Building a 48x48 tank
- Thread starter renisel
- Start date
renisel
Member
According to those calculators, no 55 or 75 gallon tank with 1/4" glass should be on the market--but they are. So it would seem that they are oversimplifying things and don't really offer an answer to my question.
I guess what I should have asked was:
If the front and back panes on a 55 are fine for that application, is there any good reason why they wouldn't be OK to be used as the sides, front and back of a 4'x4' tank?
yes lots. When you add that much water to that much size the pressure changes. Think as water put into something as pushing against the outside. You increase that size from 12" to 48" your pressure completely changes. I would think it would hold water for about 30 seconds then bust at every seem. Also the bottom plate is not strong enough to handle all that water pushing downward.
renisel
Member
The pressure is a function of the depth and nothing else (well, ambient air pressure too, but that's not a variable here). The only thing I can think of that would come into play is the area across which the adhesive is applied. You have exactly the same amount of force pushing against the front and back panes, but the silocone attaching two panes will have more force against the side panes that it has to counteract. But, as far as I know, the silicone is not generally being pushed anywhere near its limit.
Yes i agree with you that pressure is a function of depth but by you saying that, you could build a 100ft tank by 12" high and a 12ft tank by 12" out of the same glass and i presume you wouldnt think of doing that
Rancherlee
New member
As long as proper bracing is supplied I don't see an issue. You would need either a BEEFY bottom pane or excellent bracing for the bottom. Pressure on the front/back panels, as other have stated, is identical wither the tank is set up as a 55 gallon OR a 190 gallon cube. As I've had every 55 gallon tank I've owned bust the plastic center brace I'd be looking to build a pretty beefy upper and lower rim with a strong X brace. I know the thoughts crossed my mind to to build a 4x6 tank out of my 125 gallon for a peninsula tank in my basement. Haven't priced a 4x6 sheet of glass for the bottom pain yet though......... would be a 315 gallon tank!
Maybe im missing something, i understand force is a relation of height P=(rho)gh, and pressure= F/A so that is why you need a beefier bottom. But wouldnt by extending the side braces longer, wouldnt you affect the integrity of the other panes by adding more force to those sides. Thus bowing all the sides which in turn weakens the other sides?
You should have at least 5/8" glass on the bottom of that tank and at least 1/2" for the sides. The glass used in many 55 gal tanks is usually thinner than it should be as it is. Why be cheap and take the chance? Just add up the weight in water from those dimensions, plus sand, rocks, etc., and it SHOULD start to make sense.
codyreef29
New member
going with acrilic would probably be your best bet. When your looking at bracing and having thin sides acrilic is glued together bracing a 55 gallon side with silicone?? Not gonna work.
Using acrilic to make a large 8 meaning bracing along all the sides and one across the center. Also adding glass at the edges bottom lower outter around the top and maybe 3 or 4 braces along the top. You will probably be spending more money on glass to brace it then to buy the correct thickness of glass. getting qoutes from custom tank builder and seeing what they can do will be your best cheapest and warranted or long lasting choice.
Using acrilic to make a large 8 meaning bracing along all the sides and one across the center. Also adding glass at the edges bottom lower outter around the top and maybe 3 or 4 braces along the top. You will probably be spending more money on glass to brace it then to buy the correct thickness of glass. getting qoutes from custom tank builder and seeing what they can do will be your best cheapest and warranted or long lasting choice.
tgunn
Active member
It will also be very difficult to take apart the tanks made from 1/4" glass. I took me many many evenings to rip apart a 100g sump built from 3/8" glass, and I still caused some chips along the edges here and there.
One apart I used a single sheet of the 3/8" glass to make a nano tank, and it took many many many hours to scrape the old silicone off well enough to build the new tank. Even then I don't know if I got it clean enough to use in a high pressure application.
One apart I used a single sheet of the 3/8" glass to make a nano tank, and it took many many many hours to scrape the old silicone off well enough to build the new tank. Even then I don't know if I got it clean enough to use in a high pressure application.
Euler Kernighan
The "DIY Guy"
you can use 10mm or 12mm thick. I work in this business :thumbsup:
I have taken apart two 55 gallon tanks for this same project. The glass I got out of them is 3/8" thick and I'm thinking they won't work, to thin. I did price some 1/2" glass from glass cages pre cut and edges cleaned that was really reasonable surprisingly. I gave up on trying to build one and headed to pick up an acrylic 48x48 tomorrow
The length of the side matters. Think of a beam with supports on each end. The longer the beam, the stronger it has to be to support the load. In this case the load is water pressure per unit length. (the pressure is a function of depth, gravity, and the density of water)
The bending stress is a function of the square of the length and the deflection is a function of the 4th power of the length, IIRC.
Since the side wall is continually attached to the bottom, the beam analogy doesn't hold 100%, but it is similar.
The bending stress is a function of the square of the length and the deflection is a function of the 4th power of the length, IIRC.
Since the side wall is continually attached to the bottom, the beam analogy doesn't hold 100%, but it is similar.
rwb500
Active member
what we're discussing is not the length of the side in question, but the length of the other two sides. obviously it is impossible to cannibalize panes to make panes longer than the original.
uncleof6
Active member
Most 55s are tempered, and that makes a difference. A 75 gallon tank with 6mm glass will most certainly be tempered, or the water would be outside the tank. (depending on dimensions.) One cannot look at a manufactured tank, that are often horribly under built (look at the cube tanks that use 6mm glass, and are popping seams with some regularity,) and expect to learn anything about building tanks.
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Tank building is a very highly specialized craft that requires some engineering skills, knowledge of material strength (in a given and specific context) and water pressure; knowledge of what "strength" is important, and what "strength" is irrelevant. For instance, the tensile strength of silicone is irrelevant: because it is not the weakest link in the chain.
After building tanks for better than 20 years, I (and many other professionals) have come to the conclusion that tank building is not something that can be taught via the web, whether it be videos on youtube (the worst place to get information put out by self-promoting diyers that are lucky they don't need liability insurance) or by reading posts in a forum. The best that can be done is hopefully keep people out of very serious trouble, but the outcome of the build still has so many variables attached to it, it is impossible to predict it.
In most all cases, a person asking questions concerning glass thickness should not be building a tank, and it would be far better and safer to buy a tank of similar dimensions. Depending on where the tank is purchased, it could very well be under built, (production tanks always are,) but at least there is a warranty (if you do what they tell you to) to cover the catastrophic damage if the tank decides to self-destruct.
For the first tank mentioned in this thread:
15mm sides and ~ 19mm bottom for rimless, internal euro-braced bottom can be 15mm. A professional could build this with 12mm, but an amateur should not even consider it. The extra 3mm just might save the day, if other constructions methods fall short, and it is highly likely they will.
10mm is the thinnest glass that should be used, and that would need a full rim; 12mm running next with a euro-brace. (top and bottom.)
This is not a contest of cost, weight, or availability—it is about keeping the water inside the tank. In terms of cost it will most often cost less to buy a tank, or have one built for you.
karimwassef
Active member
What's a ghost overflow?
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