[Tom_Ryan]

[QUOTE=frenchy][QUOTE=On the subject of phosphors, I've had the unpleasant experience of discovering the non-aluminized black & white tube phosphor the easiest to damage if you suddenly break the seal off nipple at the base of the gun. You can blow away a circular patch of phosphor several inches in diameter off the face plate.>>>

Probably is a way to do it by putting some flexible filter or device over the nipple so when it is broken, the air has to go thru the filter or something like that to slow down the de-vacuuming of the tube (?) Maybe just a little rubber hose slipped over the nipple with a filter or pinhole plugged into the other end of the hose.[/QUOTE]

Frenchy, the early non-aluminized tubes were coated with phosphor that were typically atomized or gravimetrically settled onto the face plate via a liquid alcohol suspension. Baking the tube during evacuation removed the volitials and leaves the phoshpor on the face plate. The only practical way to bring these tubes up to air without disturbing the phosphor is using a very slow leak. Specialty equipment used during rebuilding usually places the entire tube in a vacuum before the vacuum in the tube is breached (usually the neck is cut off to replace the gun assembly). Using a filter on the nipple I doubt would work as it takes only the smallest amount of air rushing in at about 300 miles per hour to disturb the phosphor.

Remember there's about 1,400 lbs/ square inch pushing down on a CRT from the outside world. Ya gotta grab onto ur hose and squeeze it real tight to slow'r down!