View Full Version : RCA cataract removal


TUD1
01-24-2017, 06:55 PM
I'm doing an experiment on RCA cataract removal. I took the 25XP22 out of my CTC-40 tonight and replaced it with a Sylvania 23VAJP22 rebuilt tube. It looks really good in the set. I put the cataracted tube in the bathtub with water. I've seen videos where people put them in water, and after a while, the cataract fell right off. I'll report back with my findings.

Electronic M
01-24-2017, 07:29 PM
YMMV...Mine sure did! I had the same tube out of a CTC-25 it sat in water for about 2-3 months. All that happened was the mounting hardware rusted.

TUD1
01-24-2017, 07:38 PM
I have no idea what YMMV means. I had to use the mounting hardware to mount the Sylvania CRT, so no problem there.

Electronic M
01-24-2017, 08:05 PM
YMMV=Your Mileage May Vary.....Google is good for acronyms and text message style gibberish.

The water never did a thing to loosen the glue on mine....All it did was invade where the glue had always been bad...

TUD1
01-24-2017, 08:13 PM
Interesting. In the video I watched, the entire piece of PVA came off in a big sheet even where it had not delaminated yet. Maybe you didn't let it sit long enough. It was an RCA tube identical to mine.

Captainclock
01-24-2017, 08:14 PM
How did you get a 23" picture tube to fit into a 25" TV? :scratch2:

TUD1
01-24-2017, 08:15 PM
25XP22 is a 23" tube.

Captainclock
01-24-2017, 08:20 PM
25XP22 is a 23" tube.

I thought the first two digits of the picture tube number indicated the size of the tube? e.g. 25xxxxx meant it was a 25" picture tube and 23xxxxx meant it was a 23" picture tube and 19xxxxxx meant it was a 19" picture tube.

TUD1
01-24-2017, 08:39 PM
That's correct. Before ~1970, manufacturers lied about the size. The government made them tell the truth.

bgadow
01-24-2017, 08:39 PM
In about 1970 or so the Federal Trade Commission came up with a ruling that said the advertised size must match the VIEWABLE part of the picture tube and not the overall diagonal measurement of the face. This cut down the size of a 25" to 23". After the change 25xxxx became 23Vxxx. Later, bigger tubes came out that were 25Vxxx. The "V" is the key!

TUD1, you type quicker than I do!

bgadow
01-24-2017, 08:44 PM
The PVA (adhesive) seamed to vary a lot, and I guess it's condition after all these years matters, too. I first discovered water would work when I dug out an old RCA round tube that I'd left sitting out in the woods for a number of years. The PVA had turned to jelly. I did one in a kiddie pool and it worked after 2-3 weeks, though still took some prodding. Others haven't responded nearly so well, especially the green type used by Zenith and others.

Findm-Keepm
01-24-2017, 08:45 PM
23V=25" tube. You have a 23VAJP22, never seen a 23AJP22, just the 23VAJP22 and a 25AJP22.....

23VAL/VATP22 were standard tubes in the 80s to replace the 25AP/XP22 CRTs.

tom.j.fla
01-24-2017, 08:48 PM
By current FTC standards a 25XP22 is a 23 inch crt as in 23VAJP22. The "V" is to show current standard of viewable area. All the best, Tom.J

Electronic M
01-24-2017, 09:47 PM
IIRC the government put the viewable area law in place in 1968.

I've put that tube in for the longest time I'd heard used. It belonged to a client so I could only wait so long.

Zenith CRTs can be done cool, safe, and reliably by cutting the soft glue with a guitar string....I'll take a dozen Zenith cat removal jobs over one RCA any day.

MadMan
01-24-2017, 11:38 PM
Is the screen cover usually glass or plastic on these sets? I've honestly never seen one in person. I know they're bonded with clear... adhesive or whatever, but that's it lol

TUD1
01-24-2017, 11:57 PM
I'm not aware of any plastic safety glasses. But then, there might be some out there.

Electronic M
01-25-2017, 12:17 AM
Every bonded-to-CRT-face safety glass I've seen was glass....I've seen plastic safety glass too but as a separate piece from the CRT usually mounted to the cabinet separately.

DaveWM
01-25-2017, 11:40 AM
It can take MONTHS of water soaking, really depends on how bad it is to start with (talking RCA type bonding).

