You have several options for windmill blades. I wont go into the details of their design or construction as there is already an abundance of information on the internet about making blades.

The best blades the home builder could make are carved timber blades. With timber you can achieve a near perfect set of blades, but the process is very labour intensive and require some timber working skills, of which I have very little. My first set of timber blades were cut from 18mm ply wood, and shaped into a basic airfoil. They did workgood, but I was then lucky enough to receive a set of carved timber blade my by Dennis Latham of South Australia. These were beautifully finished and have performed better than my own blades. To find out how to make your own timber blades visit Hugh's web site.

There has been some development in using large diameter PVC pipe as blade material. By cutting a PVC pipe lengthways and reshaping the leading and trailing edge with a file, you can achieve a near perfect blade profile, and the process is so simple you could make a complete set of blades is a few hours. You would need some large diameter thick wall pipe, 250mm diameter and 10mm wall thickness. A concern it that PVC is a bit of an unknown for durability. UV light will weaken the PVC and it may shatter, sending sharp PVC splinters in all directions, so a safe operating life of 2 years or less is expected. Dennis ( above ) is also experimenting with PVC blades and is getting good results, I will update this page as his work progresses.

Another option is the use of factory made plastic blades. You can get a set of blades from Michael of EcoInn in New Zealand. He sells a set of 6 blades to make a 1.5 meter diameter propeller for $220 nz.