In search of...25AP22 DUD, for it's safety glass.
 

Hi, all. Came across a set that is in need of a safety glass for the 25AP22. Any help is appreciated, I recycled all my dud tubes, without keeping at least one spare safety glass. Thank you. P.S. Posted in here by mistake, It's rectangular as you may know. 1967...

You know, the minute you toss something, a need shows up for it.
PM me if you may have something to offer.

I have one of those CRTs that is dying on a brightener. If I had a good replacement for that CRT I'd offer you the safety glass.

If you pressure band it, you won't need a bonded face.

Thank you, all. Seems it was not cracked at all. Optical illusion from the PVA material.

do you have details on how this is done? I recently had a 25AP22 implode while removing a safety lens. I would like to band it BEFORE removing the glass for implosion protection but I have no idea about the type of band, where you get it, the tool to install it. They look like simple metal strapping, but again I do not know the details.

Use the original mounting band, that came with the set.
If you look at the mounting band used on the newer CRT's, you'll see it's either crimped or spot-welded. Also the larger ones have some kind of an epoxy cement as well.

I had assumed the safety band for implosion protection was tensioned much more than just the mount band of a boned face set?

If my assumption is incorrect, then next time I remove a lens I will just leave the mount hardware attached during the removal process (couldn't hurt anyway).

A 23V safety glass will work for that CRT

...

Ok then back to the orig question how to correctly apply a tension band. Maybe someone that knows how to contact Scotty could fine out?

I know I would feel a lot more comfortable with a tension band on a bonded face CRT (when removing the lens that is), esp after my latest attempt, it sounded like a IED going off in the back yard, I was lucky, only got a minor cut on my arm, there where some pretty big chunks of glass several feet from the implosion.

http://www.youtube.com/watch?v=lRJ0otqgmYs


here is the lost CRT too bad it tested great.

I don't think it's safe to try putting a tension band on a tube not designed for it. It may do nothing useful, or if you really can achieve full tension, it may stress the tube excessively at some points where it wasn't designed to take it.

I don't know this for a fact, but seem to recall "somewhere" that hawkeye used to add the bands to previously bonded screen CRT's when rebuilding (and not rebond the lens).

Again I can not be sure. This would be a great question for Scotty.

oh well I forgot all this

http://www.videokarma.org/showthread.php?t=249487

now just have to go thru it again and see if we got a 'scotty" response.

a lot of it talks about roundie color tubes though, which I think its safe to say do NOT need a band (I don't thin I have ever seen a banded roundie). However I was not able to find much talk about rectangle color tubes.

you darn tootin it will implode. not any fun cleaning up the mess either. steve

I think they were tension banded before they were evacuated. A lot less danger them.
The rebuilder that I was buying from several years ago, was doing the same thing, that a lot of you V-K members are doing. That is, using Scotchmount type tape and clear silicone sealant.
It's not a true implosion protection, as the glass panel is not tempered. The nasty resin is what provided the implosion protection. :yes:

I see a little education is needed here. I have over 20 + years experience in the tube rebuilding field from a plant that used to be here in Knoxville, Tn. and 20 more just hanging around because he was my friend.

LISTEN UP------DO NOT EVER TRY TO SAW OFF A PRESSURE BAND ON A LIVE TUBE!!
REPEAT---------DO NOT EVER TRY TO SAW OFF A PRESSURE BAND ON A LIVE TUBE----OR YOU WILL BE VERY SORRY!!!!

ALSO DO NOT EVER PUT A TUBE IN THE COOKING OVEN TO BE EVACUATED WITH A PRESSURE BAND STILL ON THE TUBE. THE STATEMENT FROM dieseljeep ABOVE IS FALSE.

THE SAME RESULT WILL OCCUR ON BOTH WARNINGS IF YOU DO NOT HEED THEM! BOTH STATEMENTS ARE GUARANTEED 100%


I KNOW OF TWO AMATEUR "TV REPAIRMEN" WHO THOUGHT THEY KNEW BETTER THAT WISH THEY KNEW THESE TWO FACTS YEARS AGO.

LARGE CRT'S ARE NOT TO BE PLAYED WITH IF YOU DON'T KNOW WHAT YOU ARE DOING. EVEN SCRATCHING A CRT IS VERY LIABLE TO CAUSE IT TO IMPLODE and we always disposed of scratched tubes.

Julian, please elaborate on the correct way to tension band, I like that idea, just not sure how to accomplish.

I can assure you I have no intention of removing one (tension band) from an existing CRT. roger got the message :yes:

[QUOTE=julianburke;3077081]I see a little education is needed here. I have over 20 + years experience in the tube rebuilding field from a plant that used to be here in Knoxville, Tn. and 20 more just hanging around because he was my friend.




ALSO DO NOT EVER PUT A TUBE IN THE COOKING OVEN TO BE EVACUATED WITH A PRESSURE BAND STILL ON THE TUBE. THE STATEMENT FROM dieseljeep ABOVE IS FALSE.

I have a poor track record this year!
I was wrong twice already. :sigh:

Pressure banding
 

Pressure banding was a rather easy finishing step. The outside faceplate was wrapped with a clear plastic tape much like packing tape. The banding material was steel package strapping and we used a Pneumatic Strapping Tool Air Bander Strap Tensioner and I forgot what it was set at but it was very tight. We used a jig to hold the mounting ears in place. The theory is that if the side of the tube cannot expand, and the faceplate is hit, it cannot implode. Striking the faceplate makes the sides expand and it will implode unless the strapping prevents that.

After the tube is let down to air (nitrogen) the pressure band is now removed; not just the fact that it has to be removed before evacuating & cooking but this has to be done so that it fits perfectly into the vertical lathe to weld on some new neck glass stock and to insert the new gun mount and annealing to the button on the gun mount. You cannot make the tube turn true in the lathe with the band still on it.

For some reason if the strap is suddenly cut on a live tube, the sides will expand suddenly and unevenly which will almost guarantee an implosion. I have seen this happen several times by repairmen trying to remove the mounting ears to fit in another application which results in disaster!