GRP Moulding

GRP,(Glass Reinforced Plastic) Moulding is a process which enables the manufacture of specifically designed products from Glass reinforced plastic, better known as fibreglass; these moulded products can be manufactured for a wide range of industry applications, such as, Building, Construction, Leisure, Marine, Aerospace, Automotive, and much more.

GRP moulded products can be manufactured to meet most requirements and specifications, further-more these mouldings can be manufactured to any size, shape, and can match any BS or RAL colour required with either a gloss, matt , smooth or textured finish's, in some cases peripheral components can be incorporated into this process, such as threaded inserts which can be bonded into the product to provide a fixing solution, or metal work which can be incorporated into the moulding to provide a mount for internal components such as electronics ect, During this innovative process, additional reinforcements can be incorporated into specific areas which will be under load or receive additional stresses; this is done during the laminating process, when additional layers of reinforcement can be applied into the required areas, or sub mouldings can be bonded in, in short, fibreglass moulded components can be tailored to meet any requirement, but lets talk about the process that makes it all possible GRP Moulding.

GRP Moulding is a process that starts off with the manufacture of a pattern also known as a plug or buck, this is a model made from Polyurethane foam or MDF (Medium Density Fibreboard) or another material, this model will replicate the required product exactly, with regards to the dimensions and surface finish, once the pattern has be manufactured and prepared the mould can be manufactured from it, the mould can be male or female depending upon the design of the product.
The manufacture of the mould requires a certain amount of skill and understanding, its this experience that will enable the correct tooling materials to be chosen and employed during the mould construction, the mould may need to be more than one piece depending upon the design of the product (flash lines, undercuts, intricacy ect are all thing to give thought to) if the mould is to be more than one piece, then locators will be required on the flanges to ensure the mould section align.

Now the mould has been manufactured and allowed to cure, the pattern can be removed from the mould, the use of compressed air or wedges may be required to break the seal between these parts, once the pattern has been released, the mould can be prepared with several coats of mould release wax, remember before you run the mould a coat of PVA (Poly Vinyl Alcohol) release agent is also good practice and will help the first product to release from the mould with out the risk of sticking.

Now the mould is prepared and ready to go to work, its time to go GRP Moulding,

1. This starts with the mould being painted or sprayed with gel-coat of the desired colour; the polyester gel-coat is the coating that will provide the pre-coloured finish to the moulded component.

2. Once the gel-coat has cured, a layer of glass fibre can be applied to the back of the gel-coat, the layers of glass-fibre is then saturated with resin, the saturated glass-fibre is then rolled with a special roller, this is to remove any trapped air, and to consolidate the glass-fibres, more layers of glass-fibre can be applied until the required thickness is achieved, the laminate is then left to harden and cure.

3. Once the laminate has cured, the product can be released from the mould, the product is normally left in the mould for twenty four hours, this ensures that the product has no imperfections, like, print through from the glass-fibre, shrinkage in the gel-coat ect, but remember, if there are any defects like the one's just mentioned, these can all be rectified by a skilled operative.

Congratulations, you now have an understanding of GRP Moulding, a truly innovative process for manufacturing fibreglass components, and remember you probably see products every day made from GRP, but you didn't realise it, that was until now!