Refraction

[bill lambeth]

Why do some legs show refraction and some don't ?I had a call to one of my fleets and it was a old repair.When I looked at it first I though dang look at that leg that failed to fill but then I sat in the seat and looked directly at it and it was not there.I totally understand the light coming through and hitting the lamenent but why some do and some don't ?

[SeeClearly]

My understanding and experience is that the light refracts off the plane of the crack, not necessarily the laminate. I am not a light expert, but know that most of the time my repairs only show the silhoutte of the legs not any planes unless they are simply not filled. If the light is refracting off the break plane and there was resin in it before, maybe it has split and the resin that was in the leg has "stuck" to one side of the crack and not the other. Hence you would see the light refract on the new spreaded leg, while the view from the inside might be not visible since the refraction of light is not as apparent if the resin stuck to that side of the crack. Just a thought.

[screenman]

Are you seeing refraction in the glass or a mark in the PVB? was the damage perfectly dry? Moisture has an unusual way of making it way through cured resin to leave what looks like shrinkage a few days later. How new is your curing bulb? This can effect the speed the resin cures, which I have found can change or looks like it changes the refraction of the cured resin.

[bill lambeth]

Screenman not sure who repair it was mine or someone else.The repair was good but one leg was showing more refraction than the others.All the legs were filled.I could look at this one leg from the side and it appeared not filled.I mean it was black but I got in an looked at it straight on and from the other angle and you could see nothing.Kind a puzzled me

[screenman]

Black is air so obviously it was not filled or it was filled at some time and the bond failed. When doing a repair it is of the utmost importance to cross reference your work, by this I mean look from as many angles as possible. I often show in training how we can make a unfilled repair look partially filled just by looking from different angles, I feel it is all about the way you are seeing the refracted light, the greater the area you view the more you see. Think of a leg as a coin standing on its side, viewed from the top you only see a thin edge, move your angle of view and more becomes visible, we know that legs do not always run perpendicular to the surface which is why we have to change our viewpoint often.