Glass thickness for tank, used calculators getting contractions.

[Alexp08]

Hello, so this is another glass thickness post. I've looked up the calculators and I'm getting some contradictions.

First i salvaged a 30 gallon and 35 gallon aquariums for their glass i wanted to make a tank that is 3ft long, 19in wide and 16 in high. That calculates just over 47 gallons. I can either euro brace or just a simple middle brace.

Now i used the calculator and it says for a saftey factor of 3.8 i need 7mm thick glass and for 2.5 saftey i need 5mm glass.

First questions do theae round up on glass thickness? The glass i salvage is 4.76mm

Now the contradiction, i inputed the diametera for the 30 gallon aquarium i took the glass from and its saying that i need 7mm for 3.8 SF and 5mm for 2.5

So anyways I'm a little confused with these calculators, because its saying that the 30 and 35 ahould have thicker glass than it does. The 30 does not have a center brace the 35 does.

So any explication or recommendations on my build? Would i be safe with the glass thickness i have or should i scrap the project? If id be safe, what bracing should i use?

Thanks.

 

[CANAMONSTER]

That's a really small tank. You will be fine with the salvaged glass and a center brace

 

[Alexp08]

That's a really small tank. You will be fine with the salvaged glass and a center brace

Hahah to me its big! Any idea why the calculators are calling for 7mm?

 

[Drstrangelove]

You haven't given any tank dimensions. Tanks that are called "30 gallons" include at least 5 plausible and different dimensions and the range of glass thickness could vary from between 4.8mm and 7mm. I conjecture you may have one of the 5 types that uses thinner glass. (Other possibilities are that you have a reptile tank or that you have an under built tank. It might also not be a 30.)

Post the actual tank dimensions and that might answer some questions on both tanks.

Still, 4.8mm glass may work for a 16" tall tank if the glass is in good condition and if the tank is properly braced. But it works out to roughly a 2.3-2.5 safety factor (there's not calculator I have that gives it more precisely.) That's not horrible if you have good bracing and good glass. But a common standard is a 3.8 safety factor which helps offset possible glass defects, porr glass handling and sub par bracing.

Over building on the bracing 'might' make up for that, but don't take my thoughts on the matter as useful. I would ask a person who builds glass tanks for their input, since I'm just pondering the issue.

 

[Alexp08]

You haven't given any tank dimensions. Tanks that are called "30 gallons" include at least 5 plausible and different dimensions and the range of glass thickness could vary from between 4.8mm and 7mm. I conjecture you may have one of the 5 types that uses thinner glass. (Other possibilities are that you have a reptile tank or that you have an under built tank. It might also not be a 30.)

Post the actual tank dimensions and that might answer some questions.

However, 4.8mm glass may work for a 16" tall tank if the glass is in good condition and if the tank is properly braced. But it works out to roughly a 2.3-2.5 safety factor. Not horrible if you have good bracing and good glass. But a common standard is a 3.8 safety factor which helps offset possible glass defects of sub par bracing.

Over building on the bracing 'might' make up for that, but don't take my thoughts on the matter. I would ask a person who builds glass tanks for their input, since I'm just pondering the issue.

Sorry, here are the dimensions
30gallon was (36 1/4 x 12 5/8 x 16 3/4) none was tempered.
35 gallon was (36 1/4 x 12 5/8 x 19) bottom tempered and had a brace.

Just remeasured thickness of the glass the 35gallon actually has 1/32 thicker glass.

 

[Alexp08]

Sorry, here are the dimensions
30gallon was (36 1/4 x 12 5/8 x 16 3/4) none was tempered.
35 gallon was (36 1/4 x 12 5/8 x 19) bottom tempered and had a brace.

Just remeasured thickness of the glass the 35gallon actually has 1/32 thicker glass.

Actually revise that. I just reremeasured The glass and the pieces that are 1/32 smaller were the bottom and sides of the 30 gallon tank.

 

[Drstrangelove]

So, based on those dimensions, the glass sides should be 7mm on the shorter tank and 8mm on the taller tank. If these are not reptile tanks, and the glass is not tempered on the sides, then it's an interesting question of how they were used.

I think you said the glass is much thinner (4.8mm on the shorter tank.) Imo, what I said still largely applies. A tank that's 16" tall could work, if the glass is good and the bracing is good. If these were used as aquariums (to the top of the tank), then it was a risk that paid off.

You can also increase the safety margin (if you want) by keeping the tank water lower than the absolute top. E.g., at 15 inches above the bottom of the water in the tank, the safety factor on 4.8mm glass is ~2.8, but at 16.75 inches, it drops to 2.0. At 14.5", it rises to ~3.0.

 

[Alexp08]

These tanks were those store bought kind. With the brown trim. One was made by beth haha manufacturer name was removed. I have no problem making the tank smaller. I could even go to 12" high and do a nice shell dwelling cichlid

 

[Alexp08]

Okay so i went to the hardware store and got a ruler that does mm, instead of trying to convert from standard. I do believe I'm working with 6mm glass. I screwes up the measurements because they beveled the edges of tge glass so they weren't sharp. I also got abother 30 gallon for free and it has the samw glass as the 2 i tool apart and it was made by AGA.

So anyways the glass that came from the 35 is definitely 6mm and the glass from the 30 is 5-6 possibly a hair shorter than 6. So like 5.5mm if thats possible, its hard to tell the exact measurements but its atleast 5mm.

The glass from the 35 will consist of the bottom and sides. The glass from the 30 will be front and back.

Know knowing that the glass is definitely atleast 5mm with my original measurements will the new tank work?
36" long
19" wide
16" high (water will be filled to about 15")
i will probably add center bracing and bracing on both ends just for further peace of mind.

Thanks for all the help! I realize to you guys this is a small tank but i gotra start my tank building somewhere!

 

[Alexp08]

okay, another revision, its at least 5mm. its hard as hell to decipher between 5-6mm