Subject: i have made a van de graaff generator and it only makes small sparks.

it is quiet large and runs on an old pump motor.i used two metal salad bowls 
for the top sphere and a piece of jelly rubber(still in tube form)about two 
meters long.the bottom roller is nylon wich i got from an old cutting 
board.the top is metal with a little grove in it to make it stay in the 
position.i have tried to clear it from sharp edges but still not much luck.it 
still makes sparks about 2cm long is this normal or is my expectations way to 
high.the van de graaff itself is approximately 1 and 1/2 meters high.i must 
admit the wire brush is quiet bad quality, i made it out of a piece of thin un 
insulated wirebended and folded into a brush.the main tube is pvc pipe but 
when i run the machine i feel that static e field all the way down the 
pipe.there is absolutely no humidity.i hope i told you enough information.
please help me. john.
p.s top site. i realy enjoy it,thanks.

Re: i have made a van de graaff generator and it only makes small sparks.