GRP Laminating Process Explained
GRP (Glass Reinforced Plastic) production involves a series of processes and in this article we are going to focus on the GRP laminating process.
GRP is the most cost effective and flexible solution for industries developing products that require strength, versatility, and long-term performance. Every GRP product undertakes a GRP laminating process; a hands-on, carefully controlled technique that transforms raw materials into durable, lightweight structures.
At AllScope Projects, the laminating process involves 5 key stages:
- Mould preparation
- GP Resin and catalyst mix
- Glass fibre sheet placement
- Resin application
- Roll out and consolidation
The GRP Laminating Process
Stage 1: Mould Preparation
Every GRP component begins with a mould (also referred to as a tool or mould tool) that defines the shape of the final product.
The mould is thoroughly cleaned to remove dust and potential contaminants and, for parts that require a high-quality finish, a gelcoat is applied to create a smooth and weather-resistant surface.
Stage 2: GP Resin and Catalyst Mix
A mixture of GP resin and catalyst is created and rolled onto the mould to commence the curing and lamination process. Catalyst is a chemical that reacts with the GP resin and hardens (curing) the resin to the required strength. This application is time and temperature sensitive.
- High temperatures speed up the curing process and can cause the laminate to cure too quickly which can leal to surface imperfections and shrinkage. In warm conditions the catalyst to GP resin ratio is reduced.
- Lower temperatures can slow the reaction which can lead to incomplete curing or weak and tacky bonding between the layers. In colder temperatures the ratio may increase.
The ratio is detailed in technical data sheets.
Stage 3: Glass Fibre Sheet Placement
Once the gelcoat has cured, glass fibre matting is laid into the mould and forms the reinforcement of the laminate. It is important all corners are covered for when we are ready to extract it.
Stage 4: Resin Application
We then continue to spread the GP resin and catalyst mix with a brush to cover the glass fibre matting in a process referred to as ‘wet out’. The mix covers the complete area to ensure strength and consistency.
Stage 5: Roll Out or Consolidation
In another vital role, we use hard rollers to press out any air bubbles and fully compact the laminate. This ensures a true consolidation and improves the durability. We also use a dry roller to ensure any excess resin is removed and prevent it attacking the gel.
Stage 3 and stage 4 are then repeated, dependent on the required strength.
As you can see, the GRP laminating process is a time sensitive and skilled role. Rushing the process, lack of attention to detail, the mix ratio and room temperatures are all important elements a laminator has to consider to avoid poor application and ultimately lead to defects and structural failure.
GRP Laminators at AllScope Projects
All our GRP laminators at AllScope Projects are trained on specific skill sets and understand how their application affects other stages of GRP manufacture and the final product.
As a Made In Britain GRP manufacturer we are proud of our training process and on-going personal development of our team.
Read more about GRP manufacturing process including GRP Mould Tools here.
To find out more about GRP manufacture or how we can develop your next GRP project, get in touch by clicking here or call us on 01282 446330