Have any of you ever experienced a catastrophic implosion of a picture tube in the shop? When I first started working around them in the 60's I was scared-to-death that one might implode if I looked at it cross eyed. Over the years we had several break from various causes, but fortunately never had an instance where the shop was sprayed with glass or anyone was injured.

This is scary. (http://videokarma.org/showthread.php?t=247887)

That is VERY scary!! WOW! I don't know how I missed that thread. I always considered myself lucky for not having experienced something like that. Now doubly so.

Our friend Douglas had a harrowing experience not too long ago...

Our friend Douglas had a harrowing experience not too long ago...

Yep, he describes it in the thread David linked above. Mr. Harland has been amazing and inspiring me for awhile now, so reading that even he had such a disaster definitely makes me all the more fearful/respectful of my CRT.

I had intended to carefully remove mine to apply new aquadag and clean the safety glass. Besides not holding it by the neck, handling it like a stick of leaky dynamite, resting it on several folded blankets, etc., are there any other precautions I should take to keep it from rending me to shreds?

When I was service manager at Radio Distributing, an Rca parts distributor. One of the guys dropped a 21 inch round crt in the box and shook the entire building which was about 400 feet long. Luckily it was still in the box. He was trying to move it off of a stack of crt's piled three high.

Didnt see it happen, but was there for the aftermath:

Customer had aquired his own CRT for his set. I think it was from Sears. He installed it himself. Instead of buying the correct tube, with a bonded safety glass, he went with a less-expensive tube without the safety. I still dont know how he figured out how to get a tube minus the glass.

We went to his home, and there was glass shards allover his living room, and the front of his TV was literally blown out.

He told us that when reinstalling the tube, he had a rough time getting the strap on the bell tightened enough, but finally got it, as he could tell by the rust marks on the strap screw threads. I couldn't tell him about differences in CRT sizes at this point.

The new CRT was in the set less than 24 hours before the implosion. Luckily, the customer and HIS KIDS were not watching TV when it happened, or things would have been much worse... I know the kids sat real close to the screen. I do know that the set was turned on, and the family was in the next room eating dinner.

The customer replaced his living room furniture, and all the carpeting, since even after careful cleaning, there was still glass in everything.

After all this was over, we installed a new CRT in his set... I want to say it was a GE, with the right safety glass, and I still have him for a customer today.

For a hoot, about 25 yrs ago, I bought a forlorn old 23" B/W console, took it up to the local dump & shot it w/my Uzi...A buddy taped it...Still have the tape somewhere. Kinda made a Believer outta me...

I have to remove the glass on a tube here in the near future, this time I'll be sure to wear some protective clothing. last time I just broke the lens to pieces with a FLATHEAD SCREWDRIVER. Yikes.

For a hoot, about 25 yrs ago, I bought a forlorn old 23" B/W console, took it up to the local dump & shot it w/my Uzi...A buddy taped it...Still have the tape somewhere. Kinda made a Believer outta me...

Sandy, that might have been a real collectors item!! Were you drinking or doing some of that I-420 stuff???:smoke:

I shot at a 25" color Admiral with a .22 rifle one time. It had survived a house fire, sort of. One shot went through the center of the screen. Then, it whistled really loudly until all the vacuum escaped. I've always been a believer in CRT implosion possibilities.

Bruce

Ha! Drinking and 420 make me curious about doing stupid crap as well.

Needless to say, I have intentionally imploded many crt's. But, nothing collectible, and always as safely as possible. From about 2005-2008, I must have trashpicked over 100 tv's in my area. Yes, some met a sad fate.

I'm glad that link was posted, I somehow missed it this spring. Scary stuff!

The most impressive crt implosion I've seen: when I was a teenager my favorite way to dipose of junk sets was to set them on fire. I had this GE console from about '80, typical-no signs of life, beyond my limited ability. So, I drug it outside and threw some gasoline in the back. Poof! Now, when the heat is really getting to that crt the phosphors will start to darken, and that's a good time to stand back! With this particular set, just as this happened my highschool sweetheart walked around the corner. There wasn't time to tell her what to expect....WHOOMP! Glass went everywhere, proof that the safety of a modern tension band crt has its limits.

Back in the 70s, when I was in college, I had to dispose of a 20 or so inch B&W CRT in the TV cabinet. The town trash collectors wanted us to let the vacuum out of CRTs by breaking off the little evac seal at the socket. We put it at the curb. Well, this CRT had a bakelite base and the glass seal was not accessible. So I decided to stand back about 25 feet and toss rocks at the CRT neck to snap it off, and be at a safe distance. I missed the neck, but nailed the big part (like where the high voltage connects to). Kaboom! flying glass all over the street and front yard lawn. Good thing I was 25 feet away. I wonder if the CRT phosphors helped fertilize the grass any. Don't remember any brown grass afterwards.

My CTC-24 has a minor cataract, and it's gonna stay that way. I've only removed the safety glass from one set, a CTC-17, and that was because the safety glass was broken and it had a bad cataract which was easily taken care of.

This is an interesting thread! FWIW I will add my 2 cents worth.

