Molded Steering Wheel Grips

Creating the Mold

After finishing the clay molding project, the next step was to create a silicone mold of my grips. I made a one part mold for each of the four grips by building foam core walls around five sides and spraying with mold release. After mixing parts A and B of the silicone, I put it into a pressure chamber to get rid of all the bubbles.

For batches where I was unable to use the pressure chamber, I just poured silicone in from high above the mold to ensure that large bubbles would be popped before getting to the part. When the final molds came out, it seemed to not matter whether or not I used the pressure chamber.

With the mold release, it was very easy to remove the foam core from the silicone. There was a little bit of flashing from where silicone seeped under the clay, but that was very easy to remove using an X-Acto knife.

Cast #1

For my first casting attempt, I covered my mold with an aluminum plate with a hole in it. The problems I encountered with this were that the resin did not cure correctly and that the part was stuck to the plate. The aluminum likely sank away too much of the heat during curing, causing it to not cure correctly. I also didn't use mold release on the aluminum, which would have helped the part come off more easily.

Cast #2

For my second try, I just poured resin straight into the mold without covering it. This resulted in the casted handles having round bottoms instead of flat, and they wouldn't sit flush on the plate.

Cast #3

For my final cast, I returned to the plate from cast #1 but instead made it out of clear acrylic and also applied mold release. The clear window also allowed me to see any bubbles that needed to be cleared out. This time the resin did cure correctly. I also sanded the handles a bit to get them smoother.