Plastic window - what are the best materials?

[Chris Green]

I want to replace a window in our boat with plastic, it needs to be

5mm thick but apart from that there's no particular limitations. What's the best type of plastic for scratch resistance and transparency?

[Brian Gaff]

Polycarbonate i suppose. However what was there before? Brian

[T i m]

I'm not sure any plastic is particularly scratch resistant but I think I'd go for either Perspex or (stronger) polycarbonate / Lexan?

I know the bodyshells or RC cars are often made of polycarbonite and they are glass clear before painting.

Both are available on eBay etc.

Cheers, T i m

[Dave Plowman (News)]

None - if car headlights are to go by. It will eventually go cloudy.

[Brian Gaff]

The plexiglass used in my old Greenhouse had a blue tinge to it, and was always clear and quite bendy, better than perspex which cracked and went milky and hated bending.

I imagine ist was polycarbonate as when we broke one I bought a sheet and it was almost identical.

Brian

[Harry Bloomfield]

Brian Gaff wrote on 26/08/2017 :

That will quickly go milky on the surface due to UV attack, Plexiglass doesn't and is used for caravan windows. I understand you can get a spray to spray on Polycarbonate, which protects it and headlights from the effects or at least delays it.

[T i m]

But you can also get polycarbonate sheeting that is already UV protected.

Cheers, T i m

[newshound]

Plexiglass and perspex are just commercial tradenames for poly methyl methacrylate

[Bill]

In message , Chris Green writes

I 'liberated' a couple of transparent hinged covers from silencing cases for, I think, telex machines, and they have provided plastic for all sorts of jobs, including my boat replacement windows. The plastic is slightly darkened, like the stupid privacy glass on cars, but you don't notice it unless you know to look. It was cut and drilled without cracking and has worn well. Our boat windows are just ovals bolted, using "sex bolts", over the oval cutouts in the wood.

I've no idea, of course, what the plastic is.

[newshound]

Well that is a term I had never heard before

[Bill Wright]

I used some makrolon that was advertised as having UV resistance and it's been fine.

Bill

[Chris Hogg]

[Robin]

JOOI, why plastic rather than glass?

[Chris Green]

Where do I get a weird, round cornered, five sided sheet of safety glass?

[Tim+]

Any glazier? Given them a template and they will cut and then toughen the glass.

Tim

[dennis]

Be aware that its frequently only on one side so make sure you put it the right way around.

[Harry Bloomfield]

It is only a very thin coating and eventually will deteriorate, as many find with headlamp lens's on cars. The milkiness can be polished off, but returns even more quickly once the thin UV protection coating has been lost.

[Robin]

I agree with others that a glazier will make (or more often send away to be made) toughened glass to your template. If your current window is plastic and not too brittle they might even be able to use that if you could cope with a temporary board in its place.

But IMLE "weird" is not a specification they'll guarantee to meet :)

[news]

Margard is a polycarbonate with a hard surface, was fine in forestry kit as long as you didn't use the wipers.

AJH

[Chris Green]

Well what we actually need is toughened glass to a template with 2mm shaved off one edge.

Maybe not, it just seemed to me that it was a very odd asymmeteric shape. :-)