WRT the implosions that occured during the removal of the bonded safety glass in an attempt to remove the cataracts. It is very likely that the implosions were caused not by anything physical. It is most likely that the tubes imploded due to the UNEVEN application of heat and cooling. The glass envelopes from shich tubes are constructed, are under a lot of stress from the vacuum inside them. Imagind 14.7 PSI pushing inward on every single square inch of the tubes envelope. We are talking about many many tons of force.

Glass is a very britle material. apply heat to only one area of the tube and you will cause the glass to expand enough that the huge forces on the tube due to atmospheric presssure, are enough to cause the envelope to crack. IF the tube was not vacuum, the envelope might not even crack, but due to the forces on the outside of the tube from the pressure of atmospheric pressure, you are asking for big trouble if you heat the tube unevenly.

Another point. Several years ago somebody posted about a 21fjp22 he had sitting in his garage for some years. Often the tube was sitting with the fase of the tube submerged in water. When he went to move the tube, the safety glass just fell off.

On my lst trip to Hawkeye I asked Scotty about his method of safety glass removal. He said that they placed the tubes in the warming oven. (presumably after the vacuum relieved and the gun was removed. Then whent he tube was warm, they would pop off the safety glass.

Scotty said in the old days, they had a tank which contained water and detergent, and they would place the safety glasses that had been removed into the tank and let them soak for a week. The soaking softened the bonding agent and made for easy cleaning.

From all of the above one might reasonabley expect that it is not necessary to remove the safety glass using heat, provided you are in no hurry. I suspect that simply soaking the front of the tube in soapy water for a long period of time will cause the safety glass to loosen and the PVA to soften so you can remove it easily.

I have a number of color crt's with bonded safety glass. I am going to experiment to see if the safety glass can be removed by just soaking in soapy water for a long time. I will let the group know the results. This may take a month or more so don't hold your breath.

As a novice to this forum when I read the cataracts thread I foolishly :o argued that they wouldn't have used PVA to bond the safety glass because PVA is water soluble which would cause problems.

Since they really did use PVA the water bath removal makes sense.

If you dig through the old threads you will read my experience with water. It was positive. I tried it with the "green" type used by Zenith and others, the one that does not respond well to heat. I bought a cheap blow-up kiddie pool at the dollar store and let the crt sit face down in water. It took about 5 days, as I recall. I think the longer you wait the easier it will go. I tried it later with the RCA style PVA and it didn't respond at all even after a week. If you have an outbuilding with some spare room, I say just get such a pool and let it soak. Detergent couldn't hurt. Some have suggested kerosene or other solvents-the trouble I see there is that you then have to deal with this vat of flammable, smelly stuff. There is a product called Bean-a-Doo which is sold as a soaking agent to remove adhesives from automotive trim, and perhaps it would work. Made from soybean oil. But, very expensive. Even plain vegatable oil would be expensive if you bought enough to soak a tube.

I have removed several faceplates with heat, with good results, but I am nervous after reading some of these experiences. I may be removing one this week but I don't think that one has any adhesion left at all. I may stick with water from here on out.

Have any of you ever experienced a catastrophic implosion of a picture tube in the shop? When I first started working around them in the 60's I was scared-to-death that one might implode if I looked at it cross eyed. Over the years we had several break from various causes, but fortunately never had an instance where the shop was sprayed with glass or anyone was injured.

I've posted this before, but here it is again:
My only "serious" experience occurred the summer when I was 17. I was helping my Dad swap CRTs (25AXP22's) between two sets at his TV shop. I pulled the bad CRT out of the set and set it on the dump pile outside, then busted the "tit" to let it go to air, no problem. Dad, meanwhile, left to go get a new blue lateral assembly at the parts place a mile away. I was alone and with the vigor of youth, decided to pull the "good" tube to have it ready when Dad got back. I unbolted it just fine, and I lifted it from the set (by the neck) and set it on the edge of the cabinet to reposition it. I then hoisted it up by the sides (face down), only to have the 2nd anode button come in contact with my abdomen and now-sweaty t-shirt. WHAM!! - I got the residual charge. I reacted by pushing it away from me, into the corner of a workbench, imploding the CRT about 6-8" from me. I was shaking, and alone, and uninjured. My only scare was what was I going to tell Dad when he returned. Thankfully, he laughed it off after ensuring I wasn't hurt. Glass shards were everywhere, and we even found some 6 months later when we moved some equipment around in the shop.

Cheers,

...Made from soybean oil. But, very expensive...

Have you considered trying biodiesel? B100 should cost around $3.50 a gallon, and is not that flammable or smelly. It dissolves rubber fuel lines, it might work well on this. The only trouble would be finding it as very few fuel stations sell 100% biodiesel, moreso this time of year.

-J

Have you considered trying biodiesel? B100 should cost around $3.50 a gallon, .... It dissolves rubber fuel lines, it might work well on this. ...

Well, there's brake fluid, which is widely known to dissolve paint. maybe it would do a CRT. My brother uses brake fluid to remove the paint off of his plastic model train models.

