Check out this thread from the other day:
http://www.penturners.org/forum/topic.asp?TOPIC_ID=6174&SearchTerms=HF
At the bottom of the first page is a link to Joe's workshop.It has plans for two vacuum pump.
One uses a compressor to pull a vacuum through a venturi.
The site sells a similar venturi as the one from HF.
I use a very crude set up without the automatic switching.
Though this will put a stabilizing mixture into blanks it cannot be compared to the results you will get from pressurized stabilization.
I have no idea what percent of acetone plexi I use(Volatiles/solids.Assume I use a 50% mixture,once the acetone evaporates only half of the solution is left in the material(plexi, or solids)
This is no where what the end product of a pressurized process will yield.
It works for what I need, but I do know it's limitations.