# Lexan Covers?



## AaronT (Apr 26, 2004)

I've tried making acrylic covers for my emersed setups only to find out the hard way that acrylic covers warp under the heat and humidity of such setups. Would I have the same issue if I tried using Lexan?

The glass covers are fine, but the plastic would give a slightly better seal if it would just stay flat. Very Happy Not to mention the Lexan is cheaper.


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## hoppycalif (Apr 7, 2005)

Lexan has lower water absorption than acrylic does, so it would very likely not warp as much. But, my experience with Lexan, years ago, was that it turns yellowish pretty quickly. It may have been improved since I used it at work back then, so I'm not saying it wouldn't work well.


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## Blacksunshine (Aug 11, 2006)

Polycarbonate is what you want to use if you are making lids for your tank. I have a polycarb cover for my 10 gal and even over the last year it has stayed flat and clear as the day I built it. you would probably want to use no thinner then 1/8th inch. thicker if it is covering a larger area.
And I hate to have to break it to you. but polycarbonate usually runs about 2X as much as acrylic sheet.


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## rs79 (Dec 7, 2004)

Plus polycarbonate is brittle.

I've messed around with these for years. I've never found a satisfactory plastic to use as a cover. And glass can be had cheap (read "free") because it's so common.

All my covers are glass.


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## Blacksunshine (Aug 11, 2006)

huh? Polycarb isn't brittle. It has even more flexablity then regular acrylic and is like 5X stronger.


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## BryceM (Nov 6, 2005)

I've been using a 3/16" lexan cover over the lighted portion of my 46g tank for about 3 years now. To date it is crystal clear and shows no signs of warping. I've also heard that it yellows with age, but so far it's doing fine. An added advantage is that it may be cut in any desired shape without fear of introducing a crack - something that is impossible with glass. My 46 is virually sealed, with only small openings for the filtration hoses and heater cable. This allows me to keep hatchetfish and other "jumpers" without worry. 

I researched an appropriate material for a while before choosing lexan. It's pretty cheap, carried by most glass shops, has superior visual, UV, and infrared clarity as compared to glass, and is resistant to heat and chemical attack. It does scratch easily, but that comes with the territory.


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## dvanv (Nov 1, 2006)

I have had 1/4" Lexan on my 10 gallon for a year and it is doing great and still clear.


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## JG06 (Nov 5, 2006)

I worked with glass for almost a third of my life and have always used plate glass for aquarium tops. 

Depending on how large your aquarium is, you can take your exact dimensions down to your local plate glass shop and have them cut you a piece of 1/4" plate for less $$$ than you'd think. The shop should be able to put a nice smooth (safe) edge on the piece as well. If they can't, take some wet/dry sandpaper, moisten it with some water, and smooth the edges down yourself. Its not difficult as long as you're mindful not to cut yourself.

I prefer glass to lexan/acrylic/polycarbonate/etc because it won't scratch as easily and lasts forever if you don't drop it. Also, its usually pretty cheap. YMMV on cost though.


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## BryceM (Nov 6, 2005)

Glass works perfectly well as long as you have a rectangular piece. If you want to create small openings for tubes, heater cables, and such then you introduce a stress-riser that will almost always result in a crack. I've tried cutting out a small area with 1" radius fillets and it still cracks every time. Maybe there is some technique with glass that I haven't tried, but with Lexan you just put holes where you want them.


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## MNellis3023 (Oct 3, 2007)

I just purchased a top for my 46g bowfront. I got the All Glass Versa-Top, it came with a plastic hinge and the back 4'' is made of a hard plastic that is trimable for filters, tubes and what not. This was only $24 and figured I couldnt make one for cheaper


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## JG06 (Nov 5, 2006)

guaiac_boy said:


> Glass works perfectly well as long as you have a rectangular piece. If you want to create small openings for tubes, heater cables, and such then you introduce a stress-riser that will almost always result in a crack. I've tried cutting out a small area with 1" radius fillets and it still cracks every time. Maybe there is some technique with glass that I haven't tried, but with Lexan you just put holes where you want them.


There is a way to cut curves, circles, etc. in glass (I've done it). I've even cut right angles in pieces of glass but I wouldn't recommend trying it. What can be done with glass all depends on the skill of the glass cutter.

However, the best way I've found to deal with heater/filter/plumbing outlets on the rear of the aquarium is to cut the width of the top an inch short and then use either the plastic strip made to cover the rear of a strip hood or a piece of plexi. Either way allows you to cut as many holes as you like without mangling up/breaking your new strip hood.


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## blacksmith37 (Oct 10, 2006)

"Lexan" is GE's brand of polycarbonate. It is the strongest clear polymer, considered unbreakable in certain sizes. It does not have the excellent UV resistance of acrylic/plexiglas; however aquarium lights don't put out much UV. I have had no UV problems in polycarbonate in sunlight for 3+ yr.


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## Adragontattoo (Jun 3, 2007)

Aaron I can bring the Poly tops I made for my 55 using a dremel and pliers to the next Gwapa meeting or I can just explain em to you there if you want.


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