If the bonding material on a particular tube is a type of polyester resin (I believe that some were ... PPG 5252 or something like that), methylene chloride will do the job. Very nasty, however. :yuck:

jr

If the bonding material on a particular tube is a type of polyester resin (I believe that some were ... PPG 5252 or something like that), methylene chloride will do the job. Very nasty, however. :yuck:

jr

Dow Chemical's formula is in Patent 3007833:

33 parts by weight diglycidyl etherr of bisphenol A, 67 parts diglycidyl ether of polyoxypropylene glycol having a molecular weight of 400 and 5.5 parts of monoethanolamine and 1 part of diethylenetriamine.

What that means, I dunno. The patent is for the use of a Saran wrap band around the tube and safety plate while filling the gap with the above mix.

US Patent 3265234 from Union Carbide lists a number of other chemicals that were used to bond the safety plates - about 4 or 5 formulations are compared.

I guess not all CRT's used the same bonding materials....


Cheers,

I guess not all CRT's used the same bonding materials....


YES! I think that is the reason for some frustration on this board... methods for dealing with one type of bonding material may not be effective, and perhaps even dangerous to use to remove another type.
Dow Corning 184 for example, was sometimes used on smaller special purpose tubes where high optical quality was desired... I suspect that heat alone would not be effective to remove a faceplate bonded with 184.
jr

If the bonding material on a particular tube is a type of polyester resin (I believe that some were ... PPG 5252 or something like that), methylene chloride will do the job. Very nasty, however. :yuck:

jr

Really nasty and dangerous. It has a high vapor pressure and will evaporate very quickly. It would have to be a very valuable tube before I'd try it.

YES! I think that is the reason for some frustration on this board... methods for dealing with one type of bonding material may not be effective, and perhaps even dangerous to use to remove another type.
Dow Corning 184 for example, was sometimes used on smaller special purpose tubes where high optical quality was desired... I suspect that heat alone would not be effective to remove a faceplate bonded with 184.
jr

I'm not sure how you'd do that either. I still have a scar from trying to remove a PMT from a light guide that we wanted to save that had been bonded with Dow 184. Have you ever seen a cataract or similar form with 184? I'd expect it to last nearly forever. Rebuilding a CRT bonded with it would be a real bear. A long term soak in trichloroethylene would swell the 184 and loosen the bond, but is also hazardous.

Dow 184 is nearly ideal for the purpose, but would break the bank for a large CRT.

Have you ever seen a cataract or similar form with 184? I'd expect it to last nearly forever.

Yes, I have observed partial de-lamination on some tubes using 184.... sort of looked like "worm tracks" in the material.

Dow 184 is nearly ideal for the purpose, but would break the bank for a large CRT.

I see that Amazon has the material listed, wonder how many 21" crts could be bonded with an 3.9kg "kit" for $336 ?:eek:

jr

Yes, I have observed partial de-lamination on some tubes using 184.... sort of looked like "worm tracks" in the material.



I see that Amazon has the material listed, wonder how many 21" crts could be bonded with an 3.9kg "kit" for $336 ?:eek:

jr

Guess it would depend on the bond line. If it was 1/8" you could do about five 21" CRTs.

John

Used to put old CRTs in a 55 gal trash barrel & chuck a rock in from about 20' away. Always got an impressive geyser of glass out of the barrel.

My Dad owned a TV shop ,we wrapped a furniture moving blanket around the tube: Then , put it in a METAL trashed can and then broke the neck off with a LONG pipe.
Now working at NASA with huge vacuum chambers on night-shift..............
Put it this way........... I don't fall asleep at work !!!
I'm always ready for the unexpected !!!!!!!!!!!!!!!!!:scratch2::smoke::nono:

If the bonding material on a particular tube is a type of polyester resin (I believe that some were ... PPG 5252 or something like that), methylene chloride will do the job. Very nasty, however.

jr
Really nasty and dangerous. It has a high vapor pressure and will evaporate very quickly.

And the neighbors might think that you have set up a meth lab... :D

Working in a tube rebuilding facility in the '60's, the only time we had a tube implode was in the ovens. Years ago, I had a TV repair shop in our local flea market where I would repair TV's while you wait. There was another guy who started up on the other side of the market which we called "Brand X". A good guy but more of a piddler. One day I heard a tube go off (I knew that sound!) and ran to the other side of the market where he was sitting down on the floor in bewilderment beside the TV. I was for sure at that point that he was seriously hurt as there were chunks of glass shards all over the place and a few customers running. What he had done was cut the pressure band off of a live 25" tube to make it fit into the cabinet. DON'T YOU EVER CUT A PRESSURE BAND OFF OF A LIVE TUBE!!! EVER!!!

The theory is before a tube can implode, the faceplate has to be forced inward and it cannot if there is a band on the tube. For rebuilding, we took the band off after the tube was let down to atmosphere pressure.

that story reminds me of my post about "hillbilly frank".he cut the band of a magnavox crt to use in something else.he fired the set up and after a few minutes,i heard a blast like a grenade.the set exploded in his living room.he was on the phone with me when it happened.i have cut off the ears on a magnavox crt but never cut the pressure band.though it didnt pull the nails from the walls,it did leave pieces everywhere.

