Aesthetically, wood is more pleasing to the touch and to the eye, but functionally, Delrin performs at least as well - and it s practically maintenance free. Also. because the material is non-porous, Delrin drones must be swabbed out more frequently than wooden ones, as water tends to bead up and roll down into the reeds more quickly. The pores in a wooden instrument break up the skin tension of the water that condenses in its bores, thus slowing this process. The sound does seem to be affected by how much pipes have been played, and how consistently in tune they have been played over the years. Given two identical instruments, with one having been well played for years and the other just stored for the same time, chances are the former instrument would have a superior tone.
Wood moves over time, with changes in temperature and humidity.
This is because the cells within the wood fibers accept or shed off water molecules to come into equilibrium with their environment. This movement is more pronounced tangential to the growth rings of the tree than it is parallel to them. A round hole bored in a piece of wood becomes oval over time. Further, as the grain in any given piece of wood isn t perfectly straight, you end up with a randomly twisted oval. So there is no such thing as a perfectly round bore except in the Delrin, or other man made materials.