How Seldén Carbon Masts are made

Seldeen Carbon Spar © Seldén Mast

I took a look around the Seldén Mast factory with Richard Thoroughgood from Seldén to find out a bit more about how the carbon tow reels become the masts that we use when out sailing.

Richard explains: "Everything we produce in the carbon range starts from a 'wind file', which controls reels of pre-impregnated carbon tow. Whether it is a product we have made thousands of - J70s, Musto Skiffs, ILCA composite top masts - or a yacht product (usually custom) we can alter the file to control the bend characteristics of the spar, the weight, or even cross-mix with glass fibre to keep costs under control. Everything is designed in house with our technical team."

Watching the winding process is mesmeric, as the machine travels up and down the rotating mandrel, creating each mast to a specific, pre-programmed design. We get to see the finished product out on the water, especially when a clear finish is applied, but watching the process of their construction happening is fascinating.

Richard took me through the many different processes of a carbon spar construction: "We have a rotating aluminium former (mandrel) which is first coated in a releasing agent, and we lay E-glass patches anywhere that we want to cut, drill, or fix to later.

"The machine initially lays a 90 degree wrap of carbon tow for integrity, and then uses the wind file to lay further layers at different angles as the designers specify; this could be 45 degrees, 12 degrees etc. Everything is laid under tension, in the same way reinforced concrete is made, so that when it is baked it is as rigid as we need it to be."

The masts are then cured in the autoclave, which is an exceptionally long pressurised oven, and then removed from the mandrel using a hydraulic puller to extract the aluminium tube from the inside of the carbon spar. This is the moment they find out whether the releasing agent has worked!

Then the spar is ready for finishing, with either the natural carbon look or painted a colour. All are treated with an ultraviolet inhibitor to prevent UV damage. Carbon head boxes, boom brackets and vang brackets are then moulded on by hand.

The team at Seldén can produce some pretty exotic shapes, including custom projects and and specialist reefing booms.

Richard talked me through the 'Y' boom construction: "The boom is the structural part, wound in the usual way, and then the wings (which enable a good flake when you lower the sail) are non-structural.

"The wings are made of foam and glass, built up and shaped, and then everything is faired in and beautifully sprayed in the booth."

Find out more at www.seldenmast.com/products/masts/#bm_carbonmasts