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View Full Version : Lexan Windshields . . How thick?



mphatc
04-06-2009, 07:21 PM
There were several Donzi's built with free form lexan windshields . .
how thick were they . . and how tall?

The Corsican is 3/16" and fully curved. It gets it's strength from the bend.

What I will be building will be a flat form, and 11" tall . . .and I dob't know how thick I should build this . .

Mario L.


1969 Corsican
1968 Magnum 27

MOP
04-06-2009, 07:51 PM
Mario I worked with Lexan in the military back in the 50's, we had some problems with sun damage back then but I know they have added UV inhibiters. IMO 3/8" will stand up to most anything. There is a ton of info on the net, I did some poking around on the subject a few years back and was quite surprised with all the good stuff I found. Don't forget UV qualities of what you buy or it will discolor over time.

Phil

Conquistador_del_mar
04-06-2009, 07:59 PM
There were several Donzi's built with free form lexan windshields . .
how thick were they . . and how tall?

The Corsican is 3/16" and fully curved. It gets it's strength from the bend.

What I will be building will be a flat form, and 11" tall . . .and I dob't know how thick I should build this . .

Mario L.


1969 Corsican
1968 Magnum 27

At 11'' tall, I would think like Phil - 3/8" - unless you have a few support brackets at regular short spans. I had more problems with my Lexan crazing than changing colors, though. It is tough material for impacts!! Bill

zedohsix
04-07-2009, 02:01 PM
I believe there is a mar resistant lexan on the market that will resist UV and discolouration :canada:

frclarke
04-07-2009, 06:53 PM
Hi Mario:
I'm really interested in following your tech. details as you proceed. I'd like to replace my aluminium framed windshield with a more aerodynamic single piece unit.
Fred

MOP
04-07-2009, 09:13 PM
Before you spring for the $$ contact a few manufacturers not suppliers there are grades that do as good as Plexi in the sun.

Greg Guimond
01-18-2011, 04:52 PM
TTT for a Lexan update..........

What's the difference between Lexan® Polycarbonate, High Impact Acrylic, and Acrylic windshield materials?

Lexan® Polycarbonate is the tough stuff for riders that demand the best. Lexan polycarbonate with FMR hardcoat provides unbeatable strength, superior optical quality, and outstanding scratch resistance. Lexan polycarbonate with our exclusive Quantum™ coating provides scratch resistance 10X better than FMR and twice the outdoor (UV) life. Hardcoated Lexan polycarbonate is the OEM motorcycle industry standard and was proudly developed for the motorcycle industry by National Cycle, Inc.

High Impact Acrylic is a step up from regular acrylic. High impact acrylic merges the crystal clarity of acrylic with an impressive impact resistance. A standardized plastic test (IZOD test) compared standard acrylic to high impact acrylic: Standard acrylic breaks at 1.5 foot-pounds, while high impact acrylic can withstand up to 8 foot-pounds. National Cycle uses the best material for each product design and price range.

Acrylic (which includes brand names such as ICI Lucite® and Acrylite®) is good when combined with our No-Hole Ballsocket™ mounting system. Acrylic is known for its crystal clarity that stands the test of time with UV stabilization that prevents yellowing. Many years ago, during the development of the clear fairing, National Cycle found that ordinary drill mounting methods caused stress cracks and eventual breakage with acrylic shields. That’s why we developed and use our patented No-Hole Ballsocket system on all of our acrylic products.
 
Now a NEW standard has been set. Quantum™ Coated Lexan® Polycarbonate is the industry's absolute best in motorcycle windshield strength and durability. Developed for windshield use by National Cycle, Quantum coating takes motorcycle windshields a quantum leap forward in abrasion resistance and outdoor life. National Cycle applies this crystal clear, hard coating to polycarbonate material. The combined result is the strongest, most abrasion resistant windshield material available worldwide.

How Quantum™ Coating Compares

Abrasion Resistance
• Quantum coated polycarbonate has 30X the abrasion resistance of acrylic (ICI Lucite®)
• 10X the abrasion resistance of FMR coating

Crack Resistance
• Quantum coated polycarbonate is 23X better than acrylic (ICI Lucite®)
• Equal to FMR coated polycarbonate

Impact Resistance
• Quantum coated polycarbonate is 20X better than acrylic (ICI Lucite®)
• Equal to FMR coated polycarbonate

Outdoor (UV) Life
• Quantum coated polycarbonate has 2X the lifespan of FMR coated polycarbonate

mphatc
01-18-2011, 08:40 PM
Thanks Greg!

Since I wrote this I have built a Vee windshield for the Magnum 27, and cut and bent it all myself . . there's a bunch of websites and youtube videos that show you how.

I elected to use 3/8" thick acrylic, UV protected, and mount it with through holes, and rubber isolators to separate the screws from contact from the plastic.

I used a skill saw with a carbide blade to cut the material, BEFORE peeling the paper protection. This worked very well, sharp blade with many teeth .. don't recall the specifics.

Bending, so simple, use an infra red gun to measure temp during the heating process.

I should state, that the bend I needed to make was one sharp crease, a complex curve or long radius will take more then a strip heater.

Mario L.

RickSE
01-19-2011, 10:14 AM
Almost all marine windshields are made from acrylic and not polycarbonate. Acrylic is a lot easier to form and bend with out forming cracks. Lexan is good for straight sheets with out bends.

Greg Guimond
01-19-2011, 08:02 PM
Thanks Rick for the info. Curious if you are using a flat piece of Lexan can it be made to turn 90 degrees?

Greg Guimond
01-23-2011, 05:20 PM
If anyone has recently had any type of windshields fabricated using tempered glass, acrylic or lexan please drop me a pm. Thanks!

LKSD
01-24-2011, 02:38 PM
We do some of this stuff.. I just got your email.. :) I will give you a shout.. :) Jamie / Lakeside Restorations