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#1
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Will a windshield repair kit fix a dinged condenser lens?
I accidentally dinged the flat side of a condenser lens with the edge
of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Will one of these windshield repair kits with a sunlight hardened resin make the ding optically invisible - i.e. so that it doesn't cast a shadow when projecting through it, or is pointless to try? Don't want to spend the $11 if it's not going to work. Is there any kind of repair material for this kind of thing? If that method isn't going to work, it's my understanding DIY lens grinding is possible. Do you think it would be possible to grind down the flat side of the lens past the point of the damage? Any links to directions on how to do it? Where's a good place to get materials to do this? I know, the lenses aren't expensive but I hate to waste an otherwise good one. I assume it would change its focal length slightly but it's probably not crucial for my purposes. Thanks for all input. |
#2
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Will a windshield repair kit fix a dinged condenser lens?
Doc wrote:
I accidentally dinged the flat side of a condenser lens with the edge of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Will one of these windshield repair kits with a sunlight hardened resin make the ding optically invisible - i.e. so that it doesn't cast a shadow when projecting through it, or is pointless to try? Don't want to spend the $11 if it's not going to work. Is there any kind of repair material for this kind of thing? If that method isn't going to work, it's my understanding DIY lens grinding is possible. Do you think it would be possible to grind down the flat side of the lens past the point of the damage? Any links to directions on how to do it? Where's a good place to get materials to do this? I know, the lenses aren't expensive but I hate to waste an otherwise good one. I assume it would change its focal length slightly but it's probably not crucial for my purposes. Thanks for all input. It's doubtful that the acrylic resin will have the same optical characteristics as the glass; even though it appears the same color the refraction and dispersion is bound to be different. That translates to image distortion for the rays that pass through the resin. Grinding a new flat surface won't change the focal length significantly, but it will be a lot of work, hours and hours, and then checking for optical flatness is not simple. Far better to junk it and get another. Colin D. -- Posted via a free Usenet account from http://www.teranews.com |
#3
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Will a windshield repair kit fix a dinged condenser lens?
Colin_D writes:
Doc wrote: I accidentally dinged the flat side of a condenser lens with the edge of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Will one of these windshield repair kits with a sunlight hardened resin make the ding optically invisible - i.e. so that it doesn't cast a shadow when projecting through it, or is pointless to try? Don't want to spend the $11 if it's not going to work. Is there any kind of repair material for this kind of thing? If that method isn't going to work, it's my understanding DIY lens grinding is possible. Do you think it would be possible to grind down the flat side of the lens past the point of the damage? Any links to directions on how to do it? Where's a good place to get materials to do this? I know, the lenses aren't expensive but I hate to waste an otherwise good one. I assume it would change its focal length slightly but it's probably not crucial for my purposes. Thanks for all input. It's doubtful that the acrylic resin will have the same optical characteristics as the glass; even though it appears the same color the refraction and dispersion is bound to be different. That translates to image distortion for the rays that pass through the resin. It might be less visible than the scratch he has now though. Grinding a new flat surface won't change the focal length significantly, but it will be a lot of work, hours and hours, and then checking for optical flatness is not simple. Far better to junk it and get another. Grinding will also remove any coating from that surface. Probably not a good idea. -- Måns Rullgård |
#4
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Will a windshield repair kit fix a dinged condenser lens?
In sci.optics Doc wrote:
I accidentally dinged the flat side of a condenser lens with the edge of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Colour it in with black marker. |
#5
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Will a windshield repair kit fix a dinged condenser lens?
Ian Stirling wrote: Colour it in with black marker. Clear varnish is better. Instead, if it is one of a pair of identical lenses (convex sides inwards) just reverse the two to get the damaged surface away from the focal plane. Brian Ancient and Modern Optics |
#6
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Will a windshield repair kit fix a dinged condenser lens?
Ian Stirling wrote: Colour it in with black marker. Clear varnish is better. Instead, if it is one of a pair of identical lenses (convex sides inwards) just reverse the two to get the damaged surface away from the focal plane. Brian Ancient and Modern Optics |
#7
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Will a windshield repair kit fix a dinged condenser lens?
Actually works but something a little more opaque is better,
you can fill small scratches with India Ink and "dings" with black brushing lacquer. darkroommike Ian Stirling wrote: In sci.optics Doc wrote: I accidentally dinged the flat side of a condenser lens with the edge of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Colour it in with black marker. |
#8
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Will a windshield repair kit fix a dinged condenser lens?
You might want to try Canada Balsam. It is used to
glue lens elements together as it has the same refractive index as glass. Also used to mount microscope specimens on slides and a scientific store would be the place to start looking. Be warned it ain't cheap. Maybe you know someone who works in a lab doing pathology? Murray Doc wrote: I accidentally dinged the flat side of a condenser lens with the edge of another lens, made a small gouge probably a couple of 1/1000ths " deep give or take - I can feel it with a fingernail - and it's quite visible when projecting an image through it. Will one of these windshield repair kits with a sunlight hardened resin make the ding optically invisible - i.e. so that it doesn't cast a shadow when projecting through it, or is pointless to try? Don't want to spend the $11 if it's not going to work. Is there any kind of repair material for this kind of thing? If that method isn't going to work, it's my understanding DIY lens grinding is possible. Do you think it would be possible to grind down the flat side of the lens past the point of the damage? Any links to directions on how to do it? Where's a good place to get materials to do this? I know, the lenses aren't expensive but I hate to waste an otherwise good one. I assume it would change its focal length slightly but it's probably not crucial for my purposes. Thanks for all input. |
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