B&W CRT Cataracts/Bubbling under glass

[austvarchive]

I wanted to ask a question about CRT cataracts..

A lot of my broadcast cameras have this issue on viewfinder tubes, for example the TK45's and marconis from the 70's, on the tk45's its delaminating in the form of more of a bubbling look, where as on the marconis, it is doing so in a yucky crap smearing look or pattern in the middle, either way its the same issue.

I've read some people have success simply by placing the CRT face down in some water or spirits or some other solvent and leaving for long periods?

My worry though is: is the front glass there for "safety" reasons, in these small 70's B&W tubes, and if its removed does it mean its more dangerous in terms of implosion protection? - or do you put the glass back on? I'm just wondering if you remove the glass how it affects re-installation of the tube since it will be lsightly smaller at the front..or does this not affect things in most cases?

I've a number of supposedly brand new tubes but they are showing the same early signs on delamination also creeping in from the corners.

[bgadow]

The usual routine is to reattach the safety glass, after cleaning everything. Instead of a full layer of bonding agent across the whole face (as original) you can just put a bead of clear silicone around the perimeter. Use matchsticks or something similiar as spacers. You shouldn't forgo the glass completely, due to safety concerns.