Acrylic or polycarbonate?
#11
acrylic/plexiglass
Acrylic is harder than plexiglass but is more brittle and does not do shock well as evidenced by the video. It's like glass or hardened metal for that matter. They are both hard as can be against pressure but induce shock into the equasion and they both break. Thats where tempering comes in. Plexiglass stands up to shock very well.
#14
Polycarbonate is assuredly the best choice for a motorcycle windshield. At work we only purchase safety glasses of polycarbonate construction (Lexan) because of its superior impact resistance and protection. A friend of mine is a railroad engineer and tells me they use polycarb on their diesel locomotive windshields to protect their engineers from idiots who drop rocks and chunks of metal off overpasses onto the trains below. I bought my last windshield from National Cycle. They use polycarb. For me its a no brainer. Wouldn't think of anything else.
#15
#16
I've been a machinist for over 30 years, and have worked with both. You can put1/8 lexan in a brake press and bend it 90 deg. If you put the same in plexiglass in the press, it will shatter like glass. I make my own windshields from 3/16 lexan because I'm 6-9. The stock shields are not tall enough, and to have one custom make would cost too much. A piece of lexan 24X48 from Grainger is about 60 bux. Then I can make it wider and taller to fit me.
#17
The demo video is totally worthless, those shields are mounted with some type of fixture. Why didn't they do the test with shields mounted with the actual mounting bracket/fairing? Mainly because the shield would pop off the fairing or bend the bracket before breaking. That is a sales video, view it for what it is. The shields CB sales are approved for highway use, just like a DOT helmet (from my understanding, they are tempered on one side so as not to make sherds). Sounds like someone has a beef with CB, which is fine just don't try to make something out of nothing.
#18
There are reasons manufacturers use Acrylic over Polycarbonate for windshields:
Comparing 1/8" thick Acrylic vs Polycarbonate
Acrylic is costs less to buy & is easier to cut & hot form - Costs less = more profit
Acrylic is harder but also more prone to torsional cracking from vibration & impacts
Acrylic has to be thicker than Poly to match Poly in impact resistance
Poly requires higher skills & more steps to form correctly to maintain optical clarity
Poly cost alot more as well so theres less profit per unit
Poly is flexiable & resists torsional cracking
Poly is about 30 times more impact resistant than acrylic of the same thickness
Poly is softer than acrylic so it needs hardcoating to resist scratches.
So heres a Question ....
If you had a choice between two identical formed "re-curved" style windshields, both of the same thickness, quality, etc .... Which one would you buy ?
Acrylic for $79.00
Polycarbonate for $99.00
PS: The material formula & name "Lexan" is no longer a US Company, it was sold to SABIC of Saudi Arabia several years ago. There are other US Companies that manufacturer polycarbonate in the US.
Comparing 1/8" thick Acrylic vs Polycarbonate
Acrylic is costs less to buy & is easier to cut & hot form - Costs less = more profit
Acrylic is harder but also more prone to torsional cracking from vibration & impacts
Acrylic has to be thicker than Poly to match Poly in impact resistance
Poly requires higher skills & more steps to form correctly to maintain optical clarity
Poly cost alot more as well so theres less profit per unit
Poly is flexiable & resists torsional cracking
Poly is about 30 times more impact resistant than acrylic of the same thickness
Poly is softer than acrylic so it needs hardcoating to resist scratches.
So heres a Question ....
If you had a choice between two identical formed "re-curved" style windshields, both of the same thickness, quality, etc .... Which one would you buy ?
Acrylic for $79.00
Polycarbonate for $99.00
PS: The material formula & name "Lexan" is no longer a US Company, it was sold to SABIC of Saudi Arabia several years ago. There are other US Companies that manufacturer polycarbonate in the US.
#19
#20