I have one that has been out out side for well over a year, maybe 2, its in a foam packing case (the kind it was sold in as a rebuild). I have a funnel that catches water and drains into the face area. the pins and anode are covered in grease to prevent corrosion. I dug out some of the bad plastic to help trap the water.

I was tempted to just bury the face in the dirt (with a soft towel to protect the face) and let the microbes have a shot at it.

MadMan
01-26-2017, 02:41 AM
I don't think water will do much. Solvent would be a better bet. Diesel and kerosene are pretty safe, stable, and won't really evaporate. Dunno how good it would work, either, though. I'd imagine acetone would be the absolute best. It'll eat through damn near anything... but it's as flammable as gasoline, and it'll evaporate after a short time. It'd need to be in a sealed container, with a vent, and stored outside away from buildings and flammable things.

Have you read my name?

Or, you know, you could do THIS. (https://www.youtube.com/watch?v=32_qMSWEdjc)

Jon A.
01-26-2017, 05:41 AM
My Heathkit GR-370 came with a RCA Hi-Lite 25BCP22, unfortunately pretty much shot. I didn't know what to make of it, I couldn't see where separate safety glass was attached and the tension band was held on with bolts. The tag said it had integral implosion protection. Such a CRT seems very odd to me.

DaveWM
01-26-2017, 09:09 AM
water works just takes time, need to be patient. heat gun works but not recommended esp on a rectangle tube. ALWAYS where safety goggles regardless of method.

andy
01-26-2017, 11:30 AM
I've never had a problem with using a heat gun. It's very important not to use too much heat, and to go slowly. Use a variable temperature heat gun at around 300-400 degrees F, not a 1200 degree paint stripping gun!

DaveWM
01-26-2017, 04:57 PM
Glad for you Andy, hope you never have one go off on you.

TUD1
01-26-2017, 11:04 PM
Just checked the progress. Absolutely no difference. But that was only after 60 hours of soaking. We still have 2 months, maybe three, minimum.

DaveWM
01-26-2017, 11:46 PM
what generally happens is the bond to the glass just weakens a bit. The adhesive will not dissolve at all. Again they are all different, worse is better as far as getting them unstuck. What you don't want to do is rush it, esp the critical moment of trying to wedge off the glass. I used wood clothes pins, dig out some of the plastic that is real bad and GENTLY tap them in all around the perimeter. What you are looking for is a very slight upward pressure that is even. If you try to hard the glass will break, then you have a much harder time getting the pins located with even pressure. Once the glass is broken its 10x harder. so again you must go very slow, on a hot day and it can take hours for the slight pressure to work its magic.

Safety gear is a must, I had one go off on me, blew BIG chuncks of glass, very sharp very pointy with an explosion that sounded like an M80 at about 8" away, and it was instant. I got lucky, had my googles on, still got some pretty decent size cut on my arms. heavy chunks went 30ft away.

TUD1
01-26-2017, 11:55 PM
Dang. Thanks for the warning. I've been handling these tubes pretty gently. I know they're dangerous, but hearing somebody's account of it really brings it home. I have poor eyesight, so whenever I'm doing literally anything, I have to have my glasses on. Not that eyeglasses are going to help on the event of an implosion anyway.

Eric H
01-27-2017, 12:21 AM
I removed the cracked safety glass from a NOS Channel Master rebuilt tube a couple years ago by soaking it.
It had no cataract at all except a bit of deterioration around the cracked area where air was able to get in.

It took a couple months face down in the tub with water above the level of the screen, since the glass was already cracked I just kept breaking off bits and pieces each week as the bond came loose.
If it had been in one piece I don't know if it could have been removed without breaking it, maybe after a year of soaking but not in two months.

Eric H
01-27-2017, 12:25 AM
I don't know if this was mentioned but, most bonded tubes have clear tape around the edge to keep air and moisture out, you need to remove it or cut it for the soaking method to work.

andy
01-27-2017, 04:02 AM
CRT rebuilders must have done this all the time. Does anyone know what their method for removal was? I assume they did it after it was up to air, but they would still have needed a quick way to remove the safety glass without breaking anything.

DavGoodlin
01-27-2017, 10:09 AM
REAL Good timing on this thread. My first Cat job was easy, and certainly not the norm. Full cataracts are a sight for sore eyes LOL

But now I am working on an original RCA Hi-Lite 21FJP22 from a GE roundie, now owned by another VK member. The cataract was advance to the point where only a 15" central circle was still fully attached. PVA or polyvinyl acetate supposedly only softens in water or methyl alcohol.

