#16
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I've tried several things: acetone, methyl alcohol, grain alcohol, stripper, spirits....
Nothing touches it, nothing. I always resort to chipping the lens off with a screwdriver, since I use tubes in sets with flat glass anyway.
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Evolution... |
#17
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In light of that I'd suspect there are numerous additives they put in it to get it to bond to the glass; those additives must be what solublizes in the water and also keeps things from easily eating away at the PVA.
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#18
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I can def see the little stress fingers around the edges where the toothpics are. Just have to be careful handling it with all the water making for slippery handling...
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#19
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I wonder if there are any chemists on VK or ARF that would be willing to research the possibility of designing a coumpound to disolve PVA in a comparable amount of time to the risky heat method?
Tom C. |
#20
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Trouble is anything that's going to work well is also going to be very nasty, and leaving something like that open is a no-no.
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Evolution... |
Audiokarma |
#21
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Agreed. I'd further suspect that trying to dissolve the PVA will leave you with a nice gummy mess on your tube and safety glass... If we can find out the bonding agent that is affected by the water, it may be possible to do better. I wonder if it would make a difference to gently heat the water to say, 40/50 degrees C. Not too stressful for the tube, and if done slowly, it allows a thermal gradient to establish with minimal stress.
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#22
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Zenith comes close with their patent for reducing thermal gradients during CRT "salvage"
How about Acetic acid for a solvent? PVA glue (Titebond wood glue) reacts to the stuff....someone with salvaged PVA could possibly test the theory. Cheers,
__________________
Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! Last edited by Findm-Keepm; 09-07-2015 at 01:05 PM. |
#23
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Seems like if you used a solvent it would result in a gooey toxic mess to clean up. Thats how the Zenith green halo ones are, its like jello that smells like a combination of sewage and used crankcase oil.
I avoid the Zenith ones now because cleanup is so time consuming. Yea you can cut the window off in 20 seconds with a piano wire, but then spend a week trying to get that goo off. I have a piece of pva, ill try some solvents when I get time but still think I would prefer water. |
#24
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So, stick the tube in a vat of vinegar?
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Evolution... |
#25
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If it was pure PVA, then vinegar might work... see here:
http://www.ehow.com/how_5650421_dissolve-wood-glue.html Worth a shot, I guess. Edit: Glacial acetic acid would be more potent... but harder to get a hold of. You could probably make some by distilling or concentrating vinegar, depending on the acetic acid boiling point. |
Audiokarma |
#26
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dumped in 1/2 gal of vinegar...
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#27
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DO NOT dump glacial acetic acid into a pool like that (if you happen across some). If the smell doesn't blow you away (it can damage the lungs) it will likely dissolve the pool. A half gallon of vinegar probably won't do much of anything, but hey, it can't hurt, and it's cheap enough.
I remember seeing a posting with pictures of this kiddie pool submersion method, and they stuck popsicle sticks into the edges of the pva as it worked loose. It did a great deal to speed up the process. |
#28
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Quote:
Phil Nelson |
#29
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I recently learned, to my surprise, that glacial acetic acid is flammable.
The article on reducing stress is very interesting, but it deals with faceplate removal from the bell by melting the frit which involves much higher temperatures. I suspect that the problem with the heat method isn't thermal stress, but that the PVA or other material has plasticizers in it. With PVA it's probably water. When you heat it the plasticizer becomes a gas and when trapped makes a high pressure between the cover glass and the face of the tube. I seem to remember in an earlier cataract removal thread someone saying that bubbles would form as they used the heatgun. John |
#30
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well something is getting nasty, the water is def getting murky looking, and I am seeing life forming in the way of little larve looking nasties, yuk...
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Audiokarma |
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