To start, you will want to find a bumper that is worth repairing. It should be straight enough to suit you. If the bumper has more than a few chips, cracks, or other damages, (which most do) the bumper needs to be stripped before you even think about the paint. There are many ways to strip your bumper. Sand blasting in one of the best ways. If you are unable to, you can also bead blast it. Depending on which way you want to sand blast it. Using a DA with 80 grit you will be able to remove 95% of the paint.You will want to make sure not to distort the contours or sand into the Endura material. To remove the other 5% use DA with 180 grit. The corners and inside edges are usually done by hand. The hand sanding is very time consuming but a MUST if you want a quality job. Attention to detail in this area will insure satisfactory results. Always stay away from chemicals. The chemicals can cause damage to the Endura material, causing paint problems later.Now that it is stripped, you will want to check again for chips and cracks. You will want to fill these and shape them to match the contour. Your filler MUST be flexible or you’re wasting your time. If there are severe cracks and gouges, they have to be prepped so that the filler material will bond. Deep cracks should be V cut with a cut off wheel or a file so filler will adhere. Be sure to press filler into repair area firmly. Several coats may be required to achieve a uniform appearance. All other imperfections should be filled at this time. Once filled has cured, sand with 80 grit to desired contour. Then do a final sand with a 320-360 grit sand paper. The entire bumper MUST be sanded smooth with 320 – 360 grit before application of flexible primer surfacer.Now that you are satisfied with you work, you’re ready to start priming. Blow and tack entire bumper until clean, free of dust and debris. You will need to apply 2-3 medium coats of primer surfacer. Once cured, apply a guide coat of contrasting color to help you detect scratches, imperfections, and low areas. Sand with 400 grit wet in a cross hatch motion. Do this until you are able to recognize your high and low areas. Repeat this process until the surface is straight and imperfections are gone. All areas need to be coated before color coat can be applied. The final preparation is to sand it with 600 grit wet until uniform appearance is achieved. The surface should be smooth and free of imperfections.
Before applying color coat, blow and tack until clean. If you are using a single stage add a flex agent. If you are using a base/clear system, add flex agent to the clear. You MUST use a flex agent in your top coat or you can be assured that it will crack. Once it is cured, color sand with 1500 grit wet. Buff and polish to your desired luster.

Tips

~ When applying filler, position the repair area in an horizontal position so that the filler will not sag or run off, rather it will sink in and lie flat.

~ On your first 400 wet sand, stop sanding when you have sanded through the primer and can see the endura. Apply more coats of primer surfacer to the low areas you have detected. Repeat this until the entire surface is sanded and there is no sanded through areas. Be sure to use a flat block.

~ After your final 600 sand, let bumper sit in sunlight.This will allow solvents to be evaporated. The longer, the better. This is also a good idea to do after you have color sanded with the 1500 grit wet.