Author Topic: Shatter proof protection for solar panels  (Read 1122 times)

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Epower

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Shatter proof protection for solar panels
« on: December 15, 2004, 02:36:10 AM »
To all who are interested. Lexan ( which is a plastic ) is the best material to protect your solar panels. Aircraft windows like the 747 are made from this material along with a thin coating of glass for scratch protection. To show how strong this stuff is, I hammered a nail through a 1/16" sheet and it did not shatter. Sercurity windows are made of the same material. I hope this helps to the ones in need...Epower
« Last Edit: December 15, 2004, 02:36:10 AM by (unknown) »

wdyasq

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Polycarbonate
« Reply #1 on: December 15, 2004, 05:27:27 AM »
The class Lexan firs in is called polycarbonate.  The generic stuff is cheaper than GE's brand usually.  And, you aren't feeding that giant corporate monster GE.  You will be feeding some other giant corporation.


Ron

« Last Edit: December 15, 2004, 05:27:27 AM by wdyasq »
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troy

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Re: Shatter proof protection for solar panels
« Reply #2 on: December 15, 2004, 05:49:38 AM »
Polycarbonate turns up in all sorts of places. In eyeglasses (I'm an optometrist) polycarb has literally ten times the shatter resistance of the other common plastic lens materials.  Football helmets are polycarb.  Safety glasses, for the most part are polyc.  In England, they call it Perspex when they put it in airplane windscreens.  Glocks, the so-called plastic guns use a polycarbonate polymer to make a metal/plastic composite structure with amazing strength and durability.


It will undoubtedly protect solar panels from hail if installed properly, but you will get ~10% loss in performance due to light transmission losses.  Also, if it's going to really protect it, it shouldn't sit right on the glass.  And since it's above the glass, then it has to be bigger than the panel itself to avoid throwing shadows from the frame onto the panel itself in morning/evening light.  So that would mean you couldn't mount the panels very close together.  Polycarb will eventually get hazy as well, though it takes several years.  That will make transmission losses worse.  There's also a maintenence issue, as polycarb scratches extremely easily if you wipe it or squeegee it very much.  So how do you clean it?  And how do you clean the underside, because that will also get dusty/dirty.


Complicated...


Best regards,


troy

« Last Edit: December 15, 2004, 05:49:38 AM by troy »

tcrenshaw

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Re: Shatter proof protection for solar panels
« Reply #3 on: December 15, 2004, 12:05:26 PM »
Problem I'm running into is that StarFire glass (shatter proof) in the 14x60" sheet I need runs $225.00 while standard glass is $96.46 each. That kind of negates my savings on building the panels myself. Those are for 3/8" thickness. I've got to find something cheaper.
« Last Edit: December 15, 2004, 12:05:26 PM by tcrenshaw »

Joel

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Re: Shatter proof protection for solar panels
« Reply #4 on: December 15, 2004, 03:37:22 PM »
For those who decide to work with polycarbonate, be aware it has a tendancy to spider-web at drill points and can be as sharp as glass when cut.  It does have some amazing elasticity (3/4" x 1" x 24" strip can be bent to touch the ends together without much damage to the glass itself) though I'm not sure if it is cost-justifiable.


Also be aware it will be more prone to certain weather and chemical damage like acid rain, bird droppings, and decomposition.


If you are just looking for something to keep your individual cells intact in the unfortunate event of hail breaking your cover plate, a simple reinforcing window film may be more worthwhile.  Look for it on automobile security/armoring sites.  Goes on like window tint but hold glass together for structural support when broken.


Joel

« Last Edit: December 15, 2004, 03:37:22 PM by Joel »

tcrenshaw

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Re: Shatter proof protection for solar panels
« Reply #5 on: December 15, 2004, 06:30:31 PM »
Thanks for the tip Joel. That reinforcing window film may just do the trick for what I'm attempting. After calling around for glass I was surprised at the quotes I was getting:


StarFire glass 3/8" thick 14"x60" safety glass is $225.00

Regular clear glass, same size $96.00

16x60 mirror (Home Depot) $22.00, along with glass cutter $8.00 and muriatic acid to remove the silvering from the mirror to make it clear glass $2.50 a gallon. Now the mirror glass is not 3/8" thick but I could use two mirrors back to back and still be half the price of the cheapest quote I got. I think I'll just stick with one though and maybe try the reinforcing film you mention.


By the way, anyone attempting to remove the silvering from a mirror with muriatic acid like I'm doing - do it in a very well ventilated area only! If in the garage, open the garage door fully! Put plastic down and put your mirror on the plastic back side up. Lay news paper or paper towel on the back of the mirror. Use a small glass jar to gently and very slowly pour the acid onto the paper. The idea here is for little or no spillage. Let the paper soak up the acid and hold it on the back of the mirror. You'll hear a sizzling, that's normal. Let old mirrors set for a half hour. New mirrors might take over an hour. Some mirrors just won't clean up well at all. Scrape off the silvering and dispose. Use rubber gloves at all times, have water handy in a bottle or by hose! Keep your nose as far from the work area as possible. Turn away to take a breath. Step outside if you feel any burning and let your nose and throat clear. Wear eye protection. Wash everything (tools, floor..etc) after use especially your hands, arms...etc This acid can be found in the pool supply area of your favorite store. Be VERY careful, it's powerful stuff.

« Last Edit: December 15, 2004, 06:30:31 PM by tcrenshaw »

ghurd

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Re: Shatter proof protection for solar panels
« Reply #6 on: December 16, 2004, 07:10:57 AM »
That got me thinking about auto windshield glass.

A 'standard' VW Beetle has a near flat windshield (the 'Super Beetle' is curved).

The auto glass place should have it flat and be able to cut it.

I don't think most people can cut the stuff themselves.

G-
« Last Edit: December 16, 2004, 07:10:57 AM by ghurd »
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tcrenshaw

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Re: Shatter proof protection for solar panels
« Reply #7 on: December 16, 2004, 09:43:06 AM »
Cutting shatter proof glass is difficult because there's actually two sheets of glass with a plastic film in between. Cutting into one side does not cause the fracture to go all the way through. Good thinking though as the old VW Wagon has perfectly flat side windows. They just aren't long enough for what I need - bummer.

« Last Edit: December 16, 2004, 09:43:06 AM by tcrenshaw »

Joel

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Re: Shatter proof protection for solar panels
« Reply #8 on: December 16, 2004, 05:03:46 PM »
If using auto glass, be sure to check the year and type.  Automobile manufacturers started using tinted glass when AC became available (around '76).  The tint is very subtile (about 92% light transmission) and may not be noticeable but should be etched on the glass.  Most auto glass cannot be cut.  It will simply crumble into a thousand pieces.  Windshield glass is the only auto glass (other than specialty bullet-proof) I know of that is layered.


Joel

« Last Edit: December 16, 2004, 05:03:46 PM by Joel »

ghurd

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Re: Shatter proof protection for solar panels
« Reply #9 on: December 16, 2004, 05:18:59 PM »
I know for certain it can be cut.  Just not by the average guy. Or me.
« Last Edit: December 16, 2004, 05:18:59 PM by ghurd »
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