I used wedges like Dave says above, but once you crack the glass its a PITA (BAM! and it happens instantly). I was definitely not patient so Ill pay the price of robbing another CRT of it's faceglass, which HAS detached 100% :)

So far, I have been using the known dry methods, heat-gun, full-time heating pad-which I highly recommend, scraper razor blades cedar shims. and finally waxed dental floss (NOT ribbon floss) to keep the faceglass warm, chip away at softened the PVA.One I busted the glass, I had to wedge it out in pieces, basically inducing cracks with 2-minute intervals of 2-3" from the heat gun.

Once I was down to a 4" piece, I stopped using the heat gun because I did not have a good way to shield the adjacent CRT glass. This morning it took only a razor blade wedge and floss to pop off the last card-sized chunk of safety glass.
Below is a picture of what I have been working on over the last week. BTW- a 5 gallon bucket is great at protecting a tube like this. But for a 25XP22, I might opt to build a stand out of 2x4's.
193552

Fortunately I too must wear glasses at all waking hours BUT safety goggles are the best practice for all of us when handling these tubes, even newer ones from the 70s onward.

DavGoodlin
01-27-2017, 10:15 AM
IIRC the government put the viewable area law in place in 1968.

I've put that tube in for the longest time I'd heard used. It belonged to a client so I could only wait so long.

Zenith CRTs can be done cool, safe, and reliably by cutting the soft glue with a guitar string....I'll take a dozen Zenith cat removal jobs over one RCA any day.

Tom, Do I recall you passing some controlled current thru that guitar string to speed the process, like from a car battery:scratch2:

Electronic M
01-27-2017, 10:34 AM
Tom, Do I recall you passing some controlled current thru that guitar string to speed the process, like from a car battery:scratch2:

I initially* designed my rig to be capable of that, but did not pass any current when I did my successful Zenith type cataract removals. I initially experimented with current, but found the wire would develop hot spots, loose tensile strength and snap well before any significant progress would be made.
I've found it works best with NO current running through the wire and the wire at ambient air temp. I've also found it unnecessary for the tube to be warm...Back in fall when it was something like 45-65 F outside at night I did a guitar string zenith cat removal with the tube at ambient temp and the wire at ambient temp and it worked fine.

Make sure you attach the wire solidly to your pull handles, and to use something more sturdy than paint stir sticks. The glue will try and hold the wire/provide a good amount of resistance to pulling so it takes a good bit of arm strength.

http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/th_ZenithCRTcateractremoval.mp4 (http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/ZenithCRTcateractremoval.mp4)

*I've long since removed the current supply from the early guitar string cataract removal rig in my video.

The guitar string method is meant for the green halo Zenith style cataracts, the white moldy RCA style is unlikely to respond well to the guitar string method.

DavGoodlin
01-27-2017, 04:53 PM
Great, I have two Zenith 25's that will need done. That yellow tint around the edge really makes the color look awful on those. Not Acceptable!

DaveWM
01-28-2017, 04:42 PM
Pretty sure how rebuilder did it has come up before. that have industrial size ovens that can heat up the entire tube very evenly, to the point where the glass just lifts off. The issue with the heat gun is presumably un uneven heat causing stress for un equal expansion of the glass. I think the roundies are generally safter than the rectangles. Later rectangles had safety banding that would compress the perimeter. I the perimeter cant expand, then the tube can not explode along the perimeter, just inward from the implosion. After having one go off on me I tend to not mess with it anymore. just look for a decent CRT and live with it. Oh one more thing, if you are using heat clearly do not use a damp cloth to cool it down, again rapid uneven heat and cool is not what you want.

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

check out the burnt shadow mask..

Findm-Keepm
01-28-2017, 06:13 PM
Pretty sure how rebuilder did it has come up before. that have industrial size ovens that can heat up the entire tube very evenly, to the point where the glass just lifts off.



Sony even patented the process. Rauland had been using it for years, but never sought a patent. I don't know if there was ever a patent fight, but both of them used the same process - heat it up.

PVB used in the first rectangular tubes is impervious to water. I'm sure that if someone knew the exact brand of PVB, a solvent is readily available - whether it be ammonia, acetic acid, some alcohol based solvent, or some hydrocarbon solvent.

