When you're first starting out with a wind generator I recommend DIY PVC wind generator blades. The reason being that they are quite easy to build and they can be built fairly cheaply as well.
When I was building my first wind generator I really didn't have the money for a nice set of blades, so I had to find a way to make some decent blades. After doing quite a bit of research I found that PVC is widely used to make decent quality wind generator blades.
You may be asking "why not wood?". Well, I did make some wooden blades once which worked very well. The only problem is that they would always get a little chip in them which would pierce the watertight coating. The blade would start to absorb moisture and the wind generator was very unbalanced. I have heard of people letting this go on to long and the blade would snap off. For this reason I don't recommend anybody build wooden wind generator blades... they're just too dangerous.
Back to DIY PVC wind generator blades though. These blades work pretty well for wind generators with a diameter of less than 6'. That means that each blade is 3 feet long or less. I've found that if you try to go any bigger the blades bend and wobble to much.
The PVC is actually cut off centered. What I mean by that is a centerline is drawn down the pipe and the blades are off centered from that. After quite a bit of experimentation I've found that they are quite a bit more efficient with this design.
After your blades are cut you do need to sand them down. If you smooth the blade and the edges so that they're nice and rounded they will move through the wind better (which will produce more power). It doesn't take that long to do, but the results are worth it.
Before you can mount your blades you will also need to apply a couple coats of UV protective paint (Tremclad works good). Pretty much any paint will work fine as long as it's rated for exterior and has the UV protection. Why do you need this paint? Well, PVC is strong, but the suns rays make it brittle. After a long time your blades are liable to break (I know this from experience); however, by applying this coat of paint you solve this problem.
Now you can mount your blades to your hub. It's a fairly straightforward job... simply drill a couple holes and bolt everything together.
Before you mount your blades on your motor you should balance them first. I usually mount them on something that spins (steel rod with some pillow block bearings) and just spin and mark which blade is on the bottom. If it's consistent I'll remove a little weight and repeat the process.
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