Why was the band cut off during rebuilding-heat expansion issues?

Yes, when the tube goes into the over the band has to come off because it has to expand or it definitely will go off in the oven.

nver understood how the band prevented implosion, thats for that explantion.

so I guess the follow up question would be, if a bonded glass CRT has the cataract removed, then why would the CRT not implode upon removal of the bonded glass? Can a band be added to a tube that had the bonded glass (guess before the removal takes place) to be safe again? if so is there a procedure/tools/tension mearuring device that should be used?

Because the glass is just glued to the front of the CRT, it does not impart any tension on the face at all like a band does.

besides the band or safty glass is there a difference in the contsrution of the two?

What I am getting at is "should" a band be added to a CRT that has the safty glass removed.

If they are the same basic CRT just one uses bonded glass and the other has a band, then it would seem that a band should be added if the bonded glass is removed.

besides the band or safty glass is there a difference in the contsrution of the two?

What I am getting at is "should" a band be added to a CRT that has the safty glass removed.

If they are the same basic CRT just one uses bonded glass and the other has a band, then it would seem that a band should be added if the bonded glass is removed.

As far as I know, they would NOT be "the same basic CRT," as I don't think you will find the same part number with a safety glass OR a band - it will be one or the other. Note the danger of implosion of a banded tube when the band is removed. This tells me the banded and unbanded tubes must be basically different. The engineers may have determined that a particular glass kit could be used either way, but I don't know if that has ever been done, unless someone who knows tells us.

when i was about 11 years old me and some of my friends were playing around in a house that had burnt down months before we went in it..
the roof had collapsed in several of the rooms. and there was a large tv in the living room. the case was real wood and i remember the screen looking grey and not black like moden screens..
the tv was atleast 32inches..

we were throwing rocks at it trying to break it.. after all we were kids and the tv was glass...
i was throwing big rocks or chunks of cement at it.. it was only scratching the screen..
my friend threw a small rock at the screen and BOOOOOMMMMM!!!
it was a amazing sound.. it felt like sombody hit me in the chest.
i actually moved alittle from the sound it made..
it was louder than the artilary shell fireworks..

it was definetly something i didnt expect to happen.

A couple of scary implosions on YT...

http://www.youtube.com/watch?v=NnZ39EL-wF0

http://www.youtube.com/watch?v=zKvyGt7xhGw

the 2nd one definetly shows how deep and loud the boom can be.. sombody needs to do it with a really good microphone..
when i did it.. it felt like sombody hit me in the chest.

Here's a video of someone smashing the 40" screen of a Sony Trinitron with a sledgehammer:
http://www.youtube.com/watch?v=XNojx-r1TY8

:no:

well atleast he took safety into account.
although he should of have worn gloves also.

I was sorta hoping for the shrieks of agony to commence...

http://www.youtube.com/watch?v=cnLWXFFZ5Ss&feature=related

Whew, just got done breaking the lens off an FJP- back is killing me. Thankfully I did NOT have an implosion experience. lol

Here's a edited fake video of a guy smashing his TV screen with a hammer and gets blown to the back of the room:
http://www.youtube.com/watch?v=5G0kA845GgM&NR=1

I have intentionally imploded many CRTs but i also had one implode accidentally on me.

It was a mid 60s 23" B/W tabletop set with a bonded lens CRT i had when i was a kid, it was an European style set with a push-through screen so it was very front heavy, it toppled off my outdoor bench while i was unscrewing the back panel to fix it.
The shockwave was so loud it roared all over the neighborhood and scared the crap out of my parents.

Luckily the back panel was still on and the bonded safety lens did its job so the implosion remained 100% confined inside the set.
The set's speaker was totally shredded by the implosion!

I just got back from my folk's house, where I soaked an FJP in methylene chloride for a day in an attempt to melt the PVA out. Yeah, didn't even budge. I ended up breaking the safety glass off, just like the last one.

Im going to try the water trick. I have plenty of crts around here that need the glass removed. I just need to find a container and will let it soak for a month or so.
Its the RCA style that freaks me out. The Zenith green style cut off so easy with a hot wire I dont worry about those exploding.

Yeah, for that one that imploded on me, we gathered up the PVA and I tested some common solvents to see how it would react. I forget what all I used, a short list would include: MEK, denatured alcohol, carb cleaner, brake cleaner. I sat the pva chunks in some sealed containers with the stuff for a week, and NONE of them really changed after that punishment. This was an RCA tube, btw.

Some real life experiences/observations regarding this topic.

In another thread there was a short discussion regarding PVA vs PVB and a comment was made that auto glass uses PVB and that it doesn't suffer cataracts. Well I've run a car restoration shop and cataracts are actually fairly common, especially on vent windows (remember those?) and flat side glass. Have even seen them creep from the edges of some windshields.

