Crack in tank - What to do?

[JackBurton]

I've got a tank that I've had mothballed for a couple of years now. It's a 46 gallon corner tank. The tank is made up of five side panes of glass. The front pane has a small crack in the glass right at the bottom. The crack is less than an inch long and, as best as I can tell, hasn't made it through to the front of the glass yet. I'd really like to set it back up in my den.

A friend, who's into acrylic tank, mentioned that I might be able to silicon a small piece of glass right over the crack. Being that the crack is right at the bottom of the tank this might not look to unsightly.

What can I do?

 

[Fruitbat]

Short of taking the cracked pane of glass out of the aquarium and replacing it (a time-consuming chore), your friend's suggestion is about the best one. Make sure the two pieces of glass are very clean before you try to silicone them together and make sure your seal is VERY complete. You might want to take the tank outside after the silicone is dry, fill it, and let it stand for a while to see if the seal will stand the pressure of all that water. Better to do this someplace safe in case the thing springs a leak.

-Joe

 

[JackBurton]

Short of taking the cracked pane of glass out of the aquarium and replacing it (a time-consuming chore), your friend's suggestion is about the best one. Make sure the two pieces of glass are very clean before you try to silicone them together and make sure your seal is VERY complete. You might want to take the tank outside after the silicone is dry, fill it, and let it stand for a while to see if the seal will stand the pressure of all that water. Better to do this someplace safe in case the thing springs a leak.

-Joe

How think should the patch be? Same thickness as the existing glass?

 

[BASSNMAN]

You might want to use epoxy instead of silicone. It would be much stronger.

 

[mobiusnu]

How thi[ck] should the patch be? Same thickness as the existing glass?

I don't think the thickness is going to be terribly important. You'll be relying mosly on the glass's tensile strength. I would imagine that just about any reasonable chunk of glass you can find would be sufficient, assuming it's bonded well.

 

[XXFirefighter]

I wouldn't trust it at all...
Fill it with water and 150 pounds of rocks if you are gonna still use it..
See if it'll leak

 

[oldshell4481]

i would replace the side panel. cracks grow larger. epoxy (such as we use in boatbuilding class) is very strong but wont bind very well to glass. i would think that a patch would work because of the water pressure holding the patch to the side of the tank,(if done on the inside).

 

[JohnPaul]

My opinion: disaster waiting to happen. Of all of the costs and expenses that go into an aquarium, the price of the aquarium itself (i.e. just the tank) is one of the smallest parts--probably about only 20% of the total cost of setting up an aquarium, perhaps as low as 10% of the total cost if you are looking into serious lighting for a planted tank or looking into saltwater. Why risk a disaster (both financially and in terms of one huge mess in your den) over around $100?

BTW, that price is accurate...did a quick Google search, found a 46 bowfront listed for $99 here. Perhaps if you searched around you might find an even better deal.

Why is it such a risk? Because the farther down on the glass you go, the greater the force that the glass needs to withstand. A crack halfway up the glass only has half the volume of water "pushing against it" (to use a very non-engineering phrase--but one I trust makes sense!), but a crack near the bottom has nearly 100% of the volume of water pushing against it. So if your crack was near the top, I would say no problem, but at the bottom...yikes.

And I am not at all convinced the patch would work. For one, if the glass area you want to patch is bowed (as I assume it is, since you say it is on the front pane), your patch would have to be bowed as well...and bowed at the same curvature. And even then, it doesn't take into account the reality that there are a lot of things that can lead to the crack expanding besides merely water pushing against it. Fluctuations in temperature can very easily lead to the crack expanding...perhaps so little that it is not visible to the naked eye right away, but expanding nonetheless. If the tank is going to be a room temperature tank, this is not as big a concern. But if the tank is going to be tropical (heated to any temp above room temp), then there is going to be a definite temperature gradiant through the thickness of the glass. And that could lead to the glass expanding to differing degrees on either side of a crack, which means, the crack will grow.

I just think it is too big a risk to take. Considering I see in your sig you already keep a 72 bowfront up & running, you have an idea of what the expenses in this hobby are, both in set-up and in continual maintenance. Get a new tank--you'll sleep easier at night. And you won't run in a panic to your den anytime you hear a dripping noise in your house!

 

[JackBurton]

My opinion: disaster waiting to happen. Of all of the costs and expenses that go into an aquarium, the price of the aquarium itself (i.e. just the tank) is one of the smallest parts--probably about only 20% of the total cost of setting up an aquarium, perhaps as low as 10% of the total cost if you are looking into serious lighting for a planted tank or looking into saltwater. Why risk a disaster (both financially and in terms of one huge mess in your den) over around $100?

BTW, that price is accurate...did a quick Google search, found a 46 bowfront listed for $99 here. Perhaps if you searched around you might find an even better deal.

Why is it such a risk? Because the farther down on the glass you go, the greater the force that the glass needs to withstand. A crack halfway up the glass only has half the volume of water "pushing against it" (to use a very non-engineering phrase--but one I trust makes sense!), but a crack near the bottom has nearly 100% of the volume of water pushing against it. So if your crack was near the top, I would say no problem, but at the bottom...yikes.

And I am not at all convinced the patch would work. For one, if the glass area you want to patch is bowed (as I assume it is, since you say it is on the front pane), your patch would have to be bowed as well...and bowed at the same curvature. And even then, it doesn't take into account the reality that there are a lot of things that can lead to the crack expanding besides merely water pushing against it. Fluctuations in temperature can very easily lead to the crack expanding...perhaps so little that it is not visible to the naked eye right away, but expanding nonetheless. If the tank is going to be a room temperature tank, this is not as big a concern. But if the tank is going to be tropical (heated to any temp above room temp), then there is going to be a definite temperature gradiant through the thickness of the glass. And that could lead to the glass expanding to differing degrees on either side of a crack, which means, the crack will grow.

I just think it is too big a risk to take. Considering I see in your sig you already keep a 72 bowfront up & running, you have an idea of what the expenses in this hobby are, both in set-up and in continual maintenance. Get a new tank--you'll sleep easier at night. And you won't run in a panic to your den anytime you hear a dripping noise in your house!

Thanks for the replies everyone. I pretty decided to either have the pane replaced or get a new tank. The future home of this tank will be in between my two computer desks. So if the tank burst I loose several thousand dollars in equipment as well as the tank.

Thanks again everyone.

 

[hockeydude15]

i got a 1/2 inch piece of glass scraped off of the bottom corner of my tank and i glued it back on with somekind of marine epoxy. Its been about a year now and it seems to be fine.