There is a newer glass diffusion pump that is available. It was designed by
the glassblower here at Arizona State. It works better than Hg, uses oil
instead,is air cooled and would be cheaper than both metal diffusion or
turbo pumps. There is an article on how to make them if people wantto
employ their own glassblowers or he makes them and sells them.
Contact me personally and I can put you in touch with him.
Arizona State University