The flange on this Camaro bumper broke during a really minor collision. These flanges are fairly common on bumper covers, so, while this repair example is on a Camaro bumper cover, the techniques used will be the same on other bumper covers as well.
The first step in any quality repair is to clean the repair area. Use Super Prep Plastic Cleaner to clean. Spray on a heavy wet coat in a small area, let it sit for a few seconds to dissolve any contamination, then wipe in one direction with a clean paper towel, exposing a clean surface with every wipe.
Hold the flange to the side and sand away any paint that compromise the quality of the weld.
Use aluminum body tape to temporarily hold the flange in place. Aluminum body tape is very stiff and it can withstand the heat from the welding process.
Use the R02-03-03-NT polypropylene strip along
with the Nitrogen welder and run a bead along the crack line. Aim the flow of air at the intersection
of the rod and the plastic that you are welding. Be sure to melt both the rod AND the existing plastic.
After laying down some plastic, melt away the excess rod with the side of the welding tip.
The edges of the polypropylene strips tend to curl up on the edges. Use your airless plastic welder to melt down the edges.
Allow the weld to cool and remove the aluminum body tape. Grind away some of the existing plastic so that the flange will not be too thick when the new material is added.
Use the R02-04-03-NT polypropylene strip for the weld. Aim the flow of air at the intersection of the rod and the plastic that you are welding. Be sure to melt both the rod AND the existing plastic. After laying down some plastic, melt away the excess rod with the side of the welding tip.
Complete the weld along the entire crack line.
As you can see, this is a quality repair that saves having to buy a new bumper cover