Glass-reinforced plastic (GRP) goes through a long and complicated process before it’s finally transformed into the GRP enclosures and cabinets that we’re so familiar with. One of the most desirable properties of GRP is its incredible strength and it’s the complex manufacturing process that gives it this unique property.
Manufacturing the fibreglass
To make glass fibres that are suitable for GRP, materials such as silica sand, clay, limestone and other minerals are gradually melted in a furnace until they are liquefied. This liquid is then pushed through bushings, creating tiny little strands of the filament which are then coated with a special chemical solution.
Once this process is complete, the individual strands are then bundled together to produce what is called a roving. The diameter of each strand and number of strands in each bundle determine the weight of the roving.
The rovings are either used in the composite application or are used to make chopped strand mats, which are the basis for many GRP products we use today. Different weaves of fibreglass can be manufactured for a range of different practical applications. The pattern determines the weight and strength of GRP, so depending on your needs a different type of strand mat will be used.
Making the GRP product
Once enough of these chopped strand mats have been made, they can then be used in moulds to create a range of products. Moulds are first treated with a special chemical mix which consists of resin, a hardener, a catalyst and pigment to ensure nothing sticks it. Once this has dried and cured, the first strand mat layer is fitted to the mould.
This process is then continued, with a layer of resin and a catalyst added after each new strand mat. Like before, it is then left to cure before another is placed on top. It’s this process that gives GRP its signature strength and the more layers that are added to the mould, the stronger the end product will be.
Creating GRP is a time-consuming process, simply due to the curing time in between layers but the end result is well worth it. GRP can then be sanded and painted, and used to make enclosures, housings, covers and a number of other useful products.
Visit GRP manufacturers www.kingsleyplastics.co.uk for more information on GRP products.