Fixing A Cracked Tank

[nick1200]

So im trying to add a plane of glass over the top of a crack in my tank.But the crack is right near the front of the tank and the new plane of glass will come up to the front of the tank. Im just wondering if two different types of silicone will go together ?
 
Here is the plane of glass ontop of the crack.
 
 

 
Has you can see the black silicone goes under the new plane so if i silicone the plane down the new silicone will go on the black silicone going around the tank.
Is this a problem or ? I have read some were that you can not put old and new silicone together. But to get rid of the old silicone i would have to reseal the whole tank...
 
Also the feet on the glass will come off be for anyone says...

 

[Zikofski]

i dont see a problem with this altho i would prefer the glass to be the same thickness as to the original, also your question about old silicon on new should not be a problem as we discused in chat, but i would allow extra time to cure, 1 to 2 weeks should be enough hope this thick's the problem enjoy

 

[nick1200]

i dont see a problem with this altho i would prefer the glass to be the same thickness as to the original, also your question about old silicon on new should not be a problem as we discused in chat, but i would allow extra time to cure, 1 to 2 weeks should be enough

hope this thick's the problem enjoy

I understand that would stop the leaking but what about the pressure on the crack ? Won;t the crack get bigger ?

 

[Zikofski]

okay my understanding could be completely wrong, because the plane with the crack in it is the bottom plane and is still in contact with the stand this will still take all the pressure no matter how many pieces of glass you put onto, i would probably glue the whole crack without the piece of glass as the picture you showed me looked quite small of a crack just make sure there is enough support under the tank

 

[nick1200]

okay my understanding could be completely wrong, because the plane with the crack in it is the bottom plane and is still in contact with the stand this will still take all the pressure no matter how many pieces of glass you put onto, i would probably glue the whole crack without the piece of glass as the picture you showed me looked quite small of a crack just make sure there is enough support under the tank

 
 
I thought id post another image
 
Here is the crack which i am on about when i first got it.

 
 
And here it is now two weeks after
 

 
I have edited it to show that it goes around and you can see that  i have siliconed the crack but only have of the silicon has stuck the other have has gone and have left half of the crack vulnerable
 
Here is some pics of it be for it got to me ( with no crack )
 

 

 
No damage to the front of the tank be for it was moved to me  ( damage posted above after i got it )

 

[bodge99]

Hello,
 
You are asking for problems here....
 
I've seen cracks like this propagate further after a considerable period of time had passed (more than 2 years).
Also, I would not recommend appying new silicone over old.. It will not adhere properly or last as long as you hope..
 
Tank glass is under considerable stress when the tank is full of water.. Why risk a disaster for the sake of a little more work?
 
I'd strongly recommend a complete tear down and rebuild with the damaged glass replaced..
 
One tip... If you do decide to tear down and rebuild, polish the glass edges before reassembly (oilstone and lubricant **carefully**).
 
Just my 2p worth.
 
Bodge99.