How to Structurally Repair Cracks in a Car Bumper

More than 5.5 million car crashes occur in the United States each year for a total estimated economic cost of $230.6 billion. A 6 mph Hyundai Elantra front bumper fender-bender adds $4,954 to that total. On average low speed crashes cost $6,364 in replacement parts and repairs, and a low speed crash in a luxury car, like an Infiniti G35, can more than double those costs.

The ability to repair parts instead of replacing them can greatly reduce the cost of repairs. While some parts are better replaced, items like bumpers can easily be structurally and cosmetically repaired with the right tools.

How to Structurally Repair Cracks in Automobile Bumpers

What You’ll Need:

• Hot Air Gun
• Steel Wire Mesh
• Metal Roller
• Auto-body’s Dolly or other heat sink
• Bondo or other 2-part epoxy filler
• Sandpaper
• Matching Paint

The Steps

1. Cut wire mesh so that at least 1 inch extends beyond each side of the crack. The wire mesh restores the structural integrity of the area.

2. Use a heat gun to heat the inside of the bumper around the area of the crack until the plastic is pliable. The temperature and heating time required are dependent on the plastic composition of the bumper.

3. Use a metal roller to roll the wire mesh into the inside of the bumper to join the two sides of the crack together. Apply counter-pressure to the outside of the bumper with an Auto-body’s Dolly or other heat sink.

4. Reapply heat and pressure until the wire mesh is integrated into the plastic.

5. For cosmetic finishing, use a two-part epoxy filler on the outside of the bumper to smooth the crack. Then sand, prep, and paint the bumper.

Request more information on bumper repair kits from Malcom Company.

Reduce Drying Time

From Leister News Letter: Process Heat (Jan)

Reducing the time required to remove moisture from many different applications can be extremely challenging. In an effort to reduce this time, Leister has developed an Infrared (IR) Heater that is capable of incorporating heated or ambient blown air through an IR Heater to improve drying conditions.

Leister’s IR Radiation Heater combines heat absorption and convection at the same time. By combining both technologies (hot air and IR) drying times can be greatly reduced as can be seen in the below graph where roughly .28 more ounces of moisture were removed from a non-woven fabric by combining both technologies versus using IR alone.

The infrared spectrum of Leister’s IR Radiation heater is in the mid-level at approximately 2.5 – 6µm which is absorbed by most materials. The response time is also less than 15 seconds with a power rating of 1500W.

View more technical information regarding Leister’s IR Radiation heater at Automation Technology Expo West (www.ATXWest.com) Booth #4574.

About Leister

Leister is a long-standing Swiss company that prides itself on lasting customer satisfaction. With the highest product quality, continuous innovation, profound staff experience and outstanding services our customers should expect no less.
No matter what you heat, for more than 60 years Leister has been providing the heighest quality hot air tools. With six decades of experience under our belt, Leister is the world leader in the areas of plastic welding and hot air devices. Additionally, beginning in 1995 Leister expanded into developing powerful, trendsetting laser and microsystems technologies.
To ensure you can always rely on the renowned Leister quality, we develop and manufacture all our products, parts and accessories in Switzerland.

Heat: A Visual Tour of What’s Hot or Not in the Universe

The universe is hot… How do Leister heat guns stack up? Well, somewhere between the melting point of aluminum and the temp. of typical lava flows. I suppose hot enough to melt, shrink, and form plastics.

Plastic Welding School

Plastic welding is a highly desirable skill.  According to Larry Rowald, instructor at the Plastic Welding School, there are four general principles of plastic welding.

1st Principle - Like Welds Only With Like Plastic

Basically only identical thermoplastics can be welded together. Whether you have HDPE, Polypro, PVDF, Acrylic, or PVC, only like welds with like. Therefore, the first step in the process of plastic welding is to identify the material.

2nd Principle –  Correct Temperature

In order for plastic to be welded the material must first be heated up so that it becomes plasticized (doughy). Think about welding as defrosting a steak before marinating it and throwing it on the grill. Your homemade teriyaki and sesame seed sauce will be wasted on a cold slab just as a plastic that is too cold will never weld.

3rd Principle – Even Pressure

Pressure is equally as important as temperature. A weld joins two separate plastic entities into one with no seam line. In order to achieve that coalescence, even pressure must be applied. Pressure is typically applied with welding rod when welding joints, or a pressure roller when joining tarps or overlapping seams.

4th Principle – Constant Welding Speed

Go too fast and you get no coeslescence. Too slow and the plastics begin to degrade. The key is to find the correct welding speed for the tool and the plastic, which can only be optimized through developing what the Plastic Welding School’s Lead Facilitator, Larry Rowald, describes as the “welder’s touch”.

Applied Learning

Most of us were able to quickly pick up the “welder’s touch” in class. The three days of the class were spent perfecting the “touch” using the full fleet of welding tools from Leister on every style of welding imaginable, and discussing the physics surrounding the realm of welding.

To find out more about the plastic welding school, fill out our contact us form and include “Plastic Welding School” in the application notes or go to www.plasticweldingschool.org.