Custom Prepreg Racing Bike Frame

Thomas Waldner is a retired industrial designer. He started working back in ’78 as a 18 year old and started early on working in the model shop. The last 20 years of his career, he was in several senior design management roles at various tech firms. CAD and 3D printing skills were learned on the job. CNC and his composite skills were self-taught.

He started making surfboards with his older brother when he was a teenager, then followed this up, 10 years ago, by learning to work with hand layup carbon fibre - making kite, hydrofoil and wing boards. When Thomas retired 3 years ago, he decided to try making carbon bike frames in pre-preg following being inspired by Easy Composites' videos on making Forged carbon parts using 3D printed moulds, Carbon Fibre Bike Frame and making Carbon Fibre tubes.

The wheel dropouts were the most difficult parts to make. The chain stays used EB700 model board CNC'd to make the moulds. It turned out well and he rode that bike for 6000km. The next year he decided to mould all the tubes, except one. For the third Frame, he made a more advanced frame with integrated handlebar and hidden brake hoses. At this point, the frames were still ”tube to tube” construction. However with Frame 4, he decided to make EB700 moulds of all they key parts, then bond the parts together. This method meant it was possible to make the design much more organic. He also made a rather radical handlebar and stem integration within this forth design.

A jig was made to support the pieces during curing in his home made oven. The Moulds were made from the EB700 Tooling board, then sealed with S120. The actual frame is made of XC130 210g twill cloth and multiple layers of the XC130 150g UD prepreg. The dropouts were made using the forged carbon process using the CT12 Chopped Tow. A variety of vacuum bagging materials were used to bag and cure the various moulds. Machining was done on an Ooznest Workbee and 3d Printing on a Creality K1 Max plus a variety of other machine tools and equipment.