Zenith Halo Cataract Removal, How I Did

[freakaftr8]

Yep, Chris's CTC-16's cataract proceedure was done using Dougs method. That CRT gel was nasty!!

[ChrisW6ATV]

Sean, I still have the CTC-16 combo in your picture, plus a TV-only one that I picked up last summer in Reno.

[DaveWM]

I wonder if there is a solvent that would just soak in and breakdown the bonding agent? just thinking out loud with a 3rd way to remove the glass.

I just got a nos 25" RCA tube that has a bad cateract (was in the box) and it seems like the bonding agent is very thick at the edges and rock hard.

[jr_tech]

Originally Posted by DaveWM

I wonder if there is a solvent that would just soak in and breakdown the bonding agent? just thinking out loud with a 3rd way to remove the glass.

I just got a nos 25" RCA tube that has a bad cateract (was in the box) and it seems like the bonding agent is very thick at the edges and rock hard.

I don't think that alcohol, acetone or any of the more common solvents will touch it. IIRC, methylene chloride, or perhaps MEK was used back in the day to clean up the dispenser after CRTs were laminated.

jr

[andy]

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[Eric H]

I seem to recall someone tried soaking one in a wading pool full of plain water once with good results, took several days but no danger of implosion.

It may not work with some types of adhesive.

[wa2ise]

You may want to use a full face shield, the sort welders use. Flying glass could get past the glasses. Besides, flying glass on bare face skin won't be a picnic even if it stayed out of the eyes.

[jeyurkon]

Originally Posted by Eric H

I seem to recall someone tried soaking one in a wading pool full of plain water once with good results, took several days but no danger of implosion.

It may not work with some types of adhesive.

That makes a lot of sense since PVA was used.

Originally Posted by wa2ise

You may want to use a full face shield, the sort welders use. Flying glass could get past the glasses. Besides, flying glass on bare face skin won't be a picnic even if it stayed out of the eyes.

I second that. Where I work, full face shields over safety glasses are required when grinding. Flying glass would be worse. I'd worry about the neck area too.

[DaveWM]

well I have a swimming pool, I may just go set it face down in there and let it be for a week or two, just the face of course I dont want to rust the anode or pins.

[sampson159]

a small wading pool is perfect.you dont have to fill it up all the way.enough water to submerge the safety glass only.i have used many methods.one effective was the use of wd 40 and a heat gun.spray it into a loose edge and watch it penetrate .use of the heat gun forces it to spread,loosening the glass.it speeds the progress tremendously.the hot wire,hammer and chisel,piano wire,etc.i think i have ran the gamut.the wading pool is the safest,but also the most time consuming!

[DaveWM]

ok I will will do the wading pool approach and report back, no hurry since I dont need this CRT right at the moment.

[Electronic M]

What would be a good gauge of wire for the Zenith cateract process? should one just pick one that heats well with whatever transformer is avalible or is a speciffic guage needed?

Will soaking work on Zenith cateracts too? Or is it only effective with RCA tubes?

The sun is so hot in the afternoon here that another tube I have with an RCA cateract was unbonding well before the sun started going down so preheating is not a problem.

Tom C.

[DaveWM]

with the zenith I used a .07 ss wire (think it was saftey wire used securing nuts and bolts). You don't even need a heat source if the tube is warm just from reg sun, the green stuff is gooey, you can just pull it through. I wrapped the wire on a couple of wood dowels for better hand holds and just pulled it no heat from power source required. this was on a zenith roundie. The goo was leaking out a small hole I poked in the tape that goes around the edge. the RCA stuff is rock hard.

[RCAkid]

So the hot wire method works on the RCA tubes as well then?

If so, that would make the problem a little less dangerous.

[DaveWM]

no the hot wire did not work at all on RCA tubes. for those soaking in water to get the adhesive pliable, them tug out the edges of the adhesive, put the tube in the sun on a hot day and use small wedges all around the perimeter. Tap them in just a bit and then leave it for 15 min, tap them in again (they will loosen up as the bond breaks down), go away for 10 min, keep doing this. you can see the bond breaking down in the bright sunlight, it will look like tiny fissues forming. The key is to just do it slowly and evenly around the rim. As it progresses the bond will break down into a nearly perfect circle and then just pop, and the whole lens will jump off the CRT. It also accerates the debonding as it goes (less bonded area, faster the remaining bond lets go).

the sun heat is key. the water soak makes it easier to get the wedges in.

I have one out in a pool for months and its still on there, so no telling how long it would take to just come off with out the heat and pressure.

I think the main thing is to avoid the heat gun approach as the heat is too concentrated, the sun is a more even approach.