Acryllic, perspex or plexiglass?

Greenheart

Greenheart

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This is just idle interest, thinking about what's possible.

I know the question of replacement windows comes up here (but not lately) and for the most part, glass may be best.

But for DIY construction on a small scale (not necessarily to standard sizes and shapes), alternatives seem to be lighter, not especially costly, possibly safer, much easier to work with and better at surviving impacts.

What I don't know is whether the relative softness of non-glass leads inevitably to scratching, misting, etc; and whether there are effective solutions to those issues, which make the alternatives good options for seagoing vessels.

So many boats have sadly opaque windows and screens (or is it just filth?) so I doubt I'm the only one wondering.

Thanks!
 
RichardS said:
Do any modern boats use glass? I thought acrylic/polycarbonate was universal these days?

Richard
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If long term transparency is a high priority, glass is an option worth considering. The main drawback is that it is heavier, but it is far more resistant to scratching and UV damage.

Many high end yacht windows are glass.
 
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noelex said:
If long term transparency is a high priority, glass is an option worth considering. The main drawback is that it is heavier, but it is far more resistant to scratching and UV damage.
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When I had the windows of my Hunter 490 (anyone want a Hunter 490?) rebuilt, I was amazed to find that toughened glass only cost a quid or two more per side than plastic. Well worth it.
 
Stemar said:
Glass would be my first choice, but my windows are curved, so plastic is the only realistic option
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It depends on the exactly shape, of course, but curved glass is quite do-able. If you have a suitable curved template the replacement can be shaped to fit when it's heated for toughening; otherwise it can be done by measurements. I was thinking of getting a front window in my Hunter 490, and C&J Windows (now gone, alas) were happy to make a curved glass one for me, for not too much.

My Jouster's windows were glass and had a significant curve sprung into the, to my surprise. Over an inch of displacement at the end of a two foot piece of glass.
 
Perspex and Plexiglax are trade names for Acryllic. (Someone will probably contradict but that's what I concluded after investigation.) A very long time ago we decided that curved glass was out of reach financially - so long that I can't remember the numbers. Perspex windows in Amulet lasted several decades. Didn't seem to be too much UV problem. However, the annnoying thing is that they scratch terribly. The ones that regularly made contact with the anchor chain became almost opaque with scratches. Replaced them all with more acryllic last winter. (UV does break down the sealant - best to get a UV resistant one.)
 
RichardS said:
Do any modern boats use glass? I thought acrylic/polycarbonate was universal these days?
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Our windscreen is toughened glass. It would probably be scratched to buggery if it was polycarbonate.

I'm actually not sure about the cabin windows, come to think of it; they might be glass too. The opening ports and hatches are either acrylic or polycarbonate though.

Pete
 
Stemar said:
Glass would be my first choice, but my windows are curved, so plastic is the only realistic option
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Steve

I had new glass windows made by Houdini for my boat in 2009 when I purchased her . They were bent first to my radius specifications then toughened afterwards , so bent glass is not a problem for some manufacturers.
It really is worth what little extra it costs.

Polycarbonate scratches easily, Perspex is harder but crazes eventually and goes opaque in the mean time.

I only wanted to do the job once, and the new windows included anodised ali through bolted frames as well, glass was the way to go IMO
I suppose it does depend just how much bend you require, I think there are limits?
Mine were 2 windows 1400mm x 210mm length with a 30mm bend , + 2 x 300mm x 140mm flat window. Price best part of a grand delivered - 2009

Look as good now as when first fitted and does add to the boats appearance.

Philip
 
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I replaced my wheelhouse front window with Polycarbonate supposed to be UV stable. It has gone a milky colour and scratched although I have been very careful when cleaning it. I would not use polycarbonate again.
I also replaced my side wheelhouse windows and they are beautifully clear and have no scratching visible or cracking around screw holes etc after 3 seasons.
I think unless you have a strength critical window like in a boat hull then acrylic is better and cheaper than polycarbonate although glass probably best of all, apart from price. I dread tothink what my front wheelhouse window would cost in glass at about 55" x 30".
 
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Do you have frames and what state are they in? Some frames are designed to never be dismantled and reglazed - instead they are permanently crimped (had this on my Liberty). Even the professionals were reluctant and the quote was astronomical.

If you can re-use the frames, why not get the glass? If you can't, you're probably going frameless - acrylic is the most common choice (and yes Plexiglass and Perspex are brands of Acrylic. Polycarbonate is tougher but more scratchable and harder to work. Acrylic will scratch too. Acrylic is easier to get in tinted form. Dark grey tint works brilliantly on boats.

Perspex can be brittle when worked. Ensure it's VERY well supported. I had a lot of luck with the triangular drill bits designed for glass and tiles. Keep acetone away from it.

On one boat I made the windows myself, on another I had a professional company do it. The price was fair for the work I know to be involved.

BTW as my boat showed fitting frameless windows can take years off the design.
 
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My acrylic windows could do with freshening up, they are 37 years old. I don't think toughened glass would be an option even if they could be bent. 3 of the Espaces which I have looked at have a crack in the port lower window, I suspect through hull flexing, perspex flexes easier than glass as far as I know, and the perspex cracked! The bigger upper windows are the ones which need to be clear for watch keeping from inside, but they are larger windows, I think I will stick to acrylic.

When I do replace them I will get covers to slow down UV degradation.
 
I had no choice .......we have a curved windscreen that was originally glass and subsequently milky perspex, at nearly 50 years old there is no chance of a cheap glass replacement....so I made a mould and bent my own perspex screen ..a bit nerve racking but it worked and I am happy with the result. professional quote £400 , material for mould and perspex cost £100....plus a lot of watching how its done on youtube!!!
 
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Freebee said:
I had no choice .......we have a curved windscreen that was originally glass and subsequently milky perspex, at nearly 50 years old there is no chance of a cheap glass replacement...
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Did you get any quotations for doing the job? Glass companies do this sort of thing all the time and I'd be surprised if it was outrageously expensive, particularly if you had the perspex one to use as a template.
 
The boat is a triana which shares the same screen as Fairey Christana's I could not hope to find the piece of glass on the shelf nor find anybody breaking a boat hence after a bit of a search and finding no convenient UK manufacturers of custom glass and being on a budget as most of us are, I did not try for a one off curved glass screen!
 
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When I did my windows a few years back, I used Perspex/Acrylic as that was used originally. The original ones(28yrs old) were quite crazed and I was recommended to replace them by the surveyor when I bought her. I used Perspex, I did not even consider glass. Still look good after 11 yrs. Incidentally, I was told that the crazing had weakened the glass considerably so I decided to try and break it and it was very difficult! Had to resort to clamping it in a vice and using a lump hammer! So it is plenty strong enough even if badly crazed.
 
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