On Fri, 14 Dec 2007 19:51:54 -0600, "jusme" wrote:

Does anyone have a centrifuge capable of filtering waste vegetable oil?

Centrifuges need to spin pretty fast. When i was in the US Navy, there
wee two different lube oil separators. One was made by Sharples and
the other was a Delaval. They spun the oil real fast and separated the
oil from water and contaminants.
The basic cylinder has a dam in the top so it would keep a prime of
water in the cylinder. When you started the machine up, the cylinder
was dry. After it got up to speed, a bucket of water was poured into
the priming hole. That filled the cylinder with water. The excess
water was expelled out the top of the cylinder until there was a wall
of water inside the cylinder. Then the suction valve was opened and
the cylinder filled with a wall of oil, inside the diameter of the
water wall.
There was a three-wing assembly in the Sharples that spun the oil and
the water at the same speed. The Delaval had a stack of what looked
like funnels upside down to spin the oil and water. Any water in the
oil would spin outward and go into the wall of water already in the
cylinder. Any dirt would move through the wall of water and stick to
the inside of the cylinder.
They listed several sizes of dams for the cylinders. The dams are for
different viscosities of oil.

You can see what one looks like here.
http://www.aaronequipment.com/UsedEq...per/19780.html

As you can see, this would be pretty hard to build.
So what are you trying to acomplish?

If your just trying to clean up the oil before burning it in your
diesel truck, Heat to 180 deg in the tank for a few days and all the
stuff will settle out.