The process has gotten a bit more efficient, but it still is nothing that can be run effectively in a garage. We are talking about separating not two elements, but two isotopes that behave chemically indentical and just differ in mass by 1.3% of the weight of the heavier one.

Another possibity is building a breeder reactor first to breed Plutonium.

Also, where to get Uranium ores in the first place? You can be sure that governments keep close tabs on who takes funny stones out of certain mines.