Fiberglass Lifecast

We recently delved into the world of fiberglass. Because our lifecasts are so large, we wanted to cast them in a material lighter than the usual Ultracal 30. After reaching out to our local Reynolds Advanced Materials, we were turned on to some new products. Because we are going to use them to bake foam latex, they suggested their heat resistant resins,  ApoxAcoat HT and ApoxAmite HT.

Safety Notes:

  • Well ventilated room (we were in an open garage with vent fan)
  • Wear gloves
  • These materials generate heat and may melt certain containers
  • Dust mask required for sanding


The molds used were the full head lifecast of Courtney’s head and a helmet we sculpted on Courtney’s skull.

We made sure the molds were clean and free of debris. Mold release was then applied to the surface.

The first coat to be applied was the gel coat. The purpose of the gel coat is to capture the detail of the cast, for this we used ApoxAcoat HT from Smooth-On.  It is very important to properly mix both components thoroughly before measuring out your portions. First we mixed part A using large wooden paint stirrers, making sure to scrape the sides and bottom.

Part A and part B were then measured out using a digital scale.

Once weighed, the two parts were mixed together for 3 minutes.

Using disposable chip brushes, we started brushing in the gel coat.

The material has the consistency of peanut butter and sticks well to vertical surfaces. Our coat ended up being about 1/8″ thick.

The gel coat was then left to cure for 4 hours

The next step was to prepare the laminating resin.

For this we used the ApoxAmite HT. Again, we thoroughly mixed parts A and B. The resin was measured out on the digital scale and then mixed together.

At this point we took sections of fiberglass cloth, and using a chip brush, we saturated it with the resin. The resin coated cloth was then brushed into the mold on top of the gel coat, tamping out all the air bubbles.

We continued adding the fiberglass cloth until we had about 3 layers. At this point we needed to connect the two halves of the head lifecast.


To help strengthen the seam line we added CaboSil to the remaining resin.

This filler thickened the resin to more of a paste.

The paste was brushed around the seams and the two halves were joined together. Once reassembled, we took a chip brush attached to a paint stick and applied more paste to the seam.  The resin was then left to cure for 24 hours.

Note: We used an overlap method when creating our plaster jacket. This saved us time earlier but made things more difficult to line up during the fiber glass process. We would recommend making a jacket wall connected with bolts and wing nuts if you plan to assemble two fiber glass halves.

Once cured, the mold shell and silicone were removed.

Success! Because some of the resin seeped out around the seam line we had some flashing to remove.

Using a spindle sander and our trusty Dremel tool, we cleaned up the edges.

The final step is to heat cure the fiberglass.

We will be heat curing the casts in our foam latex oven. The longer the piece is baked, the higher temperature resistance it will have. Because we are using this for foam latex, we need it to be cured for at least 160 degrees.