Speaking of auto glass...had a first generation Mazda RX-7 that lost one of the spade connectors for the printed circuit defroster on the rear window (which was a hatchback). Removed the window and sat it upside down on some blankets. Using a soldering iron I was able to solder a replacement connector and left it to cool. Maybe 10-15 minutes later glass was raining down after the damn thing exploded. The interesting thing is that this was bonded safety glass AND had a metal frame around it...add to the equation that unlike a CRT there was no vacuum to contend with and I'm now even more ascared of working on picture tubes. Obviously I induced an incredible amount of localized stress. Mazdas may make you go "Hmmm" but in this case I went "WHATTHEHELLJUSTHAPPNED?!"

Regarding whether rebonding the safety glass is stronger (or not) then just sealing it around the periphery I vote that the original full face bond is stronger. Just stands to reason that the bond effectively doubles the thickness of the individual glass layers, plus it probably adds shear strength as well. Think of where plywood gets it strength from, layers of opposing grains of wood PLUS glue in between.

I could be completely wrong but that's my take on it.

"should" a band be added to a CRT that has the safty glass removed.

.

The band was just for the mounting lugs ?

The band was just for the mounting lugs ?

Anybody correct me if I'm wrong here but yes, basically it's there for the mounting lugs to easily facilitate installation/replacement. Most tubes as we know had some sort of strapping set-up that mounted the tube to the bezel. There is the exception of some early Zenith Rectangular tubes that mounted in a "surround" then that was then bolted in, and was a PIA to unseat from the old tube during replacement.

Has anybody noticed any cateract conditions with the band/lug type tubes? With all that strapping and shielding was the use of bonding materials eliminated?

As for releasing tubes of vacuum, I remember a safe way was to drill a hole in the anode button after making sure it would remain discharged!

---

I think one way to reduce the chance of an implosion during a faceplate removal is to get the whole CRT as warm as possible before using the heat gun. The one time (so far) that I removed one, I put the CRT in the sun in my back yard for a few hours before starting the removal. It was quite hot, but since I was already wearing gloves for safety, I could pick it up and move it easily.

Okay, folks, here is another one to add to our "collective experience".

Another VK member needed the safety glass off of a 21FJP22. Since I had a couple dud tubes in the attic I decided to pull one off. The crt in question is a used Philco-built tube that was gassy, from all I could tell. Certainly beyond anything a rejuvanator could do. I took it took work and let it sit in the shop for a few days before deciding to work on it today. I started warming it up with the heat gun-I've done 4 or 5 of these before using this method but after reading a couple implosion stories, I found myself unerved this time. I decided it really made more sense to air down this tube. I used my usual method for tubes I'm going to junk-I used an awl to poke a small hole in the ultor. No drama, it went to air in a minute like they usually do. I then flipped the tube back over. I decided instead of using the heat gun I would use a bank of infared lights I have at work. After setting them up it took some time before I started seeing results, maybe 45 minutes or so. I rotated it 30 degrees or so every time I walked by. At one point I looked and saw cracks, which made me think the safety glass had broken, but on further inspection I saw it to be the PVA. It was not until later, when the glass loosened enough to pull off, that I realized that, in fact, the face of the crt had cracked! (see photos) I can only assume this would have also happened had I not aired the tube, in which case I would have woke everybody in the shop up!

Lesson for me: from now on, it will be water only. I just don't trust heat anymore.

I agree, water only, These round tubes are to scarce at this point to risk it. Leave it or soak it.

I still feel good about wire slicing the green halo zenith style ones though.

PVA is soluble in a number of organic solvents. Solubility of PVA is directly related to the volatility of the solvent; the more volatile the solvent, the more soluble the PVA. Some of the most common solvents, ranked in order from the most volatile to the least, are listed below.



1. diethyl ether (very volatile, water miscible) 2. acetone (best solvent that is commonly used) 3. benzene (very toxic) 4. ethylene dichloride (very toxic, non-water miscible) 5. methanol (toxic, cumulative poison) 6. methyl ethyl ketone (MEK) (toxic) 7. ethanol (denatured alcohols may be toxic) 8. toluene (slightly toxic) 9. xylene (slightly toxic) 10. amyl acetate (slightly water miscible).


This site indicates that PVB should be soluable in Toluene or Ethanol
http://www.ferro.com/NR/rdonlyres/0A2860C5-2208-45A7-8548-C185933173E1/0/B75702.pdf

Destroying a tube only to get the faceplate. I cannot express how poor a judgement for a rare tube that can be rebuilt in the future when equipment is available again. If you are afraid, then leave it alone!!! Circuits in the set can be made or modified to make it work again but a tube cannot be made up.

Like sending an antique car to the shredder to save the windshield.

It's not like we'll be able to get them rebuilt any time soon, I have 3 duds that will be sitting for who knows how long? Who cares about 1 roundie tube, more then we know get thrown away every day. It's not like he wrecked a good 21AX or something.

