What kind of glue is used to bond car bumpers?
2 Answers
Structural adhesive is used for bonding car bumpers, as detailed below: 1. The bumper is a safety device that absorbs and mitigates external impacts, protecting the front and rear of the vehicle body. 2. The outer panel and cushioning material are made of plastic, while the crossbeam is formed by stamping cold-rolled thin plates (approximately 1.5 mm thick) into U-shaped channels. 3. The outer panel and cushioning material are attached to the crossbeam, which is connected to the frame longitudinal beams with screws, allowing for easy removal. Methods for repairing bumper scratches are as follows: 1. Apply toothpaste to shallow scratches and wipe with a soft cloth in a counterclockwise motion. 2. Spray car paint scratch repair agent onto the scratches and wipe with a towel. 3. Use a touch-up pen to spray and fill the damaged area along the direction of the scratch. Once dry, apply fine wax.
I've repaired quite a few bumpers. These plastic parts usually require modified cyanoacrylate adhesive or two-component epoxy adhesive. Most car bumpers are made of PP (polypropylene) plastic, which has an exceptionally smooth surface that's difficult to bond - ordinary glue simply won't hold. Repair shops most commonly use PP-specific adhesive with toughening agents. Before application, you need to wipe off the surface wax layer with a primer, and mix a plastic adhesion promoter into the glue for better bonding. Last time I used 3M's DP8005 structural adhesive to repair a cracked bumper - it sets in just ten minutes under pressure and becomes stronger than the original plastic after 24 hours. Remember never to use regular superglue (502), as its brittleness can corrode the plastic and leave white marks.
