Removing Scratches from CRTs

[Chris F.]

A friend brought me a load of old TVs and stuff he'd rounded up from city
trash day, and amongst them was a set I hadn't heard of a before - a Loewe
Calida. I thought it was an old studio monitor or something, but looking
around on the internet I see it is actually a premium - and pricey -
television set. Trouble is, it has a big ugly scratch along the top - very
shallow but still enough to hurt the image. Is there any way to remove, or
at least hide/mask, scratches on CRT faces? I have a number of nice sets in
my stock that have minor scratches and chips on the faces - nothing large,
just enough to reduce the sets value to the point where it isn't worth
repairing.
The Loewe is actually dead, I just wanted to see if I could repair the CRT
before trying to get the set going. Not a chance of replacing it - it's some
weird Philips "Black Matrix" which would be impossible to obtain.
Thanks for any advice.

 

[cnctut]

Chris--

Only a guess--how about an auto window repair kit--they do pretty well
on stone and pebble damage to windshields.

Tut

 

[Art]

One method many resort to is to actually polish the scratch out of the face
of the crt, if it is not too deep. However it may distort the display. Will
take a considerable period of time and require delicate polishing
techniques.

 

[NSM]

Chris--

Only a guess--how about an auto window repair kit--they do pretty well
on stone and pebble damage to windshields.

I've used those. I suspect a version might work best.

 

[Sam Goldwasser]

One method many resort to is to actually polish the scratch out of the face
of the crt, if it is not too deep. However it may distort the display. Will
take a considerable period of time and require delicate polishing
techniques.

And, if there is an antireflective or textured coating, will probably
make it look much worse.

No one has mentioned the safety issues. How deep are the scratches?
If they are really bad or extend over a large area, there may be increased
risk of implosion.

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[NSM]

I've used those. I suspect a version might work best.

"I suspect a vacuum version might work best".

 

[Chris F.]

The scratch on the Loewe is very shallow, not even deep enough to catch a
fingernail. Not a safety hazard considering that most CRT glass is about
1/2" thick at the face.
After some fiddling around last night, I realized that the Loewe was
actually a European set designed for 220V operation. So I hooked it up to
some 220, and it powered up just fine. Unfortunately, it's a PAL set with
some very strange connectors, so I'm going to need some conversion equipment
before I can tell if it works right. The image quality of the onscreen menu
is outstanding - obviously a very high end set. Even uses a 100Hz scanning
rate. I suspect I could get quite a bit of money out of this, if I could
confirm that it works properly.

 

[mydigcam]

Might try putting a bit of traditional toothpaste on a soft clean cotton
cloth and rub over the scratch. If this has no effect, then that's about all
you can do other than replace the CRT or live with it.

 

[none]

Might try putting a bit of traditional toothpaste on a soft clean cotton
cloth and rub over the scratch. If this has no effect, then that's about all
you can do other than replace the CRT or live with it.

They make all types of buffing compounds for glass and plastic.
The question is, is the scratch deep? If so even if you buff down to
smooth glass you'll get distortion at the buff area.
They also make a filler for windshield repair that might work.

 

[PaPaPeng]

The scratch on the Loewe is very shallow, not even deep enough to catch a
fingernail. Not a safety hazard considering that most CRT glass is about
1/2" thick at the face.

As per recommendations from others try buffing with toothpaste or a
metal polish like Brasso to get rid of as much of the visible scratch
as possible. Then use an acrylic floor polish sold as Future Wax (or
Future something, WalMart) to touch up the scratch . The acrylic will
modify the optical properties, much like damping it with water will
make the scratch invisible.

 

[NSM]

As per recommendations from others try buffing with toothpaste or a
metal polish like Brasso to get rid of as much of the visible scratch
as possible. Then use an acrylic floor polish sold as Future Wax (or
Future something, WalMart) to touch up the scratch . The acrylic will
modify the optical properties, much like damping it with water will
make the scratch invisible.

There's a scratch repair kit for eyeglasses that might work better.

 

[kip]

Dont use Brasso ...You will make it worse.
kip

 

[none]

Dont use Brasso ...You will make it worse.
kip

There's a scratch repair kit for eyeglasses that might work better.

DON'T use Brasso, and I doubt toothpaste will do much good.
USE a buffing compound made for glass or plastic.
I use one called NicSand. It's a buffing compound for plexiglass,
lexan and glass. I use the fine grit( 10,000 grit).
It's an Aluminum oxide sanding gel, perfect for plastic or glass.
It does come in coarser grades as well.
There are other brands on the market also.
Check in your yellow pages for Cadillac plastics or some other
commercial plastics dealer, they should have the compounds you need.
Also try any commercial glass supplier or place that makes stained
glass windows.(They use buffing compounds to restore antique glass to
a glossy finish, they should be willing to sell you a small amount of
the right stuff.)
As for the scratch repair kits, they can be had at your local Wal-Mart
or Pep Boys. It's just a clear acrylic or epoxy glaze that fills the
scratch in and restores uniform surface refraction.

 

[[email protected]]

The Loewe is actually dead, I just wanted to see if I could repair the CRT
before trying to get the set going. Not a chance of replacing it - it's some
weird Philips "Black Matrix" which would be impossible to obtain.

What is the model of this Philips tube? If it happens to be made in
France or Germany, and if the letters ESF are in the model number, it
may not last very long anyway, depending on how much use it already
had. These tubes are well known for various short circuits developping
in the gun assembly...