Replacing acrylic windows - downgrade thickness?

dgadee

dgadee

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I have long thin acrylic windows (2000mm by 250mm) which each cover two smaller openings on the side of the coach roof. The current thickness of the acrylic is 10mm. These are 25 years old and I intend to replace them, but 10mm seems very substantial. Should I replace with that thickness or could I go for 5 or 6mm?

The 10mm seems harder to get in the appropriate tint.

Philip
 
Mine are a similar size and only 6mm thick.
The openings only cover about 50% of the overall size so that much of the perspex is fixed onto solid GRP.
 
This forum is so speedy! Thanks for that information - the central part under the window on my boat is solid grp too.

Philip
 
I would stick with 10mm.5 or 6mm will be too fragile and bendy.I once saw a Vancouver 32 that had several portholes stoved in by a large wave and the were around 6mm thick.
 
30boat said:
I would stick with 10mm.5 or 6mm will be too fragile and bendy.I once saw a Vancouver 32 that had several portholes stoved in by a large wave and the were around 6mm thick.
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The Vancouver has individual ports. My boat has a plexiglass screwed to the coach roof, so I would not be so concerned about a window being stove in. Difficult to see how it would happen. Original windows are acrylic and not in bad condition after so many years so will use same again - reason for replacement is mainly that if I rebed then just as well to replace.

Philip
 
dgadee said:
The Vancouver has individual ports. My boat has a plexiglass screwed to the coach roof, so I would not be so concerned about a window being stove in. Difficult to see how it would happen. Original windows are acrylic and not in bad condition after so many years so will use same again - reason for replacement is mainly that if I rebed then just as well to replace.

Philip
Click to expand...

My point exactly.Individual ports are stronger than a long acrylic window.
The only problem with thicker acrylic is that the expansion when hot will be larger making life difficult for the sealant.
 
30boat said:
My point exactly.Individual ports are stronger than a long acrylic window.
The only problem with thicker acrylic is that the expansion when hot will be larger making life difficult for the sealant.
Click to expand...

He has individual ports, at least two of them on each side, if my reading of #3 is correct. They just happen to be covered by one sheet of plastic.

I don't see why thicker plastic will expand more. In the shear plane won't the expansion will be exactly the same whether 5mm or 25mm thick?
 
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Rigger Mortice said:
He has individual ports, at least two of them on each side, if my reading of #3 is correct. They just happen to be covered by one sheet of plastic.

I don't see why thicker plastic will expand more. In the shear plane won't the expansion will be exactly the same whether 5mm or 25mm thick?
Click to expand...

Yes but the forces accross the thickness will be greater and put a lot of strain on fixings .In my experience this type of window is not the best.Keeping them thin does help but does nothing for strength.
 
Just left off the old windows as templates. Supplier had 8mm acrylic in blue (the colour I wanted) so have gone with that (but he didn't seem to think 6mm would be a problem strengthwise should I have gone down to that thickness). I am using Scarpa tape for bedding, so hopefully this will accommodate any movement.

Philip
 
I used tape rather than sealant and this has been perfect for last two years make sure any joins are not straight cut but zig zagged to give a perfect seal
 
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