GLASS ENGINEERING FOR CATHODE RAY TUBE MANUFACTURE (v)

The last stage in the preparation of the CRT bulb was the application of an internal graphite coating which forms in part the connection between the EHT terminal and the final anode.   This was done by mounting the bulb into a lathe and whilst rotating it, a flexible handled directable brush loaded with colloidal graphite paste was pushed into the tube neck and thence into the bulb then manipulated to coat all internal surfaces of the bulb except the faceplate and here is a picture of Lester Creed, graphite coating at Mitcham during the early 1950s.   

The bulb was removed from the lathe and placed on a suspension carousel which transported the bulbs through a tunnel furnace where the grpahite coating was dried and the faceplate luminescent layer was hardened at which point - we have a finished bulb - simples as the meercats say!

Next time we'll look at the other major component of the CRT - the electron gun.