What is glass fibre-reinforced plastic?
GRP is a composite material made of glass fibres and a composite matrix. This composite transforms GRP into a very special material with different physical and mechanical properties depending on the composition and manufacturing process. Depending on the application, GRP can therefore be modified accordingly to best meet the requirements. In our article "Glass fibre-reinforced plastic (GRP) - a definition", we have summarised all the important information about GRP for you. Common application areas for GRP are, for example, the bus, caravan and commercial vehicle industries or the construction industry.
What is aluminium?
Aluminium is a chemical element (Al) and is a metal, specifically a light metal. It is the most common metal on earth and has a silvery white colour. The raw material is the ore bauxite, which is extracted by open-cast mining. Bauxite is first converted into aluminium oxide, also known as alumina, by a chemical process. The aluminium oxide is converted into aluminium by electrolysis. Ultimately, the desired shape of the metal is obtained through processes such as rolling, forging, extrusion or bending. Well-known products made of aluminium include aluminium foil, cables, cans or even components for vehicles.
Comparison between GRP and aluminium
Whether for windows, mobile homes or in the commercial vehicle industry: Opinions differ with regard to the question of whether aluminium or plastic is the better choice. Both materials have their advantages and disadvantages and, depending on the application, a disadvantage can also become an advantage. For example, conductivity: Aluminium is a very good electrical conductor and is therefore popular in electrical engineering, for example as conductor material in microchips. GRP, on the other hand, is not conductive.
On the contrary: GRP even has insulating properties and is therefore often used along railway lines, for example, to protect workers or pedestrians from traction current. It therefore depends entirely on the application whether electrical conductivity is an advantage or disadvantage.
In an exact comparison, the materials differ in different aspects:
If you compare the properties of glass-fibre reinforced plastic and aluminium, you can see that GRP offers advantages over aluminium in many ways. GRP is not only extremely lightweight, but also flexible. Aluminium is also relatively light and flexible, but there is always a risk of the material kinking and subsequently becoming dented. Glass fibre-reinforced plastic provides optimum insulation. GRP not only provides excellent thermal insulation, as it has significantly lower thermal conductivity than aluminium, but sound is also very well insulated by GRP. This is particularly advantageous for motor homes or driver's cabins in commercial vehicles. GRP reduces the noise level produced in hail or rainy conditions, so nothing will spoil your peaceful journey. GRP also scores highly with regards to cleanability. In our article "Which material is easy to clean?"
Which material provides greater protection against external influences?
Aluminium and plastic are used in a wide range of industries. However, most industries have one thing in common: They are not protected against external influences. Sunlight, rain and hail are just a few factors that can impair the materials. GRP or aluminium - which material is better in this case? How do the two materials perform he
1. Corrosion resistance
If a substance is destroyed over time by the effects of other substances in its vicinity, this is referred to as corrosion. The consequences of corrosion are not just visual on the surface of the material, in the worst case, the functioning of a component can also be impaired. To test the corrosion resistance of a material, most materials undergo a salt spray test. During the test, the materials are placed in climatic chamber and are continuously wetted with a sodium chloride solution. This speeds up the build up of corrosion and it quickly becomes apparent how corrosion-resistant the materials are.
2. Resistance to weathering
If we consider resistance to sunlight or hail, both materials have different advantages. Aluminium is UV-resistant and has a shiny surface that is not faded by sunlight as quickly and does not yellow as a result of weather conditions, which can occur with GRP. However, if the GRP surface is sealed with a Gelcoat, it is also extremely resistant to UV and weathering. In addition, GRP's material surface is more resistant to hail or stone chips, resulting in fewer dents in the surface. With regard to a vehicle roof made of GRP, this can also result in cheaper insurance rates, for example .
GRP and aluminium are largely equally resistant to scratches, but in an exact comparison, scratches on GRP are less visible than on aluminium. Again, the secret is to combine GRP with a high-quality Gelcoat. The plastic is chemically bonded to this Gelcoat layer during the manufacturing process, making the composite very robust. In addition, the Gelcoat layer provides greater thickness than conventional painting. These two differences reduce the risk of scratches penetrating the entire Gelcoat. And even if it happens, it's not nearly as bad, because: Unlike an additional colour paint, as is the case with aluminium, GRP and Gelcoat can be produced in a solid colour, making scratches less visible.
Subsequent painting, such as on aluminium, can cause the layer to flake off over time, which is why aluminium top coats often have to be repainted due to scratches, flaking or corrosion. Surface repairs can be made on both materials by overpainting, but GRP is less susceptible to scratches and saves money. Subsequent costs can quickly become very expensive, which is why the motto is: Carefully rethink material selection and thus save unnecessary costs.