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NeXT
July 1st, 2016, 08:16 AM
Finally! A proper video for people with smaller tubes on how to remove those nasty cataracts you've developed on your terminal or video display.
Filmed and edited by yours truly with no hidden tricks or skipped steps. The entire job from start to finish in 45 minutes.

https://www.youtube.com/watch?v=4zKnRoNc9Q0

Chuck(G)
July 1st, 2016, 09:04 AM
There are similar YT videos for handling large TV tubes. I've wondered what would happen if one simply took the (small) CRT and placed it in a kitchen oven and heated it to 300 F.

NeXT
July 1st, 2016, 09:26 AM
Yeah, there was nothing for smaller tubes so I've come across a few people who were cautious on using the same technique on the assumption the process would not safely scale down. It does scale down fine but I still wouldn't suggest placing a tube in an oven as should it fail you've now contaminated your oven, plus I don't like the idea of handling hot glass.

glitch
July 1st, 2016, 09:36 AM
Thanks for taking the time to put this together! I used pretty much this exact method to deal with deteriorated PVA on my ADM-3A's CRT tube. Not too difficult, and having this video available will probably convince others that they can do it too!

Chuck(G)
July 1st, 2016, 10:38 AM
Yeah, there was nothing for smaller tubes so I've come across a few people who were cautious on using the same technique on the assumption the process would not safely scale down. It does scale down fine but I still wouldn't suggest placing a tube in an oven as should it fail you've now contaminated your oven, plus I don't like the idea of handling hot glass.

I'd probably recommend oven heating with the CRT wrapped in a couple of burlap bags. That way, if it breaks, there's no danger of the bits getting into the wrong places. I believe that part of the manufacturing process is to heat the bottle during evacuation in order to allow the innards to "out-gas". The temperatures must be in excess of 300F. Allowing it to cools slowly could even relieve some stresses in the tube.

gertk
July 1st, 2016, 10:59 AM
I would suggest safety goggles and non slip safety gloves!
Dislike the heatgun also...

glitch
July 1st, 2016, 11:33 AM
Dislike the heatgun also...

Why? No problem as long as you don't go nuts with it. Before buying a heat gun, I'd have probably used a blowtorch with a fan tip.

geoffm3
July 8th, 2016, 12:02 PM
I'd probably recommend oven heating with the CRT wrapped in a couple of burlap bags. That way, if it breaks, there's no danger of the bits getting into the wrong places. I believe that part of the manufacturing process is to heat the bottle during evacuation in order to allow the innards to "out-gas". The temperatures must be in excess of 300F. Allowing it to cools slowly could even relieve some stresses in the tube.

If that happened, I wonder what sort of heavy metals and whatnot you'd have to worry about inside your oven contaminating your food?

Chuck(G)
July 8th, 2016, 12:44 PM
Wrapped in a burlap bag? A sealed glass CRT? At 300F? :huh:

NeXT
July 8th, 2016, 01:02 PM
It's not a thing I'd recommend to others, at least not publically in a video designed for educational purposes. Last thing I want are angry messages on youtube on how their tubes imploded or they had to be hospitalized for burns and glass cuts because of shenanigans in their oven. The heat gun method is proven to work on almost all makes and model tubes (and you saw me wearing basically no safety protection besides glasses because I have that much trust in the method) with the exception of Zenith tubes where a green halo indicates a different chemistry of the bonding material and a hot wire will be needed instead to remove the glass.

geoffm3
July 8th, 2016, 01:13 PM
Wrapped in a burlap bag? A sealed glass CRT? At 300F? :huh:

Not all the innards are going to remain in the burlap bag if the CRT implodes, and IIRC there are some nasty compounds inside them.

Chuck(G)
July 8th, 2016, 02:44 PM
At very low concentrations. Cesium, thorium, etc. There's probably some rare-earth compounds in the phosphor as well as the usual zinc sulfide. Most of the lead is in the frit seal, which doesn't fragment into dust. No mercury, arsenic, etc. But the bulk of the space occupied by a CRT is vacuum.