Jonas explained the basic construction at the 1997 European championships but has kindly added extra details through e-mails Each boomerang is individually made from a number of materials and processes, including moulding them so each one is identical and perfectly tuned as soon as it is made. Construction is from a composite of materials as shown below The longitudinal carbon fibres forms the outer layer with the aramid underneath it. In the elbow section the longitudinal carbon fibre layers run straight all the way to the edge of the boomerang and are overlapping at the elbow. The top plan is an arbitrary section, the lower one is closer to the real thing. Aramid fibres are brownish yellow by nature, but when manufactured by DuPont they colour it bright yellow and use the trade name Kevlar.
Carbon fibre is pitch black.
You may remember one of my MTAs being yellow with the black underneath. This was one of my lighter experiment booms. I think I started making wooden MTAs around 1988 or 1989. The first composite MTA was thrown in 1989 and in late 1990 or early 1991 I made the first boom from my present mould. I'll have to check on the later date to be certain.