The same PVB is used with early automobile windshields where they bonded the safety glass to the oven glass and needed an optically clear adhesive.

https://en.wikipedia.org/wiki/Polyvinyl_butyral

Findm-Keepm
01-28-2017, 06:15 PM
BLASTED! Here's RCA's method...

MadMan
01-28-2017, 09:35 PM
BLASTED! Here's RCA's method...

The tube is seated in the masking box so that only the glass cap is exposed. Abrasive particles are then blown from the nozzle and upon the cap... To erode the cap by pulverization thereof, the nozzle is moved back and forth...

So basically they sandblast the safety glass until it doesn't exist anymore?

https://dl.dropboxusercontent.com/u/37540750/_ponies/sweetie%20seems%20legit.png

TUD1
02-01-2017, 08:31 PM
The water soak method is already showing sure signs of progress. Looked at it again today, and I was able to easily remove two huge chunks from the corners. I gently put some clothes pins in, and I could see where it was starting to come apart more.

DaveWM
02-02-2017, 09:22 AM
leave it soak for a couple weeks (or months since its still cold out). Summer time is best for doing the removal, you put it out in the sun, put clips all around the perimeter, just a little bit of pressure from the clips bearing on the glass with as much contact area as possible. Slowly the glass will begin to let go, you can see the de-lamination progress as shadow lines will form on the face of the crt. As this happens the clips will get loose, tapping them in gently until just firm and walk away. The process can take hours. Best to do when its at least 90f outside in full sun. the most important thing is not to get impatient.

TUD1
02-04-2017, 04:30 PM
Had a good idea today while I was burying the mouse I finally caught. I dug a hole in the ground, put a tire on top for safety, and voila, poor man's cataract removal studio. I'm going to get a heat gun one of these days and start doing cataract surgeries that way. Water is taking too long.

Electronic M
02-04-2017, 07:34 PM
Had a good idea today while I was burying the mouse I finally caught. I dug a hole in the ground, put a tire on top for safety, and voila, poor man's cataract removal studio. I'm going to get a heat gun one of these days and start doing cataract surgeries that way. Water is taking too long.

That looks like a Zenith type cataract. Better to get some #18 steel guitar string (type that has a smooth surface), screws, and small pieces of wood to use as handles. Using the guitar string method (which I linked a video demonstrating above) is about 10X safer/more likely to completely succeed than using a heat gun, and bit faster.

TUD1
02-04-2017, 08:31 PM
That tube is an RCA Colorama that is graveyard dead. It's my guinea pig CRT. At 8 volts, it has no emmision.

mrjukebox160
02-04-2017, 08:57 PM
I have never seen an RCA tube turn green. Strange.

Electronic M
02-04-2017, 09:52 PM
It is possible RCA had a shortage and re-labeled another makers' tube or used Zenith type PVA. Peel the tape on the edge and poke the glue...If it is soft and springy like chewing gum when you first get it soft, then it is Zenith type glue (which was not used exclusively on Zenith tubes), but if it is hard as tire tread rubber then it is RCA type glue (which was not used exclusively by RCA). Neither Zenith nor RCA were the exclusive maker using that glue, and IIRC both makers used other types of glue occasionally (very rare to find).

I've also seen smaller makes use something in between or outside of the two types normally encountered and thought of as Being either RCA or Zenith....Those can be a bitch.

Regardless of make/label the yellow/green springy stuff is what we call Zenith type, and the hard stuff that turns white/black and moldy is RCA type. Ignore the makers mark and look at the glue!

TUD1
02-05-2017, 02:45 PM
Went to Lowe's and got a heat gun today. It's kind of a piece of crap, but I'm sure it will at least last for two cataract removals.

DaveWM
02-05-2017, 02:46 PM
Had a good idea today while I was burying the mouse I finally caught. I dug a hole in the ground, put a tire on top for safety, and voila, poor man's cataract removal studio. I'm going to get a heat gun one of these days and start doing cataract surgeries that way. Water is taking too long.

would not recommend water or heat on that one. as mentioned a simple steel wire will cut thru it. Green is zenith type adhesive, stays soft and can be cut.

WISCOJIM
02-05-2017, 02:51 PM
Went to Lowe's and got a heat gun today.Careful! If you heat it too fast or unevenly you will end up shattering it.

.

dieseljeep
02-05-2017, 03:06 PM
Went to Lowe's and got a heat gun today. It's kind of a piece of crap, but I'm sure it will at least last for two cataract removals.

