Get some crude oil. A barrel is $45 and should be plenty.
Make a fractional distillation column. You can find instructions on the internet. The part of the crude you want boils around 350 °C, ensure your heating apparatus can get this hot. Collect the 350-375 °C fraction and save it. This is the "base stock".
Make the "soap" by reacting stearic acid (tallow) with aluminum hydroxide powder (available from pet supply companies).
Combine 9 parts base stock with 1 part soap.
Simple enough?