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Old 12-06-2017, 10:41 PM   #16
AnotherCat
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Quote:
Originally Posted by barryem View Post
I read an article about the advantages of plexiglass over glass in certain situations probably 30 or 40 years ago. I don't recall the situations it referred to but I do remember that plexiglass allowed 90 times as much light to pass as does glass...

...Please don't take any of this as decisive. It's just a reason to wonder about assumptions.
Have had quite a bit to do with glass, acrylic and polycarbonate, mainly for marine hatches and windows. So -

In fact clear acrylic (e.g. Plexiglass, Perspex) transmits only about 2% more light than clear glass does - it varies slightly according to the glass. It has never been "90 times as much" .

The other common similar plastic polycarbonate (e.g. Lexan) transmits about the same as glass. It is generally softer than acrylic so scratches more easily and is less resistant to UV.
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