Custom built tank question

[RyanM]

I am planning on building a 48"x 24" x 24" Glass tank and just wanted to check my plans out with anyone with any tank building experience before I have the glass cut. (120 Gallon) The front is 3/8" Starfire.

The glass will be 3/8" thick bottom and sides.
The top brace will be 1/4" x 2" all the way around with a 2" center brace. I am toying with the idea of taking a full size sheet of 1/4" and cutting out the 2 centers making the top brace all one piece. It seems to me that it would be stronger than individual pieces.

Questions,

I read on garf that when building a tank that the sides should rap around the botton rather than sit on it. and that the bottom should be 1/4" up. I understand that the bottom if not sitting on somthing perfectly flat would crack the bottom if the tank is resting on it but I cant see how all that water and rock and sand would not just smash the silicon and the bottom would drop and leak from the weight.

Whats right? Build the tank with the sides resting on the bottom and make sure the stand is perfectly flat or build it like garf says and rap the sides with the bottom lifted 1/4".

I dont know, I just dont like the idea of the bottom being suspended in mid air being held up with nothing but a bead of silicon to hold all that weight.


Second question is the top bracing. Would I be better of going 1/4" acrylic or should I stay with glass and am I over doing it by trying to cut the top from a full size piece rather than cutting 2" strips.
Like I said above, my plan is to take a 1/4" piece of glass 24" x 48" and cutting out the centers. I may break it but its the cheepest piece of glass in the project and if I break it Ill go another way. Or would you just go acrylic and cut out the centers. Maybe the acrylic is the way to go because of placing things in the tank and snaging the rim and breaking it if I make it out of glass.

Hope you can get a picture of what im doing and exacly what Im planning. I welcome any comments.

Thanks

[storrisch]

I think building a standard size it is hard to justify the cost and effort involved.

[RyanM]

<a href=showthread.php?s=&postid=10288539#post10288539 target=_blank>Originally posted</a> by storrisch
I think building a standard size it is hard to justify the cost and effort involved.

Is there a place that I can buy this tank? I was quoted $350 and that included the starfire front. Sounds really cheep to me but If I can buy this tank for cheeper than I would most definetly look into it.

[Keelay]

For glass tanks, its all in the black plastic trim pieces. The tank is really held together by the black ABS trim and sealed with the acrylic. You're right a bead of silcone won't keep the pieces together that well.

The bottom sits off the surface just like you said. This is why quite a few bottoms are tempered. This makes them quite a bit stronger. Both plate and tempered suffer from the point load issue. Maybe look into finding plastic trim. I think all-glass aquariums sell trim. You have a standard dimension tank in mind.

[hahnmeister]

For a starphire tank that size, you will want to go 1/2" thick. The bottom should be 1/2", and then tempered as well. 1/4" for the top is too thin to matter, and will be more of a liability from top impacts. I would just go 3/8" or 1/2" all around the top, or, skip the euro-bracing and just do a 1/2" thick, 4" wide center brace between the front and back panels.

Keelay, what are you smoking? The plastic doesnt do anything to hold the tank together unless it has a cross-brace(s) to prevent bowing on longer tanks. On tanks w/o cross bracing, the plastic trim is useless and can be removed 100% w/o a problem. You can easily build a tank, large or small, with just 100% silicone. Tanks in the US are made with plastic trim because its just easier for the MFG's to turn out huge amounts of tanks w/o attention to details like the bottom silicone bead, and w/o needing to flat polish all the edges. Tanks made overseas are 100% glass and silicone however.

Mine is...
http://www.wisconsinreefsociety.org/forum/viewtopic.php?t=91&start=0

That thread logs the building of my 120g XL, 48"x30"x21"h with 1/2" glass (starphire front and sides) and a tempered bottom. I built it with my side panels ON the bottom because I have some bottom holes drilled close to the back wall, and the extra glass came in handy for support. Otherwise, I would suggest that the side glass panels sit around the bottom panel, because it protects the bottom piece, which should be tempered, from getting chipped... because chipping a tempered bottom tank is not a good idea. In my case, Ill just be adding a parimeter piece to cover up the bottom glass, plywood, and foam anyways.

Otherwise, unless you want a custom size, I would also look into a standard, pre-made tank. If you want Starphire, Oceanic's Tech series would work well. My custom size was over $1200 for Miracles or Aq. Obsessed to make. I have made my fair share of tanks before, so I decided to do this one myself and got all the glass, tempered and drilled bottom, flat polished edges, etc... for about $600. In my case, it made sense. But for a stock size... not so much.

