This is how I made the seatpost.
The problem with the original seatpost was the hefty weight and the proprietary shape. The shape is a mix between elliptical and diamond shaped.
However, the seattube is a perfect elliptical shape.
The original seatpost does not fit well in the seattube.
So I made a number of test pieces to replicate the inside shape of the seattube.
Once I had the basic shape I contracted it with the thickness of the wall of the carbon tube I was planning on using and printed a mandrel in ABS-plastic.
I roll wrapped 3K twill weave and UD pre-preg carbon fiber around the mandrel.
I cured the seatpost in a home made oven I made from a fruit drier, an old PC case and sound insulation. At full blast at 250W it kept a constant 82C over 5 hours.
For hardware I got some Schmolke parts for a 31,6mm seatpost and test fitted on a mock-up of the seatpost.
I cut the holes for the cradle and pin using a rotary tool and a guide block I printed and clamped around the seatpost.
And this was the result.