Restoring Stonework Using the EZ‑Spray® System


PROJECT: Make molds to replace crumbling stonework at a university in Australia.
PROBLEM: Project deadline is quickly approaching.
ANSWER: Use Smooth-On's EZ-Spray® Jr. system and EZ-Spray® Silicone 35 rubber.

Adelaide University's Bonython Hall in South Australia was in need of renovation. As part of the project, two domes at the back of the building had to be replaced due to the deterioration of the stone work. It was decided that an eight-section mold of one of the domes would be created. This mold could then be used for the recasting, in glass reinforced concrete, for both domes.

Russell Brown from Rubber Impressions was contracted to make the molds. After seeing a demo of Smooth-On's EZ-Spray Jr. system, Brown decided to make the dome molds from EZ-Spray Silicone backed with a mother mold of fiberglass.

The domes consisted of eight segments, each 2.6m high and 1.1m wide at the base, which were shimmed and sealed with Smooth-On's Super Seal®. Each section took about 6 hours to spray. Following the application of EZ-Spray Silicone, each section was then given a smooth coat of Smooth-Sil® 930 thickened with Thi-Vex® to fill any holes or unevenness on the surface of the EZ-Spray Silicone. This also helped prevent any mechanical lock on of the fiberglass support jacket.

Brown estimated that had he used a brushable polyurethane rubber each individual panel would have taken three days to mold. The EZ-Spray Jr. system saved him more than two weeks time and thousands of dollars in labor costs.

Materials Used in this Tutorial

Step 1: Preparing Materials