In the second feature of our Fettlers series that looks at some of the most incredible home-made bikes, the focus turns to carbon and specifically the process used by one bike builder to make his own carbon fibre-based mountain bike frames and components.Adrian Smith uses 3D Printing technology to manufacture the moulds for his CAD-based designs, and then uses carbon fibre fabric to lay over the moulds and produce the final part.The costs of 3D Printers have come down in recent years and are no longer the preserve of big businesses. In Smith's case, he built his own 3D Printer up from scratch at relatively low cost. Since then he hasn't looked back and has built several inexpensive XC and Downhill bikes under his Carbon Wasp brand name in his home garage in Leeds.Don't forget that you can keep up to date with all things bike on redbull.com/bike.