Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Early Color Television

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #16  
Old 04-08-2011, 08:50 AM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,159
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.
__________________
Evolution...
Reply With Quote
  #17  
Old 04-08-2011, 09:29 AM
VintagePC's Avatar
VintagePC VintagePC is offline
Tube bug got me 05/2010
 
Join Date: May 2010
Posts: 535
Quote:
Originally Posted by miniman82 View Post
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.
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.
Reply With Quote
  #18  
Old 04-08-2011, 02:42 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
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...
Reply With Quote
  #19  
Old 04-08-2011, 02:57 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 14,758
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.
Reply With Quote
  #20  
Old 04-08-2011, 04:40 PM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,159
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.
__________________
Evolution...
Reply With Quote
Audiokarma
  #21  
Old 04-08-2011, 05:18 PM
VintagePC's Avatar
VintagePC VintagePC is offline
Tube bug got me 05/2010
 
Join Date: May 2010
Posts: 535
Quote:
Originally Posted by miniman82 View Post
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.
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.
Reply With Quote
  #22  
Old 04-08-2011, 11:31 PM
Findm-Keepm's Avatar
Findm-Keepm Findm-Keepm is offline
Followin' the Rules...
 
Join Date: Jun 2007
Posts: 2,832
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.
Reply With Quote
  #23  
Old 04-09-2011, 12:04 AM
ctc17 ctc17 is offline
VideoKarma Member
 
Join Date: Jul 2009
Posts: 1,615
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.
Reply With Quote
  #24  
Old 04-09-2011, 11:16 AM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,159
So, stick the tube in a vat of vinegar?
__________________
Evolution...
Reply With Quote
  #25  
Old 04-09-2011, 11:26 AM
VintagePC's Avatar
VintagePC VintagePC is offline
Tube bug got me 05/2010
 
Join Date: May 2010
Posts: 535
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.
Reply With Quote
Audiokarma
  #26  
Old 04-09-2011, 12:21 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
dumped in 1/2 gal of vinegar...
Reply With Quote
  #27  
Old 04-09-2011, 12:37 PM
leadlike's Avatar
leadlike leadlike is offline
VideoKarma Member
 
Join Date: Apr 2008
Location: Lancaster, Pa
Posts: 956
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.
Reply With Quote
  #28  
Old 04-09-2011, 12:51 PM
Phil Nelson's Avatar
Phil Nelson Phil Nelson is offline
VideoKarma Member
 
Join Date: Jan 2006
Posts: 4,030
Quote:
Originally Posted by DaveWM View Post
I can see that I will have to keep an eye on it for evaporation losses.
You can make a little tent with a blue tarp or taped-together garbage bags. Could help with smells, too.

Phil Nelson
Reply With Quote
  #29  
Old 04-09-2011, 02:44 PM
jeyurkon's Avatar
jeyurkon jeyurkon is offline
VideoKarma Member
 
Join Date: Oct 2008
Location: Central Michigan
Posts: 1,698
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
Reply With Quote
  #30  
Old 04-09-2011, 07:15 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
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...
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:51 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.