Casting a Clear Sculpture Using Hapco Materials, Equipment, and Expertise – Part 2

Part 2: Casting the Unicorn

Hapsil Mold with Ultraclear Unicorn

In part 1 of this how-to guide, we showed you how we created the silicone mold using

Hapsil™ 360. In part 2, we will go through the steps and materials needed to cast a water clear part out of Ultraclear™ 480N-40, using Hapco’s X-80 Molding Chamber and X-Vac™ Chamber.

Measuring the Ultraclear

Ultraclear™ 480N-40 is weighed out and poured into plastic containers. The B side is then added to the A side container.

Mixing Ultraclear

The Ultraclear™ 480N-40 is mixed thoroughly for 2-3 minutes. It is a good idea to periodically scrape the sides and bottom of the container. Pouring into a second container and re-mixing is also recommended.

X-Vac Vacuum Chamber

The mixed resin is placed into the X-Vac™ Chamber and degassed, removing air and moisture from the mixture.

The mold is placed upright in the X-Vac™ Chamber and the Ultraclear™ is slowly poured into the mold, leaving about 1/2” from the top of the mold.

Degassing Mold

The vacuum is turned on and the mold is watched carefully to avoid any material rising over the edge of the mold. One hand is kept on the valve to avoid any mishaps.

Pressure Cast Ultraclear Resin

The mold box is placed on the X-80 Molding Chamber shelf and topped off with Ultraclear™.

Close Pressure Pot Door

Close the chamber door and tighten the clamps in a crisscross pattern. Slowly open the valve until the tank reaches the desired pressure. We recommend between 70-80 PSI.

Remove the Mold

The following day, the chamber is depressurized. Once relieved of pressure, the C clamps are loosened and the mold is removed.

Remove Mold from Frame

The wooden frame is disassembled and the silicone mold is removed.

Remove Cast Part from Mold

The silicone mold is laid flat on the bench and the two halves are carefully pulled apart.


The flash and vents are trimmed off. There will be a slight visible line where the parting line was. This can be buffed and polished after the piece is post cured.

Post Cure Casting

The piece is placed in an oven at 80˚C for 8 hours to speed up the cure time and to strengthen it.

If you have any questions regarding this tutorial, or any of Hapco’s products or equipment, please feel free to call us toll free at: (877) 729-4272