Designed for versatility, low or high-production volumes, basic or complex shapes, and small or large sizes for projects requiring nominal capital investment.

The most versatile of all Fiber Reinforced Plastic (FRP) and composite molding processes, the Open Mold manufacturing process can be performed in a number of ways, including: hand lay-up, spray-up, and as part of a robotic spray-up application. Due to its versatility and low cost of tooling, Open Mold laminating effectively supports all levels of volume (less than 5,000/year), size, and component complexity. Goldshield has effectively utilized this process to produce components for multiple sectors of the transportation, recreation, environmental, industrial, medical, and agricultural markets.

Choose the open mold laminating process when your project requires:

  • Complex components
  • Versatility
  • “A-side” finishing
  • Low tooling costs
  • Prototype development
  • Program volumes less than 5,000-parts annually

Open Mold Laminating Processes

As the name implies, open mold laminating of Fiber Reinforced Plastics is achieved utilizing a single “open” top or bottom semi-rigid concave or convex mold. The desired “finished side” of the part dictates the orientation of the mold. In starting the manufacturing process, the mold is cleaned and prepped with a release agent. If a cosmetic surface finish is required, the mold surface is covered with a gel coat and allowed time to cure. The laminate structure (typically fiberglass) is “loaded” in the mold, combined with a thermoset catalyzed resin, and formed to the shape of the mold. At this stage, the molding process utilized to complete the part varies based on part dynamics and specifications. Those molding processes of FRP include the following:

Hand Lay-Up

In the hand lay-up process, the laminate structure, commonly a single continuous strand glass mat, a woven glass mat or an advanced composite mat is manually “hand-laid” in the mold. The catalyzed thermoset resin is introduced, and the materials are formed to fit the mold surface using a “roll-out” process, as well as a number of specialized laminating tools. Additional layers of reinforced mat can be added to key structural points to enhance rigidity and performance. The Hand lay-up process is most effective when molding complex surfaces, and is commonly used in the transportation, recreation, medical, and agricultural markets.


The most common method of Open Mold laminating, the spray-up process utilizes a customized spray “chop” gun that cuts or chops continuous strand glass (aka gun roving), and simultaneously mixes with catalyzed thermoset resin. The combined materials are manually sprayed to customer required thickness throughout the entire mold, then hand-rolled and formed with specialized tools. Due to the random orientation of the chopped fiber, the part is easily formed and provides outstanding structural integrity. The spray-up laminating process supports higher volume part programs, and is commonly used in the transportation, marine, recreation, and agricultural markets.

Robotic Spray-Up

Goldshield, with the support of key transportation partners, has led the industry in the high-volume method of Open Mold Robotic Spray-up Lamination. With multiple robotic spray-up rooms, Goldshield can support component programs in excess of 5,000-parts annually. Additionally, Robotic spray-up laminating systems reduce manufacturing variability, improve thickness control, and enhance structural integrity. Only a select few open-mold composite manufacturers have invested the capital, human, and financial to support robotics. Goldshield is a leader in this open mold laminating process. As noted above, Robotic Spray-up laminating is most effective in support of high-volume large parts, and is commonly used in the transportation industry.



From the employees behind the scenes, to the high-quality manufacturing processes we put in place, and the value-added services we provide to make your components a reality, Goldshield is committed to perfecting the way molded fiberglass manufacturing is done.




To begin work on your molded fiberglass project, visit our Contact Us page to send us a message. We’re standing by to deliver you with accurate, reliable, and repeatable FRP parts.