Plexi or Lexan to replace old boat windows??

[Frank]

Which is more scratch resistant, clouds less etc?
Anyone with experience?

[Godot]

As I recall, I used polycarbonate (Lexan) on my old Seafarer. It's not supposed to be as scratch resistant as Acrylic (plexi); but I don't recall any issues.

[Owly055]

Polycarbonate yellows with age..... acrylic does not.  Acrylic is clearer, and scratches can be polished out easily.  Polycarbonate is more chip resistant, but less scratch resistant.  Acrylic will withstand a greater uniform load, but polycarbonate is more flexible.  Acrylic is extremely stable chemically, polycarbonate is not, and will erode under some circumstances.  Acrylic is probably the most "food safe" of all plastics.  For toughness, polycarbonate wins.  It will flex and give under an impact, and is less likely to crack or craze.   If toughness is the priority, polycarbonate tends to win, if clarity and out and out strength is the priority, acrylic wins.  I speak from some personal experience.  You have to assess your needs, and decide.......... There are places where I prefer one and places I prefer the other.   As far as portlights on a boat, acrylic (plexiglass) of a heavy gauge would be my choice.   I don't like the fact that it can easily be damaged during drilling or cutting, and cracks can propagate........ and that should be a concern.   When hit by a breaking wave, the acrylic may let go.... depending on the way it's installed, while the polycarbonate may flex......... it's a tough call.


                                                                                      H.W.