Building your own custom bumper is an exciting proposition. If you have the right tools and skills, you can greatly enhance the appearance and functionality of your vehicle. At the same time, a poorly planned or poorly executed custom bumper fabrication job is a waste of time and materials. Take care to plan out the whole project before you begin cutting metal. Use as much standard equipment as possible as a basis for your modifications. If you still have it, also use the original bumper as a guide for the length, width, and fastener location of the new bumper.
Tip #1 - Decide on the Type of Bumper
Decide what type of customer bumper you are going to fabricate based on your vehicle’s original installed equipment. Fiberglass bumpers are suitable for passenger vehicles, and heavy stainless steel bumpers are designed for light trucks. Either type of bumper requires a completely different method of fabrication. Each type also offers its own unique costs and advantages. Fiberglass bumpers are lightweight, cheap, and easy to make. Truck bumpers can be enhanced with a trailer hitch, step guards, or additional lighting.
Tip #2 - Use Manufacturer’s Parts Where Possible
Before you start deciding which parts of the new bumper to fabricate, check your manufacturer’s parts catalog. Use the original mounting brackets, wiring guides, and other parts as far as possible into the new design. This will save you time and energy later. Also try to save the original fasteners when removing the old bumper. In some models, the original fasteners are connected together to make it easier to tighten them. They do not require a second wrench to hold the nut against the bolt.
Tip #3 - Build Model
If you are building a fiberglass bumper, you will need to construct a mold out of foam blocks or cardboard. This technique can also be useful when building a metal bumper. Sketch out a cardboard template to check the placement of the trailer hitch or license plate lights. To avoid drilling new holes into the undercarriage of the vehicle, try to use the original mounting holes in the new design. Hold the template against the truck to see how it lines up.
Tip #4 - Build Bumper
Once you have built a fiberglass mold, you need to treat it with polyester primer, molding wax, and aerosol gelcoat. This will keep the polyester resin from sticking to the mold. Lay several sheets of fiberglass into the mold, bind them together with resin, and allow them to dry. The resin produces harsh fumes so work in a well-ventilated area. Creating a metal bumper requires more tools and a larger workshop. Simple designs involve several lengths of pipe bolted to the frame. If you have the talent, you can cut and bend sheet metal to replicate a more traditional bumper design.
Tip #5 - Prevent Rust
Work with high quality corrosion-resistant materials where possible. The space between the bumper and the frame can trap dirt, which holds moisture. This causes rust. Treat the inside of the new bumper with a spray of protective undercoat.