Creating Chassis Molds

To make a Carbon Fiber Chassis, we created a negative model that acts as a female mold to apply the uncured carbon to. 

Finished mold Interior

The chassis is large enough that we split the plugs and corresponding molds into multiple pieces (Upper front, lower front, upper rear, lower rear).

Exterior of finished molds

 This allows us to redesign a single part of it without remaking all the molds. To make the molds, we first manufactured plugs. A plug is a model of the final design that we use to produce a mold. First, we laminated multiple pieces of foam together using resin and machine them down to the shape of the car. Then we sealed the foam using spray on sealant. This produces a smooth surface and fills in the gaps in the foam.

Upper Rear Sealed Plug. 

To make the mold, we first applied mold release to the surface of the plug, this stops the resin from bonding to the surface of the mold during curing. Then, we cut and lay up dry carbon over the surface of the plug. We then seal it in vacuum bagging using the correct peel ply and infusion mesh, and perform an infusion. 

Carbon on surface of plug

Peel ply, mesh, and vacuum bagging attached. 

Notice the tubes. One feeds resin into the carbon, and the other gets a vacuum attached to it pull the resin through the carbon. This produces a negative model of the car that can be heated to 350 F. multiple times without deforming or breaking down. 

Resin infusing into the carbon

Resulting mold from the infusion. The flange around the outside is used for attaching the different molds together. 

This mold was then sealed with the same paint as the plugs and hand sanded and polished. This produced a super smooth surface for the carbon to be pressed up to without bonding to during the cure cycle. After painting and sanding, the resulting 4 molds were bolted together.

Disclaimer: For simplicity, I have skipped a few steps in this process. Do not use this as instructions. Feel free to contact me with any questions.