It's probably a little better than the Harbor freight jobs, $8.88 on sale. They're a few years old and still going strong. They don't have a cold setting, so you have to let them cool off before putting them away. :sigh:

TUD1
02-05-2017, 03:29 PM
would not recommend water or heat on that one. as mentioned a simple steel wire will cut thru it. Green is zenith type adhesive, stays soft and can be cut.

Like I said, the Colorama is junk. I'll probably get the glass off and neck it in the backyard.

DaveWM
02-05-2017, 08:46 PM
Like I said, the Colorama is junk. I'll probably get the glass off and neck it in the backyard.

I realize that, my point is practicing on a zenith style adhesive will not help you gain useful experience for using a heat gun on an RCA style adhesive.

Electronic M
02-05-2017, 09:15 PM
Best to use the technique that matches the type of glue. Sort of like you would not want to use carb cleaner on a mass air flow sensor, and you would not want to use sensor cleaner to clean a carb...Best to use the right tool for the job especially when the Zenith method is cheap to gear up for.

TUD1
02-06-2017, 05:47 PM
Guess what you guys! I just took a heat gun to my 1969 RCA Hi-Lite tube, and I had the glass off in half an hour. As soon as I saw the fingers meet up where it was delaminating, I heard a loud POP, and the glass fell right off. I even got the glue off in one big sheet.

Titan1a
02-06-2017, 08:15 PM
Awesome! Good show.

Electronic M
02-06-2017, 08:21 PM
Given the way it came off I guess it was RCA type glue....Odd, I've never seen RCA glue turn yellow-green like that before.

Nice job!

TUD1
02-06-2017, 08:45 PM
This tube did have the moldy RCA style. The tube you're thinking of is the 1973 Craporama tube. I haven't touched it yet.

DaveWM
02-07-2017, 09:15 AM
Guess what you guys! I just took a heat gun to my 1969 RCA Hi-Lite tube, and I had the glass off in half an hour. As soon as I saw the fingers meet up where it was delaminating, I heard a loud POP, and the glass fell right off. I even got the glue off in one big sheet.

Good job, just remember they are all different, some easy some not so much and all are dangerous so always wear at least eye protection (full face shield) and some heavy garments. There is no way to tell if one is going to implode on you, and no one has quick enough reaction time to get out of the way when it does during the removal process. One last thing to remember the CRT now has NO implosion protection. I don't "think" its likely to spontaneously fail, but just something to keep I'm mind esp if there is any horse play around the set (little kids or teens that are not fully baked). For liability reasons I would hesitate to sell a set that had implosion protection that was removed by me.

rcaman
02-07-2017, 09:42 AM
I had a 25" color crt to implode on me when i was 16 or 17 it is something you will never forget. I HAD ONE SMALL SCRATCH ON MY NOSE but the explosion and mess was a memory maker ever heard a bomb go off. i have full respect for a crt. steve

Electronic M
02-07-2017, 09:58 AM
I always clean the removed safety glass spotless then caulk it to the masked off edges of the CRT face....I see that as being a period correct safety solution. Before bonding there was always a separate plate of safety glass in front of the screen mounted to the cabinet, and that was seen as a proper/sufficient safety measure at the time. When bonded safety glass came on the scene, for a few years it existed along side a non-bonded version that consisted of the same piece of glass with a rubber gasket around the perimeter that was held to the CRT face with the CRT mounting hardware. Ever compare a 21FJP22 with a 21FBP22? The way I see it converting a bonded tube to an edge caulked tube is no different than converting a 21FBP to a 21FJP, and should be just as safe as a factory original 21FJP once completed.

DaveWM
02-07-2017, 10:09 AM
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.

Electronic M
02-07-2017, 10:37 AM
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 or 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.

Electronic M
02-07-2017, 10:45 AM
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
02-07-2017, 10:46 AM
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.

.

DaveWM
02-07-2017, 10:54 AM
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
02-07-2017, 11:17 AM
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
02-07-2017, 11:26 AM
Perhaps, but I am not aware of any non bonded or non banded rectangle color tubes out there in sets as standard equipment. ...

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.