I've asked opinions about these duds more than once. I had also sent a PM to somebody involved in the ETF rebuilding process, without response. Believe me, I am a total packrat and do not toss anything until I am sure it is junk. In this case, I just could not justify holding on to this dud. Here is one reason: why would you need a crt? One of two reasons, either the old tube is worn out, or it is busted. But if you have a worn-out 21" roundie tube, why not just get it rebuilt, instead of using a dud like this one? Anyway, the faceplate will end up on a good crt which could not otherwise be safely used without it. Aside from that tube I have another dud 21FJP22, a good used 21FBP22 and a good used 21" test jig tube with "Test Tube" acid etched into the face. I also have 6 color roundies, all with good picture tubes, and some others could be heading my way. I don't know that I have $200 invested in the whole pile of sets and tubes altogether. So, no, I'm not really going to lose sleep over this one tube. And, no, I wouldn't have touched a 21AX.

You don't have to explain yourself Bryan. I'm just glad your 6th sense kicked in and you didn't become another implosion horror story...or a statistic. :worried:

Bryan- You made a sacrifice and chose your worst tube. Since it was gassy, there would also be the chance that it was going to air. And it would have been a poorer candidate for rebuilding if and when we may ever see that occur. I am a preservationist at heart but you chose wisely, Grasshopper!

You have also provided a valuable lesson to us by sharing what can happen even to a tube that is at atmosphere. As I have mentioned elsewhere I have a Zenith labled RCA coded 21FJ that has the dreaded PVA cateract and the heat method while having been successful (at times) is no doubt stressful on a tube under vacuum and a little more dangerous than I like. This has been a good thread!

On another note, except for the point of originality I wonder if it's really necessary to reinstall the safety glass face. Even though I'd prefer it, I do have a local jobber (in the day) rebuilt 21FJ that was supplied without the safety glass face, back in the early eighties that I purchased. Some rebuilders seemed to have stood behind that decision as well as claiming how much better the picture would look. Granted, the sharpness, contrast as well as the color look outstanding. The tube is in its second installation.

And think of it this way, a 21FJ without its safety glass is pretty much the same as a 21FB. How many times have we handled these tubes as well as older black and white types and have them in various places of storage and have not have not had any issues of them imploding on their own? We seem to understand that the safety glass front does not affect the structual integrity of the tube. However rare, other than from mis-handling or mis-use or an accidental situation does it seem that there will be an implosion.

...

I would bet those rebuilt tubes that lacked their safety glass had a tension band installed.

Not that I've seen, Wayne's CTC-5 has a Hawkeye tube in it and there's no band. I seriously doubt the safety glass had anything to do with stress on the tube itself, just look at the way they are attached: they laid the lens on the front of the tube, then injected PVA into it as a bonding agent. I have 2 FJP's with removed lenses in my sets, and they are doing just fine.

...

What tension band? None of the tubes I have had anything like that, except for the square ones. Are you sure you aren't mistaking mounting hardware for a tension band?

I hope Hawkeye wasn't sending back rebuilt 21FJP22s with missing safety glass and no tension band unless they customer asked him to turn it into a 21FBP22

When I talked with Scotty, he told me he can't rebuild the tubes without the glass being removed anyway. Wayne's tube has no band, but I'm pretty sure it has flat glass.

I never said the bonded safety glass had anything to do with preventing stress on the CRT. All it does is provide a layer of protection for the CRT (in case something strikes, or scratches the screen), and it helps contain the flying glass if it does implode for some reason. I hope Hawkeye wasn't sending back rebuilt 21FJP22s with missing safety glass and no tension band unless they customer asked him to turn it into a 21FBP22.

Using a CRT with the bonded safety glass removed is fine as long as there is a separate safety glass installed (either flat like 50's sets, or curved like most 21FBP22 sets). Using a CRT with no implosion protection is dangerous and should be avoided.

There's a reason every TV ever made (over about 5") has either had a safety glass, or tension band. Using a TV with no implosion protection is like driving without a seat belt. Everything is fine until something bad happens. Unfortunately, you never know when or where a disaster will happen.

AFAIK no roundies had implosion (tension) bands. Any banding, I think, was for mounting only, and not for pre-compressing the faceplate, which is what the true implosion band does. So, impact protection was supplied a separate flat glass or later in some tubes by the bonded faceplate

My rebuilt 21FJP22 from Scotty definitely does not include a bonded faceplate, but it is behind the flat glass on the CTC-5, so it's protected just as much as a 21AXP22 (metal) or more relevant, the same as a 21CYP22 (glass) that was used as a later replacement.

I would bet those rebuilt tubes that lacked their safety glass had a tension band installed.

Absolutely not! The tube has to be designed to take a tension band. Ohterwise, applying one is as likely to cause implosion as prevent it.

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It wasn't on him to remove the glass, it was on you. That means he only ever has the tube in his possession, you would keep the glass. Not that it matters anymore though. :tears:

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In my case, I didn't supply the dud - just bought the restored tube from Scotty. This replaced the aired 21AXP22 that we gambled on trying (wasn't destroyed or anything, but turned out to be leaky with air evident within a few days).

Interesting, I always assumed the rebuilder handled removing, and reinstalling a bonded safety glass. I'm sure that was the case back when CRT rebuilding was common.

For the most part this is/was correct.

In fact I just asked Scotty about this and he said that removal of the glass was something he did as part of the rebuild process.

