quick question on glass

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J

js302

Candiru
MFK Member
Dec 4, 2005
651
10
48
England
hi lads.

if i'm making a tank 200cms long (this is the length of the base pane of glass) and 70cms wide, (60cms deep) and both panes of glass will be sitting on the base pane, how much space should i leave for silicone in between the panes of glass.

for example...
if the glass is 10mm thick, does this mean that the front pane should be 198 cms long if it is to be contained by the two side panes? or should it be like 197.5cms long to leave .25cms between joining panes for silicone placement?

thanks...
 
The long glass sides shouldnt sit ON the base plate, the base plate should sit BETWEEN them. This makes it a stronger build since water pressure will need to go down and then out this way. Your way only requires water to go out sideways. I will post up a picture when I can make one. Or just go to LFS or somewhere to see how larger tanks are built.

I would not allow any space for silicon but when you build the tank, do not push too hard/close as the glue will get pushed out and then suck in air (bubbles) when pressure is released.

Why dont you build a small tank first as a mock model? Its good practice and principles are exactly the same.
 
thanks!
really helps.
good idea with the mock model...
 
fishdance;923887; said:
The long glass sides shouldnt sit ON the base plate, the base plate should sit BETWEEN them. This makes it a stronger build since water pressure will need to go down and then out this way. Your way only requires water to go out sideways.

I would have to disagree with this, for the very reason you mention; pressure acting in one direction is better than in two.
Click to expand...
 
BillD,
I have posted a quick and rough diagram below of what I am trying to say. (A picture tells a thousand words as they say)

The front glass is how it should be done. Water trying to get out has to go down to get out. Since the tank is sitting on a stand, this is much harder as the water has to go through the stand too. From a construction point of view this is also better since the weight of the side glass is not on the base.... if this were the case, all the silicone glue would get squeezed out and the glue line too thin. Gluing a side panel this way also allows you a clear view of the glue line and any bubbles you dont want. Gluing the side this way also allows you to use the base as a guide. Simply press the side up firmly against the base and it will be parrallel to the other side panel (assuming your base is cut square).

The back side panel shows what you should NOT do. For water to escape it simply has to pass through a single glue line and it is out. Since the side panel is ON the base in this case, there is no guide for the side panel to be parrallel.

Anyway, this is the way glass tanks are made. If you disagree then please dont build any large aquaria since they will be unsafe. As I said before, a quick look at some already built tanks is the best bet.

Sorry for the crap diagram - I have deliberately made the base and sides the same length to illustrate more clearly my point. The base should actually be 2 glass thicknesses shorter in length than the side panels since the end panels should fit between the sides (be same width of base).
Again there are structural reasons for this but this is off topic.

tankbuild.jpg
 
Fishdance, I have several 6" long tanks (180 gals) whose sides are glued on top of the base, not like what you suggested. They've been running for several years with no leaks. I think you are mistaken on this.
 
The more critical parameter is water pressure pushing on the side glass panels themselves, not trying to leak out of the silicone beads. With this in mind, front (and back) glass panels sitting on the base will provide a stronger joint than what you propose.
 
Hartzell;952381; said:
...I have several 6' long tanks (180 gals) whose sides are glued on top of the base...
Click to expand...

:iagree: my 250g is glued on top of the base.
 
I have no wish to start an arguement so if your glass tanks are built this way and your happy then there are no dramas here. I do have a lot of experience in the aquarium industry so this is probably a case of us agreeing to disagree....

There is a photo post in the photo forum showing a new 600 gallon tank. If you look at the third photo -one with the guy inside his tank - you can see the base on this tank is beside the side panels since you can see the silicon glue line and not the edge of the base glass. He says his tank was professionally built.

http://www.monsterfishkeepers.com/forums/showthread.php?t=38313
 
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