cracked up

[veronicaMars]

About a week ago ago i took my glasses to the place where i bought them because one of the screws that holds the lens in place kept coming out. i thought the screw might be stripped and they could replace it. The next day i noticed a crack in the lens. it was in the upper left of the left side of the lens. i took the glasses back and asked them what they did to the screw. The lady told me she used loc-tite not sure how to spell that. i showed her the lens and asked her if it would be ok. She said it would be fine and not to wory
well it was just a few day later and i noticed the crack was longer. i can see it from the corner of my eye now. This time she offered to sell me a replacement lens for a discount. i told her i thought they cracked it by tightening the screw too much and i shouldn't have to pay for it. then she called the store manager out to explain to me that it was the extreme temperatures that did it. Going from an air conditioned building to a hot car and that after a while it can cause the lens to crack. i never heard this before. i thought polycarbonates weren't supposed to crack. How bad will it get? Will the crack eventually go all the way to the other end? she wants $120 to give me a new lens but i'm a student. i don't have it. if the crack goes all the way to the bottom will they break?

[Dave Nelson]

loc-tite can cause polycarbonate to crack.

[Audiyoda]

she called the store manager out to explain to me that it was the extreme temperatures that did it. Going from an air conditioned building to a hot car and that after a while it can cause the lens to crack. i never heard this before. i thought polycarbonates weren't supposed to crack. How bad will it get? Will the crack eventually go all the way to the other end? she wants $120 to give me a new lens but i'm a student. i don't have it. if the crack goes all the way to the bottom will they break?

Hi VeronicaMars - sounds to me like someone used Loctite when they shouldn't. Polycarbonate can certainly crack when it's exposed to loctite. Loctite threadlock actually has a solvent in it designed to clean theads before the bonding agent can do it's job. That solvent is acetone based - acetone reacts with the molymer Bisphenol A in the polycarbonate reducing it to it's core component phenol - hence the cracking or crazing.

That crack is certainly the fault of the optician that helped you - not the fault of temperature extremes. Plastic or polycarbonate lenses can tolerate high degrees of temperature extremes before they would crack or craze. Quite honestly, that's one of the poorest excuses I've heard an optician use...ever. That manager should be ashamed to have treated you that way.

[Johns]

Print this thread and take it back to them.

Let us know what happens.

[Chris Ryser]

Print this thread and take it back to them.
Let us know what happens.

You can also add, that if thet would have sealed the microscopic cracks they made while drilling the holes, after the drilling, with drillseal, it would never have happened.

See at http://optochemicals.com/products/info_drillseal.htm.

[shellrob]

I agree, they messed up big time and need to pay to replace your lens. There's no excuse. Blaming it on the weather...come on now, that's ridiculous.

[Audiyoda]

You can also add, that if thet would have sealed the microscopic cracks they made while drilling the holes, after the drilling, with drillseal, it would never have happened.

See at http://optochemicals.com/products/info_drillseal.htm.

Chris I don't believe these are drill mounted lenses. It is my interpretation that she has a metal frame with a eyewire screw that was either stripped or loose.

It's my opinion that they used far too much loctite and it spread into the eyewire during lens insertion.

But if this is/were a drill mount situation, you are 100% correct.

[Cindy K]

A most unfortunate situation that would not have occurred if the person working on your glasses was knowledgeable in lab/workbench practice. A mistake or accident can happen to anyone in the lab or on the workbench but they should most definitely accept the responsibility for their obvious error.

I've kicked myself around the lab before for doing something stupid but never, never stuck it to the client to pay for my error. Shame shame :finger: