The Importance of Contact Moulded Fibreglass Manufacture
Industry Standard for Best Chemical Resistance
Fibreglass laminates made by contact moulding, also called hand lay-up, have the highest resin to glass ratios of 70:30 when compared to alternative manufacturing methods. As it is the resin that gives a fibreglass laminate its chemical resistance, this high ratio makes contact moulding the preferred fibreglass manufacturing process when the highest degree of chemical resistance is required. In contact moulding, the main laminate is reinforced mainly with non-continuous glass fibre, and this limits the spread of any chemicals within the laminate should it be exposed or damaged.
After 11 years in service at temperatures fluctuating from 20ºC to 95ºC within seconds, the interior surface of the fibreglass pipe made from contact moulding has crazed from thermal shock, but the pipe remains structurally sound. The high resin to glass ratio (70:30), the non-continuous reinforcing fibres, and the reinforced resin rich interior surface all contribute to the successful service.
After less than 5 years in similar service: By comparison, pipe made by the centifugally cast method uses sand filled resin to create thickness and stiffness, and has an unreinforced resin rich inner surface. Thermal shock resulted in the resin on the interior surface cracking and flaking, exposing the underlying structural sand filled laminate, consequently the pipe failed.