Electronic M
02-07-2017, 11:37 AM
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
02-08-2017, 05:28 PM
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
02-08-2017, 06:45 PM
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
02-08-2017, 10:38 PM
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
02-08-2017, 11:27 PM
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-Resin-/162381033494?hash=item25cea9f016:m:mZQ6TslEjpiofhA 0kF11IVA&item=162381033494&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
02-08-2017, 11:42 PM
From what I can find, cps stands for centipoise, a measure of viscosity.

Kevin Kuehn
02-09-2017, 03:03 AM
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
02-09-2017, 07:42 AM
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
02-09-2017, 09:41 AM
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
02-09-2017, 10:51 AM
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!

.

Electronic M
02-09-2017, 11:06 AM
And you could use clear silicone caulk, rather than white!

.
I do use clear...It ain't perfectly clear so I try not to let the bead get more than 1/4" in so it is never seen when installed.
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN1091.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN1091.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN1086.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN1086.jpg.html)
http://i1095.photobucket.com/albums/i469/ElectronicMemory/CRT%20cateract%20removal%20pictoral%20journal/DSCN1085.jpg (http://s1095.photobucket.com/user/ElectronicMemory/media/CRT%20cateract%20removal%20pictoral%20journal/DSCN1085.jpg.html)

WISCOJIM
02-09-2017, 11:17 AM
I do use clear...It ain't perfectly clear so I try not to let the bead get more than 1/4" in so it is never seen when installed.
Yep, I meant as a tip for Dave who had used white caulk. Even if he had gotten the caulk on better, with white you would still see it around the CRT whenever looking at the set from a sharp angle.

.

Electronic M
02-09-2017, 11:21 AM
Yep, I meant as a tip for Dave who had used white caulk. Even if he had gotten the caulk on better, with white you would still see it around the CRT whenever looking at the set from a sharp angle.

.
Gotcha. I tend to take a quote of one of my posts as a direct reply to me...

WISCOJIM
02-09-2017, 11:27 AM
Gotcha. I tend to take a quote of one of my posts as a direct reply to me...
Sorry for the confusion. I meant my response as a addition to what you had posted, not a criticism of your work, which looks great BTW.

.

DaveWM
02-09-2017, 11:35 AM
which Dave? I never use caulk. is the OP another Dave?

WISCOJIM
02-09-2017, 11:46 AM
TUD1 = TheUniversalDave1

Electronic M
02-09-2017, 11:55 AM
Sorry for the confusion. I meant my response as a addition to what you had posted, not a criticism of your work, which looks great BTW. It's cool. I know/knew ya meant well. Thanks for the compliment. That was the first-third one I did (did them all of my first 3-4 cat removals in the same ~2-4 days so I can't remember the order any more).

which Dave? I never use caulk. is the OP another Dave?
I think he's talking about TUD1, below his name it says "the universal dave".

DavGoodlin
02-09-2017, 03:44 PM
Another Dave here....I was in a hurry and used what I had which was white silicone. I will be re-doing the attachment as it did spread inward so that it was seen at the sides of the 21" round tube.

Tom has the right stuff - GE clear silicone and I just bought some, maybe because I'm working on a GE:thmbsp:

MadMan
02-09-2017, 10:17 PM
And you could use clear silicone caulk, rather than white!

https://dl.dropboxusercontent.com/u/37540750/_ponies/gilda%20this%20up.PNG

Also, guys, I was looking into fixing my cracked cellphone glass, and they use a uv-cured glue called LOCA to bond the glass to the lcd. Wouldn't it make sense to use that for this? It's not terribly expensive, it would bond the entire safety glass to the tube, be completely clear, and - I imagine - offer some implosion protection, as versus nearly none that the bead of silicone around the edge offers.

Radiotronman
02-10-2017, 07:35 AM
I agree that the clear silicone and clear double sided tape is definitely the way to go. If you do it neatly it will look just like new. Here's one I did last year.

DaveWM
02-10-2017, 07:59 AM
https://dl.dropboxusercontent.com/u/37540750/_ponies/gilda%20this%20up.PNG

Also, guys, I was looking into fixing my cracked cellphone glass, and they use a uv-cured glue called LOCA to bond the glass to the lcd. Wouldn't it make sense to use that for this? It's not terribly expensive, it would bond the entire safety glass to the tube, be completely clear, and - I imagine - offer some implosion protection, as versus nearly none that the bead of silicone around the edge offers.

