Thats a serious piece of glass! I guess you have a very tall tank. Great to know that I can stop worrying about distortion in laminated glass
Plywood tank 800 gallon, choice of glass not so simple
- Thread starter Jon_DK
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Thanks Midwater. I guess I could also use 3/4" tempered
3/4 tempered glass is easy strong enough, yes it's very green (big ponds tanks use it often) ,(5/8 regular no)(3/4 regular no), yes flip it in every direction to see if it's fits differently, very rare not perfectly flat on the edges(factory knows if its pefect or not), 1/2" would even work with very slight flexing of the edges under water pressure of 700 gallon 
my two cents
cheers ,
my two centscheers ,
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This week, I will order my glass, but I have not fully decided yet.
I think going for laminated tempered glass is the safest choice. Unfortunately, I can only get this option with PVB interlayer foil (no SGP option available). Besides the risk of swelling and delamination, PVB can also yellow over time (mostly a problem if exposed to sunlight). So, for PVB, I will certainly have the extra task of finding a way to seal the edges with something that doesn’t damage the sensitive foil.
3/4" tempered glass is simpler due to the lack of interlayer foil. I found out that some companies offer a "heat-soak" test. This test heats the finished tempered glass to a high temperature for several hours. This will, in most cases, expose any faults due to nickel sulphide contamination, which is responsible for local tensions that could result in sudden failure. I read somewhere that unprovoked tempered glass explosions happen in 4 out of 1000 pieces of glass. This is when the glass is correctly set up. It's not a big risk but still a risk. The heat-soak test is recommended for tempered glass used in situations where failure could compromise personal safety.
Thanks, everyone, for your valuable help – it's highly appreciated.
I think going for laminated tempered glass is the safest choice. Unfortunately, I can only get this option with PVB interlayer foil (no SGP option available). Besides the risk of swelling and delamination, PVB can also yellow over time (mostly a problem if exposed to sunlight). So, for PVB, I will certainly have the extra task of finding a way to seal the edges with something that doesn’t damage the sensitive foil.
3/4" tempered glass is simpler due to the lack of interlayer foil. I found out that some companies offer a "heat-soak" test. This test heats the finished tempered glass to a high temperature for several hours. This will, in most cases, expose any faults due to nickel sulphide contamination, which is responsible for local tensions that could result in sudden failure. I read somewhere that unprovoked tempered glass explosions happen in 4 out of 1000 pieces of glass. This is when the glass is correctly set up. It's not a big risk but still a risk. The heat-soak test is recommended for tempered glass used in situations where failure could compromise personal safety.
Thanks, everyone, for your valuable help – it's highly appreciated.
3/4 inch tempered glass is strong enough but tempered glass flexes far more than float glass.This can be a bit concerning for some. It might be best for you to look at some similar sized tanks first?
In an all glass aquarium, the other adjacent perpendicular glass pieces act as significant braces to stiffen each panel.
If you have young kids, overly safety concious, expensive floor coverings - furniture etc then laminate is better. There is a reasob why public and commercial tanks use laminate. And there are other factors besides what is structurally adequate. In commercial builds, they would use 3/4 tempered glass each side if 3/4 was the minimum.
Looking ahead, you may want a bigger tank later so perhaps you can buy an oversized piece now? Sometimes its cheaper to get thicker glass than you requure if that thickness is commonly manufactured in volume.
All tempered glass gets heated and cooled which creates the strength (and wavy cross section) so I doubt a heat stress test would reveal anything.
Going for thicker glass may have hidden costs to consider. Transport, construction (I needed a small crane and an edge grabber) and even simple magnetic algae scrubbers - mine were $1000 a set from mighty magnet.
In an all glass aquarium, the other adjacent perpendicular glass pieces act as significant braces to stiffen each panel.
If you have young kids, overly safety concious, expensive floor coverings - furniture etc then laminate is better. There is a reasob why public and commercial tanks use laminate. And there are other factors besides what is structurally adequate. In commercial builds, they would use 3/4 tempered glass each side if 3/4 was the minimum.
Looking ahead, you may want a bigger tank later so perhaps you can buy an oversized piece now? Sometimes its cheaper to get thicker glass than you requure if that thickness is commonly manufactured in volume.
All tempered glass gets heated and cooled which creates the strength (and wavy cross section) so I doubt a heat stress test would reveal anything.
Going for thicker glass may have hidden costs to consider. Transport, construction (I needed a small crane and an edge grabber) and even simple magnetic algae scrubbers - mine were $1000 a set from mighty magnet.
Hi there do you know how the tensile strength is calculated for laminated glass? I mean for example a 6mm+6mm both tempered glass laminated is comparable in tensile strength to a 12mm tempered glass? I try so hard to find information regarding this all over the internet and no source can confirm it
Unless your using interlayer foil like SGP then 6mm + laminate + 6mm would have the structural equivalent of 6mm glass. EVA slightly stronger and more water resistant than PVB but the laminate isn't intended for structural strength. The thickness of laminate layer is related to tear resistance - assuming the glass will fail.
From what i tried to read from the internet, even SGP have tensile strength of around 35n/mm2 while tempered glass seem to be around 100-200n/mm2 so even with SGP film how would we know what thickness of glass is sufficient because seem like laminated does not help? 19mm tempered+1.52mm SGP+19mm tempered would have tensile strength of just 19mm tempered? so does it mean that glass can never be use to build aquarium deeper than 150cm roughly? because with safety factor of 3.8 thats around the maximum 19mm glass can handle if i remember correctly.
SGP is a structural laminate.
It sounds like your confusing tear strength (adhesion) with rigidity (hardness). You can manufacture triple and quadruple layer laminate as well.
I've built glass tanks to 3m deep and know of some glass tanks 5m deep but you should be consulting a structural engineer with real world experience (as I do) for tanks 2m or more depth. There is a reason why your not able to find this information freely available on the internet and I would not be trusting information offered on an amateur aquarium forum including this post. The 3.8 safety factor you mention for example is a joke for larger tanks.
It sounds like your confusing tear strength (adhesion) with rigidity (hardness). You can manufacture triple and quadruple layer laminate as well.
I've built glass tanks to 3m deep and know of some glass tanks 5m deep but you should be consulting a structural engineer with real world experience (as I do) for tanks 2m or more depth. There is a reason why your not able to find this information freely available on the internet and I would not be trusting information offered on an amateur aquarium forum including this post. The 3.8 safety factor you mention for example is a joke for larger tanks.
