Read those searches, but one problem with home-made biodiesel is the fact that you have to burn a bunch of diesel AND your time, just running around getting raw product and making finished product. Of course there are warranty issues, cold weather issues and a bunch of other considerations. I have no doubt that a few people with the right situation can pull it off economically, but most people would spend more in money and time than they would re-coup in fuel savings. Just my opinion though, I go shooting or fishing with my free time (no interest in lugging around used veggie oil when I'm not trying to make money) so I haven't really taken a close look at the options.