Perspex / acrylic?

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Novice21

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I've just been in to a shop to ask about them making some new perspex windows for the coachroof. The chap in the shop said that perspex is a trade-mark and they do acrylic, which is the same material under a different name... is this right, or is it just a line to get my money?!
 
Good. Just thought I'd check.

Just for the record, the word 'PERSPEX' is in big letters under the name of the shop (along with BRASS, COPPER...)!
 
Having said all that, Perspex or any acrylic is not ideal for boat windows as it is not very strong and crazes in a relatively short time. Suggest you use a polycarbonate - generic name but available from the major manufacturers. If you have a pattern then the best source would be a sign maker as they could cut them out, radius the edges and drill the clearance holes for fastenings much better than DIY (speaking from experience here!). There are some firms who specialise in this type of work and advertise in the classified section of PBO.
 
Ok, just wanted to be sure before I handed over the dosh coz I'm a bit of an ignoramous, so I feel like a target! I'll get the windows off at the weekend, and get organised. Thanks again /forums/images/graemlins/smile.gif
 
Because acrylic is more resistant to scratching than polycarbonate. Acrylic can however craze if exposed to certain solvents or stress - e.g. bending round sharper than the gentlest of curves.
 
Polycarbonate is a better material for boat windows as it is stronger - it is the same material that they make bullet proof glass from. However, perspex (acylic) does have a harder external surface so is less susceptible to scratching.

You can get polycarbonate with a harder outside surface (macrylon If I Recall correctly.) It does bend more than perspex (which is why it is better as a window).

both are susceptible to UV ageing so do replace before they get too brittle.
 
We use "Plexiglass Resist 65" at work for an application that requires good impact resistance AND a hard wearing surface. It's an "impact modified" acrylic so you're supposed to get the best of both worlds. The only thing is, we don't need good UV resistance because it's not outdoors, but the datasheet does claim excellent UV stability. It has a Charpy impact strength of 65kJ/m^2 which, to give some comparisons, ordinary acrylic is about 15 and polycarbonate is about 100. They also do a "Resist 75" and a "Resist 100" - which should be about the same as polycarbonate.
 
All perfectly true old bean. Just wanted someone else to do the arguing as I have taken vows to be nice!
I would add that PC without a toughened outer skin is very soft and will soon scratch. With a toughened outer skin is is expensive. Acrylic is cheap and cheerful and quite adequate while being fairly scratch resistant. After a while both will suffer from extreme UV exposure, Acrylic more than PC. Acrylic is however easy to replace and as I said, cheap.
 
Wouldn't disagree with the above comments. If anyone does fancy cutting new windows themselves, though, it's not that hard.

When I did my side windows last year (clear cast acrylic) I ordered nearest cut-to-size rectangles very cheaply from The Plastic Shop (who also have an excellent series of technical, cutting and working info on the site) and then just cut the corner radii and front and rear 'slopes' with a jigsaw with fine toothed plastics blade.

Cost was a fraction of Eagle Boat Windows quote, and about half the cost of fully-cut replacements from local perspex merchants.
 
I installed polycarbonate windows four years ago. Polycarbonate is very liable to scratching, just wiping with a dry cloth will leave micro scratches. We have never cleaned our windows except by pressure hose. Polycarbonate is much stronger than acrylic and does not craze (hence my decision to use it). After four years the windows are still very clear, however there are a few scratches where the windows have been 'kicked' when out sailing.
 
Did you say cheep
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/forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
 
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