Fiberglass-Polypropylene (Experiment #1)

My kitchen smells like smoke.

Experiment #1:

Made plaster mold to form PP sheets into the shape of a small-scale car hood (1sq/ft). Sheets were premade on the heat press. Melting PP fabric directly into the mold is not viable. Fabric must first be combined with glass in a separate production step to make a part of uniform density suitable for being formed into a mold.

Sheet Properties:

Weight: 56g

PP Fabric: 6sq/ft

Chopped Glass Mat (1oz): 1sq/ft

Thickness 0.025”

PP composite material stuck to the rough surface of the plaster mold. This may have been caused by the glue within the fiberglass mat that was not broken down by the fabrication process. The PP-fiberglass composite may adhere to the mold surface less or not at all in the absence of standard glass mat adhesive.

The plaster mold contained a lot of moisture content after curing. A crack formed at the outside edge of the mold and stretched 60% of the way to the center upon initial warming at a temperature of around 250°F at the center and 100°F at the perimeter. This crack continued propagating throughout the mold’s drying process in the oven and split the mold into two pieces by the time the experiment was complete.

Due to insufficient heating equipment and the geometry of the mold, there was a significant temperature difference between the center of the mold and the perimeter. This posed a significant challenge in keeping the PP in a liquid state. A heat gun was used to soften and melt the three sheets of PP-fiberglass composite into the shape of the mold, one sheet at a time. The process took 15 minutes, and because the heat was not being applied uniformly, there were areas in the completed part where the sheets did not fully fuse into each other.

Watch the video below to see the whole process!