The intricacies of the shape of the figures required the Entech Creative team to lay the parts up by hand. More challenging was this client’s industry-leading fire-retardancy requirements, which necessitated a significant amount of suspended solids in the resin mix. To work with this material, Entech Creative upgraded its equipment to higher horse-power pumps that would accommodate the AOC K133 Firepel polyresin along with the additional suspended solids. “Great care was used in the mixing and handling of these resins,” Moore says. “Batches were mixed in limited quantities and a vibratory platform was used to ensure the solids would remain suspended in the mixture.”
The lamination schedule started with gel coat, followed by a layer of chopped strand mat and a composite of chopped strand and woven mat material. Next, another layer of woven material was added for bulk. For interior part quality, Entech added two additional layers of chopped strand mat to complete the laminate schedule. Finally, the interior surface was sprayed with a gel coat finish.
Entech Creative was able to achieve a high rate of predictability on the weights of the parts, with values falling within five percent of expectations.
Entech embedded the internal armature – an aluminum ribbed structure – into the parts. This armature was attached to the external skin using plexus adhesive and mechanical fasteners. “While the thermal expansion of aluminum and FRP are not that far off, we created a gasketed joint between the mechanical fasteners and the FRP so the different materials could move independently,” Moore says.
To permanently join the individual body pieces to create a monolithic part, Entech used a full lamination schedule. First, the parts were mechanically fastened together to ensure correct position. Then, a 6 x ¼-inch channel was machined into the parts spanning the seam. Next, the laminate schedule was laid into the channel. Finally, a fiberglass putty mix was used to smooth the overall surface. To complete the FRP process the entire body surface was sanded as preparation for primer.
Afterward, the figures were mounted in their show position. Scenic artists hand painted the figures to match Pixar’s creative intent. After ample curing time, Entech applied an automotive clear coat to provide durability and UV protection.
Because of the scale of these unique parts, Entech Creative couldn’t afford to make any mistakes. When creating the initial shape of the parts, multiple quality control measures were taken to ensure the figures were dimensionally correct. Test coupons were created prior to any part lamination. These coupons were tested to ensure sufficient solid suspension and complete and proper catalyzation. “If it’s not catalyzed properly, it’s going to lead to all sorts of problems,” Moore says.
In the end, the firm’s diligence paid off. “We were actually able to deliver a little early on the job,” Moore says. “Everything went smoothly.”