[woz9683]

because chipping a tempered bottom tank is not a good idea.
I'll second that :eek1: .

Just in case RyanM decides to use your tank as a guide Hahn, I thought I'd ask a couple questions/make a couple observations to clarify some things (of course I'm not at all curious myself :rolleye1: ).

I'm assuming that since the weight of your tank actually rests on the bottom, that's why you put the supporting plywood underneath it. Is this the reason? And since the plywood's there, does it really need to be a tempered bottom? Would it have been more or less expensive for you to go with a thicker bottom that was not tempered? And if the sides of the tank wrapped the bottom, would you still need a piece of supporting plywood on the bottom since there is no trim on the tank, or could you get away with just support on the edges?

And a note, Hahn your tank looks so different than mine. When I first started reading your thread I thought you'd changed your mind about the shape of the tank, and had gone with a standard 4' x 2' x 2' instead. It looks taller than mine, I think it must be the external overflow sticking out the back on my tank.

[hahnmeister]

Okay, tempering may make the corners more vulnerable if they chip, but it increases the strength of the bottom ALOT. I think if it wasnt tempered, I would have gone thicker... like 5/8" or 3/4". Tempered is just more impact resistant.

When I leak tested the tank, I had it supported by a parimeter of 2x4s and one along the center... much like the stand its on. I was able to remove the center support and stand in the tank... thats how strong it is.

If I wanted to, I could have suspended the bottom panel, no doubt. But then I would have to have a parimeter of glass added to the outer edge, and this would add more weight to an already heavy tank. And because of the holes in the bottom near the back, I would have had to had a whole plate made with holes drilled to match... or the bulkhead holes wouldnt be supported well. This would be very expensive, and then I would have to spend that much more time putting them on.

Tempering the bottom was dirt cheap... like $20. So yeah.... it was just easier and cheaper. FWIW, the tank is on styro to minimize impacts from inside the tank as well... so its pretty close to being suspended in that respect.

Yeah, the 8x8 overflow might make it look smaller than it really is. Ill admit, I havent gotten used to it yet. From the front, the refraction makes it look like its pretty shallow... but then I stick my hand in there and I realize its 30"!!

I wish I could have had a wider, narrower overflow, but this would have been its own complication since lets say the overflow was 12" long and 4" deep, rather than 8x8. But then the 3" thick euro-bracing would have made access very hard. I would have had to get the bracing contoured or something else custom (and expensive). I didnt see it as being worth it. The alternative was to have the overflow in the back left corner, as I would still have enough access. But eventually, this tank might not be in a corner, and so keeping the overflow from being visible on the ends was important.

If the sides were down around the bottom, I would still use plywood and foam on top of that. You could use say, a 3" parimeter and suspend it, but the hole placement gets complicated. Unless you really know what you are doing, I wouldnt bother. Just get the bottom tempered so it can handle the impacts of rock slides, and it wont matter. The $20 it will cost to temper it is nothing compared to the pieces you will need to have cut for a bottom parimeter and to possibly have holes drilled in that parimeter/ need to modify your holes. OTOH, lets say you plan on a cali/calfo style overflow and all your returns through the back wall rather than the bottom. Then it would be alot easier. Still... to get 3" wide strips of 1/2" glass to put all around the bottom will cost you a good $60-100... much more than the tempering. Tempering seems like the better way to me. Its how the custom mfg's like Miracles and OBsessed do it.

In my case, the only reason I put my top pieces ON the bottom was for extra support for the bottom holes. They were pretty close to the edge as is (two 1.75" holes and one 1.25" hole packed into this one overflow), so I wanted to be sure I had good support. If not for that, I would have put my sides around the bottom.

[RyanM]

Thanks for all the replys. I did do some checking and can get the same size tank prebuilt for the same money as the glass will cost me. Drilled with overflows for $330 localy. That is not starfire and its a solid black plastic trim and center brace. All things being equal the store bought is easier and faster however, the home built tank would be alot nicer I think. So Im still lost as what way I should go. And as far as how to best build it, There seems to be several different ways to do the same thing. What works best is a matter of some opinion. I am taking all this in tho so keep it coming and thanks.

[flyyyguy]

Ill just add that if you do end up building it make sure to make the back wall shorter and install either a full length or partial length external overflow box.

External boxes are the only way to fly if you have a choice. See if whoever making it can do that for you if you decide to buy it made. You wont regret the extra cost/effort I guarantee it.

Nothing to look at in the reef or to disturb your flow. Nothing but reef.

You can add that full length surface skimming is an added benefit, but is way down the list of benefits IMO.