Mould Making

Watusi has many years experience in all types of moulding using fibreglass, silicone, waste plaster, vacuum-forming, for a wide range of production materials such as perspects/acrylic plastic, urethane, polyester, epoxy resisn and food for many types of industries.

Fibreglass moulding is a process in which fibreglass reinforced resin is formed into useful shapes.  Fibreglass resin is preferred process because you can make any shape and it is tough, durable,lightweight and lovely to paint on.

Two-part silicone systems are used to create rubber molds used to cast resins, foams, rubber, and low-temperature alloys. A silicone mould generally requires little or no mould-release or surface preparation, as most materials do not adhere to silicone.

Watusi provides moulding products and facilities at a reasonable cost. Many of our customers return because of our flexibility to adapt to their requirements without significant cost increases normally associated with bespoke manufacture.

Fibreglass moulding is ideally suited to low volume production runs or one-off items.

Contact us to discuss your moulding requirements.


The fiberglass mould making process

The fiberglass mould process begins with an object known as the plug or buck. Watusi can sculpt or fabicate the original plug/buck. This is an exact representation of the object to be made. The plug can be made from a variety of different materials.

After the plug has been formed, it is sprayed with a mould release agent, if needed. The release agent will allow the mould to be separated from the plug once it is finished. The mold release agent is a special wax, and/or PVA (Polyvinyl alcohol). 

Once the plug has its release agent applied, gelcoat is applied with a roller, brush or specially-designed spray gun. The gelcoat is pigmented resin, and gives the mold surface a harder, more durable finish.

Once the gelcoat is applied, layers of fiberglass and resin are laid-up onto the surface. The fiberglass used will typically be identical to that which will be used in the final product.

In the laying-up process, a layer of fiberglass mat is applied, and resin is applied over it. A special roller is then used to remove air bubbles. Air bubbles, if left in the curing resin, would significantly reduce the strength of the finished mold. The fiberglass spray lay-up process is also used to produce molds, and can provide good filling of corners and cavities where a glass mat or weave may prove to be too stiff.

Once the final layers of fiberglass are applied to the mold, the resin is allowed to set up and cure. Wedges are then driven between the plug and the mold in order to separate the two.

There are downsides to using fiberglass moulds – they are not flexible, i.e., no undercuts. That’s when multiple parts to a mould need to be made, making it more complicated! Hence using silicone rubber moulds gives you greater flexibility for complex moulding. 

Watusi is expert at advising you on the best process, depending on what you are trying to mould. Contact our master model maker, Justin Robson, to discuss your project and get an estimate of manufacture costs and timelines on telephone 0404 878 389 or


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