John

Maybe he told me no, because he was getting close to his shut down day and didn't want to deal with it.

You old timers have been there. Turn on the set with the unbonded tube (after CRT replacement) and you find out your Windex job on the face and safety glass was for naught and you got to do it allllll over again. Always got me going. I was never so happy as when we got bonded tubes regardless of the dud.

I was at a car show of all things, when I ran into a guy who said he worked on the CRT line at RCA Lancaster. He said that occasionally, a tube would let go when it was coming down the line (they hung on overhead hooks) and it would cause several in a row to go off, raining glass down on everyone.

He also mentioned that anyone assigned to packing crts had to wear a flak jacket arrangement. Of course, most people didn't so he said all too often, he would hear the implosion, and grab a mop so he could clean up the massive blood trail leading to the infirmary.

Back in the day when there were four repair shops on the same street, I was visiting a shop. John had just finished installing a new crt in a electrohome tv. John turned the set on to start the adjustment proceedure. We heard a tic tic tic sound. john unpugged the tv and without thinking reached in to re attach the ground strap. the next thing i saw was a hand moving faster than a Bruce Lee kung fu move and with it was the deflection yoke.The next thing i heard was a one word responce (F**K).

Well when i was a kid i used to go to the city dump with a couple friends , they would be hunting bicycle parts - i would pull tubes from the tv sets there , one day a 23 or 25 inch color set was siting there and i told a friend about the dangers , he wasn't convinced , so i stood 10 feet or so from the set and tossed a big rock dead center into the face and what a boom that was , a piece of glass landed at my feet and he was a believer , so another 25" set was picked on , i tossed the rock and it hit but the crt did not go off , multiple cracks were made in the front and a huge hiss and whine came from the set , this went on and on and as it did you could hear what sounded like things colappsing inside the crt but it did not implode.... i took a 16" sharp set to pieces and had the crt , took it to a friends house and we went to the attic 3 floors up, he dropped it and BOOM but there was a spark of electric with it , i said wow that picture tube was still holding energy .... one more - i put a 21" color table model admiral out for garbage - the crt was weak and the fly was bad , had i known i could have hunted a fly down who knows what would have happened to the set , i didn't think of it at the time and when they loaded it into the truck a minute later i heard a huge boom and then thought geez i didn't air that tube .. too bad i didn't just store the set because i might have been able to save it now.

Mike

All these horror stories! Seems the only safe place to work on or watch a CRT set is in outer space! (or the vacuum inside my head)

When I worked at a TV shop in the late 70’s early 80’s rebuilding trade-ins was a large part of my job. Once a month the garbage man would reserve some room for us to dispose of dud CRTs. I would snap the neck with a large wrench before removing the tubes from there cabinets. One day as my partner and I were sliding the tubes into the garbage truck I shouted “LIVE ONE”. My partner and I pulled the garbage truck driver to ground. KaBlaam! That live FJP took out three other tubes when it landed in the bottom of the truck. The truck driver looked like a deer in the headlights when we all stood up. The guy had no idea of the implosive power of a CRT. Doogie

Figured I'd share this the next time this thread resurfaced: the other day I was moving some things around and needed to set a 21" roundie crt somewhere. I took a folded-up towel and put it on my desk, then placed the crt face down on the towel. I then left the room for several hours.

When I came back I couldn't believe my eyes: the crt was sitting, pretty as you please, face down on the floor. There was just the slightest "tilt" to that towel-I never could have guessed it, but the crt apparently started to slide and then-plop-down it went! It survived the impact, looks like no harm done. But that was a close one. Sometimes I wonder if I should be allowed to handle anything more fragile than an anvil!

Oh-one more thing. In an old thread, somebody mentioned that they used to remove faceplates by dropping the crt facedown from a pretty good distance, and the shock (I guess) would cause it to loosen. There was some debate at the time as to whether this was tongue in cheek, but the poster seemed sincere. Well, not long ago I was preparing to junk a dud bw tube with a bonded faceplate. It did not have cataracts. After airing it, I decided to do a test. I dropped it on the ground numerous times, and then started tossing the crt as high in the air as I could so that it would hit facedown. Nope, all that bottle did was bounce all over the yard, never loosened anything, didn't break, either!

As a kid, I accidentally dropped a 10lb dumbbell on a 12lp4 that was sitting on the floor. I looked like Quint from Jaws when he thought the oxygen tanks were going to blow! Amazingly, the weight struck the neck full force, but all it did was crack the base. I still have the tube as a spare, and it still tested as new a few months ago...

I have worked in a CRT plant for 38 years and we have never had a worse injury from an implosion than a cut that required a few stitches.

I have worked in a CRT plant for 38 years and we have never had a worse injury from an implosion than a cut that required a few stitches.

Would that be Clinton???

I recently disposed of some BPC sets that were broken and I didn't want to deal with.
1 was a 20" Sony VCR combo set. I threw it in the dumpster, and man... heard a big boom when it hit the bottom. I looked in and the CRT had imploded and it blew the back right off the set!

