View Full Version : PVA cataract removal No Heat!


marty59
10-01-2011, 05:19 PM
Yes, I accomplished my first successful cataract removal using the water soak method and tongue depressors as wedges!

You may recall the CTC-20 that I had picked up earlier this year and it's tube was my patient. I'll step through what I did as I'm very pleased about not having to use any heat and I didn't stress the tube in any way either!

Prior to soaking, I removed the tape and I trimmed/peeled as much of the PVA as possible, which was the outermost diameter where the safety glass sticks out past the CRT bell/face.

I'm not sure how long is enough, but my tube ended up soaking for about three months before I had the opportunity to work with it.

Upon facing the CRT up on my plastic drum, the PVA had degraded the most around it's outermost edges had now became pliable and had fissures/cracks throughout. I was able to take one of my depressor sticks and break out most of it. After this, I let it soak for another week. There sure was some slimey stuff floating in that water!

I don't know if I really needed to let it soak more, but at this point it really didn't look like it made much of a change so now was the time to figure out what to do next.

I noticed that I was able to put my sticks into not only all around between the safety glass and the tube, but I was able to determine that one area had more clearance......an area about a third of the face. I also took some tape from the face to the side in three places and left some "slack" in it, in case the front decided to pop off without landing on the floor and breaking.

Sooooo.....I thought to myself about doubling up the thickness of my sticks and let it set some more if needed. I was able to slowly work them in but only to the point of feeling pressure that I stopped. Lo and behold, I could see a line moving across the face! After about an hour or so the seperating stopped and I retightened my tongue depressors and marked my line of progress and called it a day.

My "parting" line had moved almost halfway across and now I was able to take some door-frame installation wedges and work them in some and then stopped...okay, time to walk away!

My next day after I noticed that my parting line had not moved much, but I took a long cable tie and stuck it in to see if I could detect any seperation and where. Fortunately, I was able to stick it in almost to the halfway point between the PVA and the safety glass front where it was wedged the most. Obviously, my clearance was getting greater and I was able to move my wedges more. Then...Pop! It broke free and easily too! The safety glass stayed in one piece and very little effort was needed. The PVA stayed stuck to the CRT and it peeled right off.

In closing, I realize that wedging has not always been successful for some of you but not only did it work for me, but I knew when to walk away and leave it alone. After all, the next day you can check your progess and determine your next move. At this point I "may" have thought about using some heat but I concerned myself with uneven heating and stressing the tube which I wanted to avoid at all possible.
Another thing, the PVA material was still adhering in the inner most diameters of my CRT originally, and I believe that it's like a suction cup effect. You can't remove it from the center but you can by starting from the side...Hence the wedge procedure!
And, after a good cleaning I made a couple of clear sllicone dots, let it set up and then finished around the whole thing. It came out pretty good!

We have been fortunate to have learned alot about removing cataracts and I thought it best to share my experience. You can't help but become a little fearful since not having done this before and I sure fell better after accomplishing this. I can't help but recall the time Doug was working on that 23EGP22 that went boom! I'm thankful to all of you that have made posts here as well as on YouTube to share your experiences.

Kevin Kuehn
10-02-2011, 01:04 AM
Thanks for posting your findings.

So as I understand you used a slow side to side peeling process (wedges on only half), rather than wedges all around the perimeter?

marty59
10-02-2011, 09:46 AM
Yes, to your question.

However, on the opposite side that was tighter I did insert single sticks (did not try to wedge 'em).

As the side that I wedged started to open up, those single layer sticks did tighten as the safety glass was starting to rest up against them by the tilting motion. My thoughts were being that the thing to do was to maintain that clearance and not have glass to glass contact as a pressure point, as well as no downward pressure on that side of the PVA by decreasing that clearance. Plus with those single layer sticks in there I could gauge that pressure by detecting how loose/tight they were. I sure did concern myself with breaking the safety glass but wanted to maintain upward pressure and know when to walk away to call it a day!

Even though it took me about 4 days to seperate the two, I always had the next day to look at it and see how I was progressing.

bgadow
10-02-2011, 10:34 PM
Very nice! It can be real hard to stay patient, but that is the key. I have broken a safety glass by pushing too hard on the sticks. Not the end of the world but it did ruin my day.

ChrisW6ATV
10-06-2011, 01:21 AM
Thank you for posting your successful process, Marty. I did one CRT with a heat gun, but that was before two other VK members had CRTs implode. My Magnavox set needs its PVA removed, so I will try the non-heat method on it. I might have done it with heat if I had had time recently when it was hot outside here (so I could get the whole CRT hot by leaving it in the sun for a few hours before using the gun), but now I think our hot weather is done for the year.

Electronic M
10-06-2011, 12:27 PM
I'm a fan of the sun method. It gradually/evenly gets the tube hot enough to pop the lense, and is quick enough to keep me from going nuts.

ChrisW6ATV
10-07-2011, 01:50 AM
Is the sun method a combination of face-up CRT and slow wedging of sticks in the edges on a hot day? Or, over several days?

DaveWM
10-07-2011, 08:26 AM
Sun method is one day, I think it took about 1 hr total when I did it. just set it out with the face up, let it get warmed up (about 30 min on a hot florida day), insert wedges (chop sticks for me) around the perimeter, tap them in until just snug, walk away for 10 min, check them, tap in some more until snug, repeat. You can see what looks like fissures developing in the pva as it starts to release, at 1st its uneven (some sticks will snug up more that others), but as it progresses you will see a perfect circle form (the remaining contact point), and it will accelarate as it progresses. the main thing is to not over do the snug process, you just tap them in until "just" snug, not trying to pry it off, just apply even pressure. I had them about every inch around the perimeter.

I also preceded this by soaking the face of the tube (and the pva) in a small kidde pool for about 1 month in tap water. this softend up the rock hard pva a lot. I was able to then pick out about 1-2 inches of the pva around the edges, providing a space to insert the chop stick wedges.

ChrisW6ATV
10-08-2011, 01:40 PM
Thanks, Dave.