Question about warping acruylic lids. - Pets and Animals - International Cannagraphic Magazine Forums

10-07-2009, 06:56 AM

Does anyone know why? If you are involved with keeping aquatic pets, fresh or salt water, you may have noticed at some point or another that the acrylic lids over aquariums are quite often warped. And it seems that it is a factor of age and that no acrylic lid is safe over time from the eventual back bend. I ask you this; Why? Why does acrylic bend when it is left over an aquarium for a long time?

orionsbelt · 11-12-2009, 02:18 AM

WTA,
I believe that Acrylic that sits above a tank of water(as a lid) is just absorbing more moisture on the side facing the water than the other facing air. As it absorbs moisture it expands more on the one side than the other creating the warp.

ROJO145 · 11-12-2009, 02:58 AM

Gravity man,its no mystery.Shits always around pullin things down!!
Acrylic dont absorb no water.

11-12-2009, 04:44 PM

yup gravity ancd the heat from yer lights is causing the warpage, Just flip it over and roll on!
FYI, acrylic does absorb water, just not much.

Quoted from another site i frequent, by a respected acrylic fabricator..

"So why doesn't acrylic absorb water? Because you say so? Want to put some money on that?

Most acrylics, and for that matter, most plastics & rubbers, are porous and expand underwater, many will suck up about 1% of their weight in water in just 24 hours. If you weigh a piece of acrylic before and after soaking it in water for say... a few months, you might be shocked how much heavier it gets. There are some acrylics that have their surfaces 'sealed'... scratch resistant and chemical resistant ones... they are almost impossible to bond with weld-on because of this. But the rest... cast, extruded, etc... they suck up some water. In fact, there have been patents and research devoted to the formulation of acrylics sheets that are 'low moisture absorbing'. FWIW, acrylic is MADE from water.

This is why acrylics aren't approved for use around food by the FDA. PE is used instead because its 'safe'. This special “safe” quality comes from the fact that PE is a CLOSED CELL material. That means it doesn’t absorb any water. And because it doesn’t absorb any water, it floats (unlike acrylic which will quickly sink to the bottom). That’s why polyethylene is also commonly used to make kayaks and other things that float as well as tarps and pool covers.

I suppose you dont believe that CO2 cant pass through regular airline hose either... "

10-07-2009, 06:56 AM	#1
WTA Guest Posts: n/a	Question about warping acruylic lids. Does anyone know why? If you are involved with keeping aquatic pets, fresh or salt water, you may have noticed at some point or another that the acrylic lids over aquariums are quite often warped. And it seems that it is a factor of age and that no acrylic lid is safe over time from the eventual back bend. I ask you this; Why? Why does acrylic bend when it is left over an aquarium for a long time?
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11-12-2009, 02:18 AM	#2
orionsbelt New Member Join Date: Aug 2009 Posts: 9	WTA, I believe that Acrylic that sits above a tank of water(as a lid) is just absorbing more moisture on the side facing the water than the other facing air. As it absorbs moisture it expands more on the one side than the other creating the warp.
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11-12-2009, 02:58 AM	#3
ROJO145 Banned Join Date: Dec 2008 Location: On the Hill Posts: 1,554	Gravity man,its no mystery.Shits always around pullin things down!! Acrylic dont absorb no water.
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11-12-2009, 04:44 PM	#4
Rysam Guest Posts: n/a	yup gravity ancd the heat from yer lights is causing the warpage, Just flip it over and roll on! FYI, acrylic does absorb water, just not much. Quoted from another site i frequent, by a respected acrylic fabricator.. "So why doesn't acrylic absorb water? Because you say so? Want to put some money on that? Most acrylics, and for that matter, most plastics & rubbers, are porous and expand underwater, many will suck up about 1% of their weight in water in just 24 hours. If you weigh a piece of acrylic before and after soaking it in water for say... a few months, you might be shocked how much heavier it gets. There are some acrylics that have their surfaces 'sealed'... scratch resistant and chemical resistant ones... they are almost impossible to bond with weld-on because of this. But the rest... cast, extruded, etc... they suck up some water. In fact, there have been patents and research devoted to the formulation of acrylics sheets that are 'low moisture absorbing'. FWIW, acrylic is MADE from water. This is why acrylics aren't approved for use around food by the FDA. PE is used instead because its 'safe'. This special “safe” quality comes from the fact that PE is a CLOSED CELL material. That means it doesn’t absorb any water. And because it doesn’t absorb any water, it floats (unlike acrylic which will quickly sink to the bottom). That’s why polyethylene is also commonly used to make kayaks and other things that float as well as tarps and pool covers. I suppose you dont believe that CO2 cant pass through regular airline hose either... "
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