I looks like the orig system was to install the glass, use tape to seal the edges and then inject the liquid thru a small plastic port. Not sure how the glass was maintained a consistent distance off the CRT face. I did a quick of a 20x20X.1 volume of 40cubed inch, about 22 oz. Not sure if its sold in bulk for that kind of delivery.

DavGoodlin
02-10-2017, 12:03 PM
I agree that the clear silicone and clear double sided tape is definitely the way to go. If you do it neatly it will look just like new. Here's one I did last year.

That CRT on the left is identical in degredation to one in my shop right now. What method(s) did you get that one off?

I have a Colorama dated 67-04 , my "chassis test jig" crt, and the bonding agent for LCD mentioned above may be perfect to maintain some integrity on a CRT not in a console.:scratch2:

Findm-Keepm
02-10-2017, 12:21 PM
I looks like the orig system was to install the glass, use tape to seal the edges and then inject the liquid thru a small plastic port. Not sure how the glass was maintained a consistent distance off the CRT face.

4 identical spacers punched from a sheet of the same resin are placed at the corners - the safety glass is lowered into position, and then caulked with RTV102, then the resin is injected.

Patent 4656522, assigned to RCA has the details.

Radiotronman
02-10-2017, 04:58 PM
I use a cardboard barrel padded with a moving blanket and sit it directly in the sun, in the summer of course. I use wood shims and a rubber mallet to tap the shims in every 15-20 minutes or so. I wait for a 90+degree day and let the sun do most of the work. I like the wood shims better because they cover a wider surface area and are gradually tapered.

edison64
02-10-2017, 07:31 PM
The PVA (adhesive) seamed to vary a lot, and I guess it's condition after all these years matters, too. I first discovered water would work when I dug out an old RCA round tube that I'd left sitting out in the woods for a number of years. The PVA had turned to jelly. I did one in a kiddie pool and it worked after 2-3 weeks, though still took some prodding. Others haven't responded nearly so well, especially the green type used by Zenith and others.

The Zenith tubes with the Green Halo or cataract will not react to water as it is not PVA polyvinyl acetate water only works on the tubes that have a white or a grey cataract I've done quite a few and if never had a problem. But as I stated the green cataracts can only be removed with a heat gun and lots of patience or a hot wire usually a guitar string hooked to an old battery charger you simply pull it through and it melts its way and boy does it stink

TUD1
02-10-2017, 08:30 PM
Just got through doing the RCA Colorama with the Zenith style halo. I used a heat gun, and about an hour and a half of my time. I had to force the wooden pieces in between the glass, and amazingly, nothing broke. I got the glass off just fine, with LOTS of heat. And yes, the green stuff smells like burning piss. I'll take the RCA style any day over the Zenith style.

Electronic M
02-10-2017, 08:50 PM
But as I stated the green cataracts can only be removed with a heat gun and lots of patience or a hot wire usually a guitar string hooked to an old battery charger you simply pull it through and it melts its way and boy does it stink
No need to run current through the guitar string or heat it....I've done cold guitar string zenith cat removals, and they work as well as hot does. Interesting that the heat gun method works, but I would still not recommend it due to the implosion hazards involved in the heat gun methods uneven heat...I've had RCA CRT faces crack from being unevenly heated by the sun so I'm a bit less of a fan of heat based cat removal methods than some.

And yes, the green stuff smells like burning piss. I'll take the RCA style any day over the Zenith style.

I've always thought it smells exactly like a brand new out of the box inflatable pool toy....Magnified by like 30X.

WISCOJIM
02-10-2017, 08:59 PM
I've always thought it smells exactly like a brand new out of the box inflatable pool toy....Magnified by like 30X.Happy memories of my youth! Every time I get a whiff of that smell it reminds me of when we went to the Sinclair station to gas up Mom's car in the 1960's. They used to give away inflatable Dinos with a fill-up.

https://images-na.ssl-images-amazon.com/images/I/51raTd6xbsL.jpg

TUD1
02-10-2017, 09:48 PM
What did you say about implosion? I took care of that prior...

MadMan
02-12-2017, 03:40 AM
I did a quick of a 20x20X.1 volume of 40cubed inch, about 22 oz. Not sure if its sold in bulk for that kind of delivery.

Huh. A fair point. 22oz = 660ish mL. It's sold in 5mL usually, 50mL would be about $30... but really, I still think it's feasible, the layer would just be very thin. But then... with no real gap, that diminishes the safety aspect, doesn't it?

idk