weld urethane. When welding urethane, it is very important to set the temperature of the welder properly. If it is too hot, the rod will boil and turn watery. Set the welder at the "PUR" setting so that the rod comes out the bottom of the welder tip clear and melted, but not smoking and bubbling. Hold the welder slightly off of the surface to avoid overheating the base material.

Because the fender is made of thermoset urethane, it is not meltable. So when we repair urethane with the airless plastic welder, we are not actually "welding" the plastic; instead, the repair is more like a braze or a hot melt glue. The urethane welding rod has very good adhesion to the plastic and makes a very strong repair.

Fill the v-groove with melted urethane welding rod. Go slowly and press down on the welding rod to force the rod down into the pores of the plastic. If you are doing a long bead like this, you may need to increase the temperature of the heating element to compensate. Maintain a temperature that melts the welding rod completely, but not to the point that the rod turns to a watery liquid.

Once the weld cools, peel the tape from the other side. V-groove the backside and prepare to weld it. Melt the welding rod into the v-groove again on the backside. Notice that we are reinforcing the edges by grinding a v-groove along the edge and welding there, too. Apply more welding rod on the backside as needed to reinforce.

Once the weld is completely cool, grind the weld slightly flush with a 50 grit Roloc disc. Use 80 grit in a DA to feather back the v-groove and paint to prepare the plastic for filler.

Mix the 2000 Flex Filler epoxy in a one-to-one ratio. Mix completely until it turns a uniform gray color. Wipe the Flex Filler over the welded area. Do not use polyester glazes over urethane, as they do not have the necessary flexibility.

Sand the Flex Filler with 80 grit in a DA sander. Do final profiling with a sanding block. Once you have achieved the final shape, sand all over with 180 grit paper and feather the paint back and blow the dust free. Finish the repair by spraying one of Polyvance's flexible waterborne primer-surfacers.