Hello Everyone -
After cleaning and reassembling the AIMS gauge head on our 20-20 MS, I'm seeing the system pump down to about 1 e-6 mtorr, but then no further. I replaced the copper seal where it bolts to the flange on the flight tube, but not the smaller copper seal at the other end - it is secured by a big hex nut. I'm leery of overtightening; I've snugged it about a 1/16 turn past finger tight, and then after it wasn't pumping down, another 1/16 turn.
Question: should I keep tightening or replace that little seal?
I wish I'd remembered post #011507 in the archive (subject: Physical/violent solution to Edwards Active Pressure Gauge problem), where the alternative to shutting down and cleaning is described: whacking it with a spanner.
Harry W. Read, PhD
Dept of Soil Science
University of Wisconsin-Madison
1525 Observatory Drive
Madison, WI 53706 USA