What Kind Of Glass?

[dave_oddballs]

hi, in the future i plan on building a big tank, anything upto a couple of thousand gallons, well just over, 12x6x4 so the front panel would be 12 foot by 4 foot, so more realistically split into either 2 6x4 or 3 4x4, these sizes would be slightly less obviously to make up for the frame they will sit in but these would be approximate size's. what i am asking is what kind of glass would i have to use? i go onto glass supplier websites, and lucky for me there is at least 3 big glass suppliers very close to me, but i look at them sites and there is a list of all different types of glass including laminated, toughened etc. the tank would be either wood or concrete on 3 sides so its just the front panel thats glass, i will be making a frame, probably from steel which would house the glass then steel braces on top, from the top of the front panel to the back of the tank, the whole thing will be sealed with fibre glass and then on top of that would be a pond paint/sealer.
im pretty sure its going to have to be in the region of 20mm thick, i just don't know what type of glass i'd have to use!
any help or a point in the right direction would be appreciated

 

[tr0p1cal]

i thought tempered glass was the strongest stuff available, i would probably email some custom tnak makers they will give you a price and list what glass they would use, then obviously you dont buy from them but get to know what glass is best. I would have thought perhaps thicker than 20mm. my 4x2x2 is 10mil tempered glass. i guess obviously its probably safer to go for as thick as possible.

 

[VickiandKev]

I just put this into the calculator I use with an industry standard 3.8 safety factor and it's saying you need 36mm glass. That is whopping!

If you go to 3ft high, you need 23mm, then 2ft high 13mm, 18inch 8mm.

Hence why all of our tanks are low - none of the species need the height and it's cheaper on glass!!

I think you can get away with plain float glass - be careful about the toughened and tempered because I'm sure one of those shatters rather than cracks. That would be catastrophic for a fish tank - a crack gives you more time to get water and fish out, a shatter will get them out for you - straight onto the floor!

 

[dave_oddballs]

well that would be a bit of a disaster wouldn't it! so float glass doesn't shatter?
whats the crack with that laminated glass? doesn't that stuff hold together even if it breaks?
by the way im not planning on breaking it! i think it would totally depend on the cash i have at the time whether i go for 4 foot high or 3 foot high, i would prefer to go 4, not because any fish would necessarily need it but just to give more space between the top and bottom, widening my options if you will
i can see the difference in 20mm glass and 36mm glass being quite a large one!

 

[VickiandKev]

Tempered and toughened glass shatters into lots of little pieces ... but is supposed to be stronger in the first place.

Float glass cracks rather than shatters into lots of little pieces - and laminated glass shatters but holds together, essentially.

I don't like the risk with tempered/toughened glass. I don't think anyone ever intends to break their tanks, but, should it happen, I'd rather have a big crack (but the glass pieces held by the frame) than a million tiny pieces of glass, and lots of water and fish on the floor!

Laminated glass would be the best choice I think, but is probably considerably more expensive than the other options.

 

[phil140701]

Tempered and toughened glass shatters into lots of little pieces ... but is supposed to be stronger in the first place.

Float glass cracks rather than shatters into lots of little pieces - and laminated glass shatters but holds together, essentially.

I don't like the risk with tempered/toughened glass. I don't think anyone ever intends to break their tanks, but, should it happen, I'd rather have a big crack (but the glass pieces held by the frame) than a million tiny pieces of glass, and lots of water and fish on the floor!

Laminated glass would be the best choice I think, but is probably considerably more expensive than the other options.

Laminated glass is very expensive, but there is another thing to consider and thats if the edges around the glass aren't 100% perfectly sealed the water can get between the sheets of glass and cause the laminate in the middle of the 2 sheets of glass to turn opaque like what happens on old car windscreens
Phil

 

[OldMan47]

I have to agree that you will need rather thick glass, the 36mm sounds about right, for a tank that is 4 feet deep. Even my 2 foot deep tank has glass over 15mm thick and it bows a lot if I don't brace the glass with a rigid support every 2 feet along the 6 foot length. Another thought, also quite expensive, would be the glass they use for a bullet resistant window. It is very tough and about the thickness that we are talking about.

 

[atuin]

What about ditching glass at all and going for acrylic?
Lighter, stronger than glass, no problems with shattering and you can go any size you want generaly

 

[dave_oddballs]

priced up acrylic, and didn't like what they said! somewhere around £1800
i have been thinking, i could split the front 'viewing panel' into 3 and have it bow out, like half a hexagon shape, should be stronger that way and give more volume and floor space, it would have to be glass i would of thought unless i find somehwere that is half the price of that quote i got!
don't think i'll be going for bullet proof glass, bit serious that isn't it, at most i'll bang my elbow on it, not a bullet! haha.
when i come to do the tank it will have sufficient bracing, it will have numerous steel braces on top, from front to back, probably every 2-3 foot, the back and sides will more than likely be concrete block so will be more than sufficient to hold the braces too, got a lot of thinking to do, good job i've got a lot of time to do it! ha

 

[atuin]

I don't know if that 1800£ acrylic wont be cheaper option.

From what I remember max thicknes of float glass is about 19-22mm which is not enough for even 4'x4' panels
That mean you would have look go into laminated glass and that can drive price way above quoted 1800£ as you would venture into expensive world of custom non-standard sizes