Steve is right!!! This large turbo conductance/surface area problem is the very reason I have opt'ed for a diff pump over a Turbo!! And I 'got a hum dinger too! A huge 10" throat turbo pump, controller and cables. I back peddled to a Leybold air cooled diff pump for the bench I am working on right now.
I did a lot of welding and machine work this past weekend to adapt the pump to my setup. I obtained the pump from a guy selling at my Teslathon for $20.00! I spent $283.00 with Duniway just for the ISO blank, gasket, and some SS flex hose to make the adaptation, and still spent one man day at the lathe and TIG welder!
Vacuum hurts! What's more, our process is so vacuum dependant, it's a hurt that that keeps on hurting with each new idea of modification. The pain and troubles of vacuum related issues never goes away. I have a bunch of great vacuum surplus, but little seems to mate with anything else. You either get a great pump with oddball curvovac fittings or 12" ISO stuff with no chance of ever being able to buy a simple mating flange. You get a perfect Turbo pump to $25.00, but no controller. I have a friend who has shunned the vacuum fitting industry and makes all of his parts to a sort of ASA standard on his lathe from scratch in aluminum! That is the ultimate uphill battle.
Half of the stories told around the campfires on the vacuum trail are tales of woe and their solutions. Rare are the tales of jubilation and triumph right out of the chute.
Richard Hull
Created on Tuesday, March 20, 2001 4:13 PM EDT by Richard Hull