[Argus25]

This could be an interesting topic.

I noticed in early American TV's the CRT face was protected by a twin layer of laminated glass (RCA 621TS for example). Though some sets used an acrylic like plastic, that would go hazy with age.

Later on the CRT's, both monochrome & color were made with much thicker faceplates and had integral implosion protection and didn't require a cover of any kind. The face was exposed to the user to clean (or scratch) etc.

A number of other CRT's had a "Bonded Faceplate" with a sheet of tough glass that matched the curvature of the CRT's faceplate glued on with an adhesive.

The original CRT in my Conrac monitor was a green phosphor type. It had a glue bonded implosion screen (I have described this monitor an another thread). When I replaced this CRT with a P4 (white) phosphor type, I used a type without a bonded faceplate and it made me wonder, because the face was then exposed to knocks & scratches.

This is something to give thought to with any project using a CRT where it might have a vulnerable faceplate.

So I decided to organize an implosion screen from 5mm acrylic. The first attempt was laser cut out of transparent (non tinted) material. I didn't like it much because the laser cut edge had microscopic ridges. I wanted a clear light blue, but I couldn't get the material here, I had to order it from the UK.

The pale blue tinted material was then cut the old fashioned way mechanically with a router and the edges polished with polishing compound at the local plastics company, giving a much better finish than the laser cut. Pictures attached. So I think the CRT faceplate is better protected now.

Photos attached of the two attempts at the implosion screen, clear & pale blue. It simply mounts under the existing front panel handles on the monitor.It includes 4 extra holes so the 4 CRT release screws still operate.

(This monitor was worth the work, also shown are images it produces with outstanding brightness, contrast, focus, resolution & scanning linearity, plus this unit has the best black level clamp on the planet).