Glass bottom safety factor

[Jade5051]

Can someone please help me or point me in the right direction? I'm trying to calculate the thickness for a 3.8 safety factor on the bottom of a 28x28x17 aquarium. I'm using 0.5" glass for the sides and need to cut a 28x28 bottom but I don't know how thick the bottom needs to be. I've been looking on the interweb for over an hour now. :headwally:

 

[Jade5051]

Finally found a calculator that says 8.5mm which would be 3/8" glass. I'd like to not have 55 gallons of water on the floor could anyone please reply? Does that sound right? I was going to do rimless if that makes a difference.

 

[mcgyvr]

[MENTION=74862]Jade5051[/MENTION]
The answer depends on how the bottom is supported..

 

[lapin]

When in doubt and not being a seasoned builder I would error on the side of thicker.

Disclaimer:
Most of my glass tank experience is with the old metaframe slate bottom tanks.

 

[oreo57]

Finally found a calculator that says 8.5mm which would be 3/8" glass. I'd like to not have 55 gallons of water on the floor could anyone please reply? Does that sound right? I was going to do rimless if that makes a difference.

3/8 = .375 = 9.5mm approx.
Should be thick enough..

Calc I play w/ given your dimensions (17 is DEPTH right) would give 3/8" bottom a safety factor of 4.8...


side glass needs to be only 6.4mm...283" thick.

If you actually go 1/2 sides just do 1/2 bottom..
Or all 3/8" glass.

l and width can't be equal thus the discrepancy ..and also rounded a bit.

 

[mcgyvr]

You want more than a 3.8 safety factor on a rimless tank..
Often they use near double (7-7.6) or more for rimless..

 

[oreo57]

You want more than a 3.8 safety factor on a rimless tank..
Often they use near double (7-7.6) or more for rimless..

AFAICT those calcs assume "free standing" i.e rimless..
1/2 thick glass bottom on a 50gal tank..for a factor of 7+ btw.

The calculator calculates the bending of a glass pane with the forces that would be exerted by water on the pane if it was freestanding (supported on 4 corners, but not fixed).

https://www.marineaquariumsa.com/th...thickness-on-a-brace-less-rimless-tank.48280/


Calc maker..and good discussion..


I have no problems w/ "overbuilding" anything..and would rarely settle for "minimum" thickness but don't see 3.6 as minimum..

You could check w/ Glasscages to see their glass thickness. They have a close tank size:

40 Square (Rimless) 24 x 24 x 16 tall

 

[Jade5051]

The reason I'm using 1/2" glass for the sides is because it's scrap glass from another tank that broke. I just need a bottom and I have a tank.

 

[oreo57]

The reason I'm using 1/2" glass for the sides is because it's scrap glass from another tank that broke. I just need a bottom and I have a tank.

I get stuck in my head...

Using thinner glass for the bottom (regardless of safety factor) is just psychologically unacceptable..

14.8 (sides) and 8.5 (bottom) safety factors for 1/2 all around..

1/4" (6mm) ..nope
5/16" (8mm) It is not common in US. nope..
3/8" (10mm) pick one
1/2" (12mm) pick one

 

[H2oGarden]

3/8 if supported, 1/2 if not supported.