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Re polycabonate sheet.


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I need to replace the  wind-screen of my Thruster which is 1.5mm polycabonte sheet. Trouble is, I can only get 1.0mm locally. Will this be strong enough? Being formed into a continuous curve, I think it might be but would like a more experienced opinion if any-one is up to it.

 

Thanks in advance,  DP.

 

 

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I don't know the answer, but compared to 1.0 mm sheet, 1.5 mm sheet will be about 3.3 times stronger in bending and 5 times stiffer.

 

 

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I think that 2mm sheet is too heavy (add lightness).  It could stress crack when pulled around.  Try to source 1.5, otherwise, 1mm might do. 

 

 

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My local supplier goes from 1mm to 3mm and that's way too thick. As for weight, I've already added so much I'm beginning to wonder if I'll actually get of the ground. Mind you, I had to put another hole in my belt last week. Not saying I'm loosing weight, it's just shifted some-where else.

 

 

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Savannah is 1.5mm

 

If this is indeed 3 times stronger and 5 times stiffer then 1.0mm, it would seem worth going the extra mile for?

 

 

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Savannah is 1.5mmIf this is indeed 3 times stronger and 5 times stiffer then 1.0mm, it would seem worth going the extra mile for?

Oops! I should have said 2.3 times stronger and 3.3 times stiffer. Apologies all. However the difference is still significant given the small increase in thickness. Can’t go back and edit my previous post unfortunately.

 

 

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  • 2 weeks later...

The good new, DP, is that polycarbonate is getting cheaper. The price halved in the last ten years, presumably because it's now sourced from China. That means is cheaper to replace your screen, which you need to do much more often than with acrylic (Perspex) which is harder, less scratch resistant, but more easily cracked.

 

I'd like to see how thick our screens need to be; has anyone whacked a curved sheet of poly with a defrosted chook travelling at 90knots?

 

 

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The good new, DP, is that polycarbonate is getting cheaper. The price halved in the last ten years, presumably because it's now sourced from China. That means is cheaper to replace your screen, which you need to do much more often than with acrylic (Perspex) which is harder, less scratch resistant, but more easily cracked.I'd like to see how thick our screens need to be; has anyone whacked a curved sheet of poly with a defrosted chook travelling at 90knots?

No, but big bird's go thru a cherrokee screen which is about 5mm

 

 

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No, but big bird's go thru a cherrokee screen which is about 5mm

I presume the Cherokee screen is (brittle) acrylic. I guess speed is a major factor. Even the incredibly sloping

F-111 screen couldn't protect its crew from bird strike.

 

 

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It's great stuff, Gareth. I feel much safer behind polycarbonate than acrylic. My motorcycle helmet visor was once hit by a golf ball-sized rock thrown up by an oncoming vehicle. Impact speed must have approached 200k, but the curved lexan protected my features by bending in enough to whack my nose.

 

I've driven nails thru it, bent it in the vice with a hammer and made lots of items from off cuts. Like some grades of aluminium, lexan will crack if bend at too tight a radius. It's also hygrostatic- absorbs moisture- which leads to problems if you're dumb enough to try heat-bending it as I did. The moisture eventually boils, exploding the lexan sheet into a blistered mess. It can be forced into complex forms if heated beyond 130C (from memory), but first the water has to be dried out by oven-curing at 60C for 24hrs.

 

 

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I used lexan for the screen and perspex/ acrylic for my canopy, so that I have a chance of smashing my way out if I prang it. I also cut slots to all mounting holes to make it easier to break out.

 

 

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