Filament Winding technology

SILOTANK have introduced the first 3 Axis Filament Winding Technology in the UK and Ireland.

The process by which our fiberglass tanks are manufactured speaks volumes about their quality, integrity, safety and longevity.


Our tanks are made on steel moulds from the inside out. Steel moulds provide us with a firm and consistent surface upon which we apply materials to make our tanks. The rotation of the mandrel and the application of the materials are controlled by a computer. As the mandrel rotates, resin, glass are precisely metered onto the mandrel. The result is a closely controlled process and a very consistent tank wall composition and thickness.

After the tank wall is made, its thickness is precisely determined. An instrument that magnetically senses the metal mould surface through the fiberglass reinforced plastic laminate is used to accurately measure the thickness of the laminate at many points all over the surface of the tank wall. This method of thickness measurement with a metal mould is quick, easy and more exact than the ultrasonic methods used by other manufacturers.

Stronger tanks, inside and out:
The inside-out approach to building the tank wall has some other advantages as well. The first layer of materials forms the inside surface of the tank. Because of the smooth steel mould, the inside surface of the tank is very smooth and free of surface variations. The inside surface is not exposed to air as it cures, which eliminates the air inhibited surface cure problems sometimes associated with other methods. The result is a well-cured and very smooth tank interior surface.

By applying materials to the outside of the tank, we can easily add additional thickness, reinforcing ribs, filament winding glass in tension, glass woven roving, glass mat, or any other materials in specific locations on the tank wall. With this capability, we use the most efficient materials in the most efficient locations to meet the design requirements of the finished tank. Additional wall thickness is added exactly where it is needed. Ribs are applied in optimal locations, made in the most efficient shapes, and constructed of the most efficient reinforcing materials. If a different rib shape or height or location would be better, the form or the location of the rib can be changed. If the rib form shape was a part of the mandrel, these changes could not be made without changing the mandrel itself.

Our laminate has been thoroughly tested to meet the requirements of BS4994-1987. Additional long-term corrosion testing continues with our Research and Development Partners. This results in data that can be used to accurately predict the long-term properties needed for accurate tank designs.

Range of mould sizes: 1.0 metre, 1.7 metre, 3.0 metres, 3.5 metres, 4.0 metres and 4.5 metres