RCA cataract removal

[Electronic M]

Originally Posted by DaveWM

Perhaps, but I am not aware of any non bonded or non banded rectangle color tubes out there in sets as standard equipment. All the ones that has separate glass were that I can think of were roundies, which I think may have different mechanical qualities that the rectangles as far as likely implosion stresses.

I have seen some old BW tubes (rectangle) but IIRC the glass in front of them was some kind of tempered or other form of safety glass. I don't think the rectangle color tube glass has any special safety qualities other than to act as a part of a bonded system.

I don't think the use of silicone around the edge provides the same protection as the bonding. But I am not hear to argue the point, as its been discussed many times before. I also don't condemn the practice just saying I would be leary of selling one that way, too old to spend time in from of a civil jury trying to explain it.

I've busted the safety glass on both round and rectangular color CRTs and I can tell you the glass breaks the same way, and is almost certainly the same type/formula of glass.

I can understand your caution, but eventually that is something all of us will not be able afford as replacement CRTs dry up.

Any implosion with or without safety glass is going to throw glass out the front of the set. Members here have told stories of mid 50's sets with separate glass as well as color tubes with bonded glass spontaneously imploding and throwing glass out the front of the set. Any set even untouched factory originals have some chance of imploding spontaneously...In 99.99% of CRTs implosion is either an act of god of an act of the human(s) around the CRT when it goes off. The only way to 100% avoid it is to not own pre tension band era CRTs.... They way I see it if a CRT is no more dangerous than other models I have that are ~10-20 years older then it is plenty good enough.

I never let implosion (on completed sets) worry me...Hell, I've got a caulked rectangular tube within ~3' of my bed and am around it 6-24 hours a day every day except ~2 weeks of the year vacationing. I'm more likely to be struck by lightning than even mildly injured by an implosion from a de-catted CRT that is mounted in a TV....Implosion injury during the removal process however is a lot more likely than lightning especially RCA tubes that require heating.

[WISCOJIM]

Originally Posted by DaveWM

I don't think the use of silicone around the edge provides the same protection as the bonding.

I definitely agree with you.

I never saw removing a cataract and only sealing the edge as a good solution. I admit I have done this myself in the past, but have always had serious safety doubts.

The way safety glass is made is to have a plasticized layer between two sheets of glass. It is this middle layer that makes it safety glass. That layer is what holds it together so that glass doesn't fly around in loose pieces.

When you remove the bonding agent, you have just ended up with two individual pieces of glass, free to shatter and fly wherever.

Remember that the bonding was there for more than just to hold a cover glass in place. It was to create a safety glass by bonding the cover glass and the CRT face together.

Removing the bonding agent and not replacing it gives you very little implosion protection.

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[DaveWM]

main point is to the OP, just be very careful, you can become complacent (I did) with success to the point of not exercising real caution. Lots of ways you can get hurt by these old TV's CRT is just one of them.

[Findm-Keepm]

It's a false sense of security with having an intact safety glass bonded to the CRT, as implosion protection with bonded safety glass is only present from the front and when the CRT is installed. Anytime a CRT is removed from the cabinet, all of it poses a serious implosion threat. Glass shards from an implosion fly everywhere, and have no care for whatever is in their way.

Having had a 25" CRT implode just inches from me, I can tell you I now take every measure of safety seriously.

Be v-e-w-y careful, as Elmer would say....

[andy]

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[Electronic M]

Originally Posted by andy

I have a Sears (Sanyo) 19" rectangular color set from the late 60's with a non-bonded safety glass. It has no tension band, and is definitely original. The safety glass is actually attached to the front bezel rather than the CRT. It's a very old fashioned design. Unfortunately, I've never been able to get a good picture out of it due to an IF, or tuner issue.

I know the older flat glass was usually laminated safety glass, but the later curved glass is just one piece. Has anyone compared the safety glass of a 21FBP22 to the one from a 21FJP22? Are they the same thickness and type of glass (apart from the FJP being tinted and etched)?

I was under the impression that one of the reasons for bonding the safety glass was to improve the optical qualities (no internal reflections to blur the image, and impossible for dust to enter).

I'm sure removing the bonding does make it less safe, but it's still better than nothing, and better than no CRT at all. It may be just as safe (or dangerous) as a 21FBP22. If nothing else, it protects the CRT from scratches and minor impacts that could cause an implosion.

Yes and Yes.

[TUD1]

It was in the 80's today, so I decided it's a nice day for another cataract surgery. This time, I put the tube in the hole I dug with a tire, instead of on the bathroom floor. Once again, I got the glass and glue off very easily. The glue came off again in one big sheet.

[TUD1]

Just siliconed the glass back on. I put the silicone on a little heavy in a few places, but it's beacause it's dark outside now and I couldn't see.

[TUD1]

Here's how the siliconed tube looks with the mask over it. Not nearly as bad as a cataract, but still noticable. I might get a razor blade and cut the silicone and try again.

[Findm-Keepm]

I've always wanted to try PVB resin to tack the safety glass back on to the face of the CRT. Something like this:

http://www.ebay.com/itm/Re-Repair-Re...4&var=&vxp=mtr

I have no idea what version of the stuff I'd try - or what "CPS" is...

I'd go with just a thin line along the edges, and lower the safety glass onto the CRT carefully. It cures optically clear, so not much "show" and the safety plate would be within a millimeter of the CRT face, so no "shadow effect" caused by a gap.

My 21FJP in my CTC16 has a cataract, but it's in storage right now, so I'm a long way off from trying.

[old_tv_nut]

From what I can find, cps stands for centipoise, a measure of viscosity.

[Kevin Kuehn]

Maybe fasten the glass back on using a few small evenly spaced pieces of double sided tape, then follow up with a fine bead of caulk around the outside to seal the dust out, or maybe even just use clear tape. I highly doubt silicone caulk will add much implosion protection. I'm thinking avoid the whole caulk mess.

[DaveWM]

I just use the foam tape, single side sticking, go all around the glass (not the crt) and use packing tap to hold it in place. The foam tape spaces the glass off the crt, keeps the dust out.

[Electronic M]

Originally Posted by TUD1

Here's how the siliconed tube looks with the mask over it. Not nearly as bad as a cataract, but still noticable. I might get a razor blade and cut the silicone and try again.

I'd pop it apart, clean the caulk off and try again. I generally never re-attach the glass in low light (heck I try to only do it in direct sun) since I want to SEE that the face of the CRT and inside of the glass have absolutely zero dust or lint before I start caulking. It can take a bit of practice to do caulking right if you've never worked with it before. I tend to use 4 strips of 1/4"x1"X 1/8"thick foam double sided tape on the center of each side as spacers, then apply my caulk....With the foam If you don't quite bridge the gap you can press the glass together to get it to stick. Always cut the nozzle of the caulk so there is an opening as small or smaller than the gap and go slow...An extra 10 min of time caulking can make the difference between 'do over' and something you may never have to touch again.

I've always preferred caulk. If done right it won't be seen, and it should last the life of the tube...Unlike tape which can dry out and loose adhesion in 10-30 years.

[WISCOJIM]

Originally Posted by Electronic M

I've always preferred caulk. If done right it won't be seen, and it should last the life of the tube...Unlike tape which can dry out and loose adhesion in 10-30 years.

And you could use clear silicone caulk, rather than white!

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