Bowing Acrylic Tank Lids ...how To Fix?

[watertown28]

The 2 used tanks that I got both did not come with covers. I went to menards and picked up some .080 acrylic and cut out some tops for them.


Well, over the past few days ( about a week ) I have noticed that the acrylic has started to "bow". How to I make stop doing that? Do I need to glue a piece along the edges to make it stronger? Or do I need to get something thicker... like .100mm acrylic? I am so sad because it started out looking nice... now it looks like you know what. I do have extra trimming left over from the cuts... so I can get some glue and put something over on top of it to make it stronger... but I hate to invest more time and work into something that will not work.

 

[DevotedToDiscus]

Not sure I understand your measurements

. Did you mean 0.080 inch? That would be 2mm. So, do you mean 0.100 inch, as that would be 2.5mm? As .100mm would as thin as paper

Also what lights are you running, as it is the heat from the lights that will cause the warping. So it would be wise not only to select the correct thickness of acrylic, but also ensure the the lights have reflector shields to help keep the heat away from the lids.

 

[watertown28]

Not sure I understand your measurements

. Did you mean 0.080 inch? That would be 2mm. So, do you mean 0.100 inch, as that would be 2.5mm? As .100mm would as thin as paper

Also what lights are you running, as it is the heat from the lights that will cause the warping. So it would be wise not only to select the correct thickness of acrylic, but also ensure the the lights have reflector shields to help keep the heat away from the lids.

Yeah not as thin as paper. These are in inches... why I do not know but that is what they use:
http/www.menards.com/main/building-materials/sheet-acrylic/clear-acrylic/080-18-x-24-clear-acrylic/p-1458025-c-7552.htm

That above link is exactly what I used. I trimmed to size for each half.

I thought about the lights being an issue for them, but I do not see how they would be the issue for a few reasons:
1) One of the tanks does NOT have a light above it. This one was also sinking in.
2) The other tank, which does have one light ... its a T8 32w bulb. Only one. It is also sitting about 3 inches above the top too. These lights do not get really all that warm to begin with... and I believe that space should allow it to be cool enough so heat should not affect it.

Edit.... being that the tank size length is 48 inches for those 2 tanks, we are talking about pieces around 24 inches long for the covers.

With those 2 reasons, I thought that maybe the stuff either was not think enough or needed to be supported. I am starting to lean on not being thick enough.

Not sure I understand your measurements

. Did you mean 0.080 inch? That would be 2mm. So, do you mean 0.100 inch, as that would be 2.5mm? As .100mm would as thin as paper

Also what lights are you running, as it is the heat from the lights that will cause the warping. So it would be wise not only to select the correct thickness of acrylic, but also ensure the the lights have reflector shields to help keep the heat away from the lids.

Yeah not as thin as paper. These are in inches... why I do not know but that is what they use:
http/www.menards.com/main/building-materials/sheet-acrylic/clear-acrylic/080-18-x-24-clear-acrylic/p-1458025-c-7552.htm

That above link is exactly what I used. I trimmed to size for each half.

I thought about the lights being an issue for them, but I do not see how they would be the issue for a few reasons:
1) One of the tanks does NOT have a light above it. This one was also sinking in.
2) The other tank, which does have one light ... its a T8 32w bulb. Only one. It is also sitting about 3 inches above the top too. These lights do not get really all that warm to begin with... and I believe that space should allow it to be cool enough so heat should not affect it.



With those 2 reasons, I thought that maybe the stuff either was not think enough or needed to be supported. I am starting to lean on not being thick enough.

each half for the tanks is around 24 inches long.

 

[paulyoung666]

no wonder it is bowing , it is only 2 mm thick , i would go for at least 4 mm if not 6 mm , that is 0.160 or 0.240" thick , i suspect no matter how you try and strengthen what you have it will be of no use .....

 

[OldMan47]

There is no way that I know of to stop that bowing. I have much the same thing on some of my tanks. It seems that the acrylic is moisture sensitive so as one side dries out the sheet bows quite a bit. I have reversed it on some pieces by simply flipping the sheet the other side up but a few days later it is just as badly bowed as it first was. If you cannot tolerate the amount of bowing involved, I would suggest that you replace the acrylic with glass. Glass will not bow due to one side drying out the way that acrylic sheet does.

 

[watertown28]

There is no way that I know of to stop that bowing. I have much the same thing on some of my tanks. It seems that the acrylic is moisture sensitive so as one side dries out the sheet bows quite a bit. I have reversed it on some pieces by simply flipping the sheet the other side up but a few days later it is just as badly bowed as it first was. If you cannot tolerate the amount of bowing involved, I would suggest that you replace the acrylic with glass. Glass will not bow due to one side drying out the way that acrylic sheet does.

I did a little test with a strip of wood and some liquid nails... along one of the edges that was bowing bad. Clamped it and let it set for about 8 hours and its back on the tank to see how it holds. If this works I will just go get a new piece and do it all over again this time with something a little more solid around the edges.

 

[watertown28]

yep I fixed the problem. So what this tells me is that it was not think enough and sturdy. I did this for all 4 pieces. They are setting just fine now. They will do for now until I get enough money to buy actual tops for them. The Bowfront is going to be the most expensive.