Back in October I attended a Composites 101 class at Nova Labs. Taught by NL member Bo (an aerospace engineer), the start of class was a short lecture about composites in general, including a show and tell of various bits and pieces he’s collected over the years (a piece of a prototype tail-rotor shaft for a large helicopter was particularly cool).
The second and third parts of class were hands-on where we got to practice working with carbon fiber sheet and epoxy resin. Everyone in class got to make a carbon fiber money clip, and then the class built a wine bottle holder where we utilized honeycomb in addition to many more sheets of carbon. That project also gave us a chance to prepare for vacuum bagging a part.
So, how did we make the money clip?
- Prior to class, Bo cut several parts from lite plywood and pink foam insulation on the laser cutter. Everyone got a set of these and some nuts and bolts to hold it all together.
- Stack the parts up and fasten them with the hardware.
- Prepare the two sheets of carbon fiber, mainly by securing the edge with masking tape, and trimming it down to be just wide enough to hold the edges together.
- A sheet of acetate (very smooth, thin, plastic sheet) is put on the table, and the mixed resin is spread in a thin layer on the acetate.
- The first sheet of carbon fiber is laid onto the resin, and then more resin is added on top of it fully wetting out the carbon fiber.
- Add the second sheet on top of the first, and add more resin to wet it out.
- Lay the second sheet of acetate on top of your resin-infused carbon, making a goopy sandwich.
- From here, we bent the whole thing into the jig, and clamped the assembly together to allow it to cure.
- Due to the time constraints of the class, we didn’t get to finish the parts that day. Bo came in a few days later and cut them down on a bandsaw, and sanded the edges.
While the surface finish of mine wasn’t perfect (I had several little bubbles) I think it came out pretty well for a first attempt.