Hi esc.
I built my first dual rotor in 2005. I used the HF ceramics. I actuly got mine at Lowes, same magnet though.
I had the same idea. I didn't want to use expencive parts on my first dual rotor build and conciderd it to be a training exerzise.
I built the normal 12 magnet per disc and 9 coils with one big eception. I used 24 ga. wire.
The small wire worked very well because of 1 very important fact. I wound each coil with 350 turns. Then the biggy, I used a small 6 amp fullwave bridge rectifier on each coil.
Its called "Jerry Rigged" as mentioned by the guys above. 24 ga. sounds very small but when "Jerry Rigged" with 9 coils esentualy wired in perelell its equal to about 14.5 ga. wire.
24 ga. is 404 circular mills X 9 = 3636 circular mills. 14 ga. is 4107 circular mills, 15 ga. is 3257 circular mills.
I salvaged the fullwave bridge rectifiers from old garbage disposal motors from dumpster diving( free is a very good price). These must be the dc pm type motors. About 1/4 of all garbage disposals use these.
Hiker inspiered me to use old saw blades, never again. They were way to hard to machine.
Use some old brake discs they are typicaly free also. I made mine 10"
I used my 4ft "Jerry Blades". PVC blades will work very well.
A pipe blade that has been way over looked here is the PVC foam filled pipe. Its about 5/16" thick and very riged. I have pictures.
Speaking of pictures, I was just looking at my 2005 diary on this genny and most of the pictures in that story are gone but here is the story. This may take a long time to load. I made my picture files to large then and that may be why so many pictures are missing.
http://www.fieldlines.com/story/2005/1/30/4118/94606
I'm curently building aa new dual disc alt with 14 ceramic HF magets per disc and 11 coils and yes "Jerry Rigged".
The power #s are in that diary.
JK TAS Jerry