Here are some implosions that were done for fun:

First implosion with a bonded glass Trinitron, if it had a safety band, it was removed:
http://youtu.be/cuPDWUK7pMA

Second Implosion with a Flat Trinitron with a removed band:
http://www.youtube.com/watch?v=2x6J3KJ2Uso

Third Implosion with a Toshiba CRT with a removed band:
http://youtu.be/5T6NqiHZ-Vk

had one of those 19" rca table sets with a weak but recently replaced crt.
green was gone and it arced in the neck.being a few month old rebuild i figured it was a leaker.tore it down to replace it.when i unbolted the mounts i heard a crunch.then a tink.
i stepped aside and BOOOOMM!!
nothing left in the case but the face,shadowmask,and band.
it made dents in the metal case.glass stuck in the ceiling and broke the bulbs in the shoplight above.

I scored a Philco 19" BW, 1961 vintage, found at curb. Nice shape and it had a nice raster and needed the usual paper cap replacement. As it sat on a stool operating with the back off, but I noticed the grounding spring arcing where it contacted the CRT aquadag, I left the room for just a minute and heard a boom. Lucky, but what a huge mess to clean up...

My implosion experiences are in two categories, accidental and intentional.
I ‘ve only seen one accidental implosion. When I was about six or seven, one of my grandmother’s neighbors had a house fire. And, the portable TV on a rollaway stand came rolling out of the house and onto the sidewalk. (With the help of the firemen…) The TV was on fire! And, less than a minute after hitting the sidewalk, the CRT sort of “collapsed”. And, when it did, you could see flames inside the TV set!

Years later, when I was in high school, the electronics teacher was anxious to get rid of several years accumulation of old and obsolete CRT’s –no doubt very valuable today! In that era, growing up in countryside being turned into suburbs, there were numerous places where we took CRT’s after school. A favorite area was a nearby abandoned gravel quarry whwer we’d go after school. (Yes, there were guys who had rifles in the trunks of their cars in our school parking lot! But, this was a different time. We used the weapons on old cars, old CRT’s, etc. –not each other!) Many an old CRT met its fate face down in that quarry with its neck the target of a .22 LR bullet. We had one guy who had no fear at all of what a CRT could do. He sat an old CRT face down in a dumpster, slipped a pipe collar with a piece of wire on it and pulled really hard! The neck snapped at the bulb and all that happened was a slow escape of phosporus. Said rocket scientist then took an old CRT and placed it in the dumpster. The then threw another CRT at it! The resulting double implosion was quite spectacular!

While shooting the neck off an octal base tube at 50’ feet or so was fun, when my grandfather had the opportunity (with a set from one of my cousins), he “did the deed” with the miniature base of a more “modern” CRT. He wasn’t impressed with the “whooosh” it made. He just muttered, “they just don’t make ‘em like they used to!”

The scariest NON-implosion story I have is this: In 1980, my brother and I had bought a big inventory of tubes (not CRTs) from a surplus store that closed down in Chicago, and we were offering various early radio tubes for maybe $3 each in local ads. So, we made a few radio and TV collector friends. One time a couple of them came to our house for a few tubes, and they were driving an old Suburban (with no back seat installed), and the entire area behind the (front) seat was PILED with loose CRTs! I mean, not a layer face down but at least two, maybe three layers of them at all angles, mostly probably 21-inch B&W ones. I just shuddered to think of what would have happened if they had hit a bump on the road or had had to hit the brakes hard.

A friend of mine was telling me he knew someone years ago(probably 1960's) was walking through a TV store/shop and hit the neck of a CRT of a running set accidentally with a briefcase. Of course the CRT imploded and shot the neck through the front of the set hitting a set sitting across the isle. Must of made a heck of a noise/smoke/arcing! What a mess!

Like Kojak said "I don't buy it". Sounds like an urban myth or whatever it's called. Breaking the TV's back cover, the neck, having what's left of the thin glass neck and guns shoot forward with enough remaining force to go through the front of the CRT then through the safety glass?? I don't think so.

I have to say it sounds improbable also, breaking the neck sure, but not the rest of it! :no:

If he had a Briefcase he was probably a Salesman, there's nothing a Salesman likes better than a tall tale! :yes:

it could have happened like that but probably didnt.i resent the salesman comment.when has a salesman ever told a story that wasnt true?wink,wink!this forum biased against members of the sales industry.an outrage!wink,wink

Closest I ever got to an imploding TV was the time some friends and I took turns throwing rocks at a small 13" RCA I found in the dumpster. Nothing spectacular, the glass was slowly cracked and the vacuum let out.

However I found this video on youtube. Fast fwd to the 1:05 mark. They heave a brick at it and break the safety glass, then they heave another brick and implode the tube....the glass flies at least 2 ft. from the set. Beats anything I ever saw when it comes to an imploding CRT.

http://www.youtube.com/watch?v=cHRxcdmAfBU&list=FLTqGtqMJCmjs6cyJFIXdIew&index=1&feature=plpp_video

Hey it was a story some old guy told me. Probably has some small amount of truth in it but the story seems to change little by little over the years.