The process for making carbon fibre bicycle parts can be complicated. When you add in the one-off custom element, this process not only needs to be the concept and prototype stage, but also the final production. This is the process from start to finish for creating the tailbox and lunchbox for my BMC TMR01 road bike. This covers the methods and process from initial shape definition and design, mold making, carbon layup and finishing. All work was done at home with limited tools and shows that with a bit of creativity you can make it work.
The first step is determine the final silhouette.
After working out the panels in 3d with paper, the shape gets transferred to a wood block to create the plug that will eventually get built up with carbon fibre fabric.
Using the fence for guidance, the wood block gets cut to shape to form the mold.
In this case, the mold has multiple compound angles and tapers. This photo is shaping the vertical plane to narrow at the top.
The mold also gets tapered from front to back on a table saw.
Once happy with the shape, it gets sanded and painted to seal the wood.
Although a wet layup is not optimal, it works just fine for a one off/non structural part like this.
Once the carbon is applied and ready for cure, it gets tightly wrapped with a peel ply fabric that firmly holds the carbon in place while it hardens.
After cure, a bit of a trim and sanding, you get something that resembles the final part.
Once you are happy with the shape, the bottom gets bonded in place. This box will be adhered to the frame using double sided tape.
The lid gets cut out of the box and support rails are added.
Because this part has been sanded heavily, I applied a final clear coat to seal the carbon.
All ready for finishing.
Satin black paint with satin clear to match the frame.
The steps for the tailbox are mostly the same, creating the mold and preparing the carbon for lay-up.
This shape is mush simpler and I was able to use simple compression to set the wet carbonic place.
Three parts fresh off the molds, box, lid and spine.
The weave of the lid was lined up to insure the same look as the box (however I decided to paint it in the end and it’s not visible).
A simple band-saw trim to get the 2 parts to meet perfectly.
The spine gets bonded to the box. As with the lunchbox, this one will get adhered to the frame with extra strong tape.
Support rails bonded in to help keep the lid and box aligned.
Final test fit with all components in place.
Final finish to match the lunchbox, sating black with satin clear.