Less comprehensive but no less important, small damage repair – or repairs to confined areas that do not require extensive metalworking or welding – requires the same amount of care and use of best practices as large damage repairs in your collision repair. These 3M standard operating procedures (SOPs) for Small Damage Repair deliver the knowledge you need to complete successful small damage repair using filler and glaze. Our step-by-step guide includes the techniques and products for preparing small areas for primer and paint, starting at pre-cleaning and proceeding through sanding, mixing and application of materials and final inspection.
Washing the entire vehicle prior to disassembly – even for small damage repair – can make all subsequent cleaning steps faster and easier and help you identify any hidden damage. It’s a simple step that can be done efficiently in any shop.
3M recommends pre-washing the vehicle exterior with soap and water followed by a VOC compliant surface cleaner on all repair areas, full panels, jambs and adjacent panels. Use a dedicated microfiber detail cloth for each step. 3M also recommends power washing the vehicle undercarriage at and near the areas of repair.
Sand the repair area using a dual action (DA) sander with a grade 80 abrasive disc. DA sand to remove all paint at the area of repair.
Be sure to extend the sanded area 2 to 4 inches beyond the damage. This is very important for small area vehicle repairs, because applying filler or glaze beyond the base coat edge can result in repair mapping and costly comebacks. Blow off the entire vehicle with clean, dry compressed air. Include recesses, door jambs, wheel well areas and anywhere else that dust and particulates can settle. Re-clean the entire area with VOC compliant surface cleaner.
Mix and apply filler per the manufacturer’s recommendation. To control filler/hardener mix ratio and virtually eliminate pinholes, use the 3M™ Dynamic Mixing System (DMS). DMS also lets you apply filler directly to the spreader without a mixing board.
Apply a tight coat of body filler to the repair area. This will ensure the substrate is fully wetted-out. Then build up the area with thin wet-on-wet filler coats. Make sure to keep the body filler within the primer feather-edge area to prevent repair mapping. Cure the body filler 15 to 20 minutes at 75°F/24°C.
Using a hand block, shape sand the body filler with an 80 grade abrasive. After the initial sand, apply 3M™ Dry Guide Coat to highlight remaining imperfections such as scratches and pinholes in the repair area.
Block sand the filler again, this time using a 150 grade abrasive. Apply another layer of dry guide coat and repeat if necessary. Next, DA feather-edge the repair area with a DA sander and a 180 grade abrasive disc. If glaze is not required for this small damage repair job, you can skip to the final step.
Blow off the repair area with clean, dry compressed air, completely removing sanding dust from the surface. Mix and apply polyester glaze per manufacturer’s recommendation. To control the glaze/hardener mix ratio and virtually eliminate pinholes, use the 3M™ Dynamic Mixing System.
Once the glaze is mixed, apply a tight coat first to ensure the substrate is fully wetted-out. Then build up the area with thin wet-on-wet coats. Make sure to keep the glaze within the primer feather-edge area to prevent repair mapping. Cure the glaze for 15 to 20 minutes at 75°F/24°C.
Using a hand block, sand the polyester glaze with a 180 grade abrasive. Apply 3M™ Dry Guide Coat to highlight imperfections. Re-apply glaze and/or dry guide coat and block sand as necessary. This step will leave the damaged area level and ready for primer application.
Blow off the entire repair area with clean, dry compressed air. Feather-edge the area surrounding the filler and glaze using a 180 grade abrasive. Be sure to remove remaining straight-line scratches from the repair area and abrade the outer perimeter for primer. Inspect the repair area and the surrounding panel for quality.