I started with an Appleseed; but be a bit careful. Start with a new waterheater- used ones will have sediment issues for ever and ever no matter what you do. I know the plans have changed, but the plumbing can be a bit sketchy and the catalyst system could be a lot safer.
Or you could use polyethylene.
www.plastic-mart.com (I have no affiliation with them whatsoever) has a biodiesel package- two tanks and stands for $225. Pump and plumbing will run another $100- $200. Get a metal 55-gallon drum and a barrel heater and preheat your oil in it. The poly tank will withstand 140-degrees, and the reaction will cook off in under 2 hours at that temp.
Just for yappin', I've been making biodiesel for over 3 years in poly tanks, in temps down into the 40's with no quality issues. That being said, I do use a two-reaction process; in the first reaction, I use 75% of the catalyst and let it work overnight. The next day, I drain the glycerine, mix the remainder of the catalyst (fresh, not leftover) and reprocess. I found that this gives a greater glycerine yield, therefore, a more complete reaction.
I also wash it a bit differently, too- I add about 30% hot water by volume, then mix it with a "squirrel cage"-type paint stirrer until it looks like coffee with milk. Let it settle, drain, and repeat. It dries much more quickly than "mist washed" bio.
My biodiesel looks, tests and runs better than any pump bio I've found. If you put it in a jar, add distilled water, and shake it, it separates quickly and the water stays clear.
The bio looks like clear applejuice, smells like money (saved).
