Step 4: Construct the blades

The blades are 2" x 6" pine, cut at 10 degrees on a table saw, and sanded into a rough airfoil. Not perfect, but close enough.

More can be found at



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TheStudio72 years ago
This is one awesome instructable. THANK YOU.

Your windmill looks very neat.

noobie questions:

1. Approximately how much are the 24 magnets these days?
2. What brand of resin/hardener did you use?

sspence (author)  greenbuilder342 years ago
Magnets run about $500 or so, and the resin we picked up at the auto parts store.
I've found http://www.otherpower.com/ a decent-resource on "off-grid living".

Do you have any better images of the blades besides the first one?
sspence (author)  dairyfarmer7774 years ago
carbon fiber would probably be best type made as air foil, probably super expensive unless you knew how to do it yourself.
carbon fiber is hella expensive due to a nearly decade long global shortage... not to mention extremely difficult to work with in comparison to just good old plain spun silica fiberglass.. a couple of layers of chopped mat in between two layers of regular ol' 4 and 4 would do the trick... and he could probably get away with using the same resin he is pouring over the magnets and coils... still pricey...
sspence (author)  thirtyfivefox4 years ago
a 2" x 6" is sufficient for us.
I have a friend who does (used to do?) fiberglass, carbon fiber and aluminum for custom aircraft cowlings and he claimed for most things fiberglass was close enough and its easier to work with...just needs a framework for support, make it hollow.
Bob1746 years ago
I could not find any discussion on connecting the coils for 3 phase power output, and for connecting the rectifying diodes (how many are needed?). I could not find any information on actual performance (watts at say 10 mph wind speed,
sspence (author)  Bob1746 years ago
there are 9 coils, 3 phases of 3 in series. every third coil is connected in series. the diode bridge is a 3 phase bridge, just like a car alternator. read hugh piggots book, or dan fink's.
zihanjj sspence5 years ago
 will it be simple to use a Car Alternator, but ofcourse an additional power should goto the Field coils of the Alternator, but it reduce the weight of the Generator and give's you more control. Also a cut-off if the wind speed is way too high. 
sspence (author)  zihanjj5 years ago
 Car alternators make lousy wind turbines and are not, and should not be used. Not just the field coil issue, like you mentioned, but also rpm range is all wrong.
Unless you live in an area that generates 250+ mph winds steadily and use REALLY short blades ;-)
phillip19666 years ago
how do you make the blade hub?
sspence (author)  phillip19666 years ago
We had the triangular plates cut for us. It's simple 1/4" steel with holes drilled for the 3 blades. Will be uploading that info soon.

sspence (author)  lwilliamson4 years ago
um, hi?
aistech4 years ago
hello im new to wind power could i build a 3 phase generator like the ones all over the net rectifiy it to dc power then put it through an inverter to tie into my house power to lower my usage

sspence (author)  aistech4 years ago
Yes. You will need a battery bank, and a battery/grid tie inverter, like the Outback.
well done, theres a few things I don't quite get about the coils & theres connection but you've explained it fairly well, you'll need more schooling to be able to explain it to every body, lol . I have a 40 pound 12volt DC motor can I use it for a gen motor, it looks like a small golfcart motor, should I spin the shaft I see if I get power from the leads?
Picture 013.jpg
If it is permanent magnet yes, if not your probably out of luck. If it has any pull on metal that should give you an idea, or just see if it sparks when you spin it.
greedpower4 years ago
Could you please tell me why you would not recommend using or making PVC blades? Thanks.
sspence (author)  greedpower4 years ago
They don't hold up. PVC degrades in sunlight and a 8' blade would flex too much and snap.
kaleemullaj5 years ago
goooooooood sutpindo fantastical fabulous..................
but how do u store the current...........?
or how2 use da current.........?
sspence (author)  kaleemullaj5 years ago
 power is stored in batteries, and converted to 120vac with an inverter.
hi .. nice  u r project can u tell me  25 kw  5.6 mtr blade balancing  mathod ..


sspence (author)  mahesh.ganpate5 years ago
 with our blades, we spin them by hand, and the heavy one stops on the bottom, so we add weight to one of the others, and keep doing that until there's no pattern to where it stops.
vordnorf5 years ago
 You power your home entirely with renewables and they all power a series of batteries which act as your store. However, batteries generally degrade over time. What sort of batteries do you use and how long is there lifespan?
sspence (author)  vordnorf5 years ago
 I'm currently using deep cycle lead acid batteries, with a life span of 12-15 years. My next set will be NiFe, with a life span of 50+ years.
 Ah right. Guess I should go for the NiFe one's then. Thanks for the help and the advice you're a true pioneer.
sspence (author)  vordnorf5 years ago
 They require a custom charge profile. Use Outback charge controllers and inverters.

I have a discussion forum for topics like this. If you’re interested in “Sustainable Energy” stop by. http://www.voltsandboltsonline.com/   
Nice WindGen by the way!
sspence (author)  VoltsAndBolts5 years ago
kessler14925 years ago
I am serious about building one of these, how long has this model been in operation (how is it holding up), and what kind of regular maintenance is required. how many batteries would it charge, I'm assuming it would need a 2000 watt inverter (just to be safe). and could I build my own control box?
sspence (author)  kessler14925 years ago
It doesn't need an inverter at all. for a control, I'd suggest a diversion controller like the xantex c60, or the outback fm-60 or 80 in diversion mode. we have had these in the air for several years. yearly greasing and blade painting is all that is necessary.
from what I understand, first you have the wind turbine that is hooked to control then it goes to charge the batteries, then don't you need an inverter before I hooked it into the power system of my house, to change it to AC? My other question you did not answer is how many batteries will it charge? Also my power consumption is around 550 KW per month would one wind tubine and solar panels be enough to power it?What model of harley davison wheel bearings is it? I am planning on getting marine batteries, for powering a house unless you would suggest 24 volt batteries, sorry you are one of the few that has experience powering a house so I plan on picking your brain!
sspence (author)  kessler14925 years ago
the turbine is connected to the batteries. the diversion controller connects a heavy load when the batteries get full, preventing over charge. the job of an inverter is to convert battery power (low voltage dc) to house current (high voltage ac). the inverter has nothing to do with the wind turbine. I told you how many batteries I have. how many it will charge is determined by how much wind you have, and how much power you remove from the batteries (number of batteries is immaterial, it's capacity removed that needs to be replaced). there's no set formula of wind turbine size to battery size. I suggest 6v batteries (trojan t-105 or L16), as deep cycle batteries do not come in 24v typically. Marine batteries are a starting hybrid, not appropriate for off grid use.
so what is my first step, finding out how much wind I have? How can I find that out? And how do I figure out capacity?
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