This video demonstrates a series of practical, time- and cost-saving techniques for producing a complex, one-off carbon fiber composite part. The project showcased is the creation of a super-stiff monocoque chassis for a jet-propelled RC car aiming for a world record.
The core methodology deviates from traditional composite manufacturing by directly CNC machining the molds from low-density PU model board, bypassing the expensive and time-consuming step of creating a pattern and a production mold. To make the porous board viable, it is sealed with an epoxy coating. The video details the choice of a room-temperature resin infusion process over pre-preg carbon fiber, a necessity due to the mold's temperature limitations. The intricate process of laying up dry carbon fiber and a Soric core into the split molds, setting up a complex envelope-bagged infusion, and the successful execution are shown in detail. The result is a high-performance, lightweight, and void-free chassis produced in just three days, highlighting the trade-offs of this rapid prototyping method, namely the limited mold lifespan and the need for post-processing to achieve a perfect surface finish.
Rapid Prototyping a Carbon Fiber RC Car Chassis
0:00 Project Goal: To build a complex, one-off carbon fiber chassis for a world-record attempt jet-propelled RC car on a tight budget and timescale.
1:49 Rapid Tooling Shortcut: Instead of machining a positive pattern to create a production mold, the negative mold is machined directly from low-density PU240 model board. This dramatically reduces CNC machining time from over a day to just a few hours.
4:51 Sealing the Low-Density Mold: The porous and delicate surface of the low-density board is sealed with XCR epoxy coating resin. This creates a hard, non-porous, and workable surface essential for the resin infusion process.
7:20 Why Resin Infusion? Resin infusion is chosen as the ideal process. Pre-preg is ruled out because its high curing temperature would destroy the low-cost molds, and a simple hand layup would not provide the structural performance and quality required for this high-performance part.
11:13 Laying Up Reinforcement: Dry reinforcement materials, including 210g carbon fiber twill and Lantor Soric core material, are carefully cut and positioned in the molds using spray adhesive (Fusion Fix) to hold them in place.
15:50 Assembling the Split Mold: The two halves of the main chassis mold are bolted together. A solid, 3mm thick floor is created using five plies of heavy 650g carbon fiber to bridge the seam and provide strength for mounting hardware.
19:06 Complex Infusion Setup: The setup for the infusion is detailed, using a combined peel ply/mesh (ML3), MTI hose to regulate resin flow and draw a vacuum, and a central resin feed spiral. The entire mold assembly is then "envelope bagged."
24:58 Infusion with High-Temp Resin: The parts are infused with EL160, a high-temperature epoxy resin, chosen to withstand heat from the jet engine. The infusion takes approximately 20 minutes for the main chassis.
27:35 Successful Demolding & Results: The resulting parts are incredibly stiff, lightweight, and perfectly replicate the mold's detail with no voids. The rapid tooling method created minor surface texture, a known compromise for speed and cost savings. The molds survived and could likely be used for 2-3 more parts.
29:37 Final Finishing: The parts are trimmed, post-cured at a high temperature, and then flatted to remove high spots. They are finished with a high-build clear coat, which is applied in multiple stages to achieve a perfectly flat, high-gloss surface.
30:50 Project Conclusion: The combination of tooling shortcuts and resin infusion proved highly effective, allowing the creation of a high-performance chassis in just three days of hands-on work with under £1,000 in material costs—a fraction of the cost and time of conventional methods.