I recently fabricated and installed a new window from plexiglass sheet. Once installed, I removed the protective film and found that the window has an odd distortion. It’s a bit hard to describe, but it’s like it has thousands of faint lines across it horizontally. They are spaced about .010” and .125” apart from each other (fractions of a millimeter up to about a millimeter or so) and cover 100% of the window area. These lines appear to be IN the plexiglass vs on the surface. I cannot feel any deformation or scratch on the surface. These lines have the effect of giving a slightly distorted view of things through the window.

Has anyone seen this before? Any clues as to what the cause might be? More importantly, is there a remedy, short of replacing it? I’m about ready to pull it out, but would love to avoid that if there is another solution. I’ve thought about trying a plastic polish (mild abrasive) but I’m skeptical that it would make a difference, as the defect does not seem to be on the surface.

I did have to flex the window somewhat to get it into place (this is the optional large observer window on the left side rear) so perhaps that had something to do with it? Or was it just a defective piece of plexiglass?

Thanks for any insights.

Andy, I recently replaced the same window and like you, I had to bend or bow the heck out of it, to get it past the door jam and behind the frame tube, but after pulling the wax paper shielding, I did not have any distortion. I don't think it's anything that you did. It sounds like a bad piece of glass. I bought mine from Great Lakes, It's there gray tented low E material and it's clear as a bell.

Same here distortion free. That left side observer window is a pain to get in without scratching it all up even with the protective film still in place. That said mine was still clear and scratch free until the latest wind storm pulled the down limit cable brackets down the hinge tube and allowed the flaps to put scratches in the side windows again. That's why I replaced them last time too.