Best prop response I got this year

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Originally Posted by ravensmoon

Yes Poly is WAY stronger, doesn't crack, and mills much easier, but it actually scratches WAY more than the Acrylic and it also bows a lot when laid flat (which is one of the reasons it is so strong)... Unfortunately when I did this effect a few years ago I went with the polycarbonate for strength and it scratched very easily. this year I researched to find something that wouldn't scratch or bow (basically went to a large plastic manufacture in the area where I bought the stuff and told them what I was doing) and the scratch resistant Poly was 3x the price of normal poly. So I just got a 3/4" acrylic which was about 1/3 the price of normal poly, and was plenty strong enough for what I was doing. It held up much better and the scratches were pretty much unnoticeable.

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Awesome- someone else did the guinea pig thing for us! Your info is good to know!

I'm wondering if when you spoke to the manufacturer- did the question of information about load rating come up? For instance- 3/4" plexi is good for your application but at what weight and how much longer could it be made and still support the same weight proportionately?

Steel beam load calculators are easy to find, but I doubt such a thing exists for plexi. Short of hiring an engineer to figure it out I'm not sure you could conjure the answer without expensive trial and error...

Thanks again for the info!

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Originally Posted by zombietoxin

Awesome- someone else did the guinea pig thing for us! Your info is good to know!

I'm wondering if when you spoke to the manufacturer- did the question of information about load rating come up? For instance- 3/4" plexi is good for your application but at what weight and how much longer could it be made and still support the same weight proportionately?

Steel beam load calculators are easy to find, but I doubt such a thing exists for plexi. Short of hiring an engineer to figure it out I'm not sure you could conjure the answer without expensive trial and error...

Thanks again for the info!

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No specifics but it was a 4' x 4' span and at most you could only have 1000 pounds on it at one time (6 people+-) that being said most custom aquariums are made from acrylic and that is only 1 foot of water over the 16 sq ft. so I don't think it even begins to come close to its breaking weight.

you could use thin layer of plexi over lexan... if wanting to prevent scratching lexan, not sure how this would work/look overall ...just wanted to throw it out there

There is a way to calculate the load rating of Lexan. Ready?

The tensile strength is 9860psi while the tensile strength at yield is 899. Elongation at break is 130 percent, while at yield is it is 7 percent. The flex yield strength is 13900psi. Its falling dart impact is 125 feet per pound and notched Izod impact is 15 feet per pound.

Or you can ask an engineer ;-)

Found this info by the way on e-How. By the way, I buy Lexan at Lowes Hardware, although I don't remember if they had really big sheets. I use them for ticket windows, etc. I also use plexiglass for some applications. When mounting, they make a special washer with rubber that goes into the hole and around the hole (like a grommet almost). I get those at Ace Hardware. Keeps the stuff from cracking when I screw them down.