High vacuum equipment is fussy stuff. I built a home aluminizing vacuum system in the late 1950s, large enough for my 12.5inch mirror. You need a steel baseplate, ground flat, a molecular (langmuir-type or other) pump backed by a roughing (rotary) vacum pump. You also need a bell jar (Pyrex, thick wall) with a neoprene gasket. Also, you can make a reasonably good pressure indicator by runnng high-voltage intot he chaber. When you get a plasma keep pmping until the plasma goes out, then you rare getting close tot he vacum needed to aluminize. Typically, you hang pure aluminum wire on a tungste coil ad boil it off with low voltage hi amp current. You can make a step-down transformer.

Old Al coatings can be removed usig lye solution (sodium hydroxide)

If you want to make this stuff yourself, first read the chapter in Strong`s then try to find some books on vacuum technology that were printed in the 1950s or `60s. That technology is suitable for the amateur vacuum builder.

High vacuum is fun, but very difficult to work with - design and cleanliness is absolutely important.

Good luck!

Frank