Rimless low iron tank build

[travisurfer]

nice job

[edacsac]

Oh, and yes, nice job! especially for a first tank not having any leaks or problems!

[Ebn]

Damn dude, looks pretty good.

 

Interested in building a sump for me? Considering a sump tank to sit right next to my starfire.

[supernip]

i guess I should update. I'll do that later tonight

[jaidexl]

so, how large do you think that you could go with that type of construction before the water volume would blow the seems out? Just curious, because I can definitely see how that would work for you smaller nanos, but I would be nervous as hell going 24+ gallons with no reinforcement.

There are definitely large rimless tanks out there, but for DIY, there comes a point where you have to ask yourself "is it worth the hassle and risk?".

 

If you feel like reading 44 pages about scolley's "Big Clear Kahuna" on plantedtank, you'll see what a nightmare it was to build. It recently blew it's entire back off with no warning.

 

i guess I should update. I'll do that later tonight

The tank looks great, supernip. I have one question for you about measurements that will help me with my first build. When subtracting the 1/4" from the inside panes, do you also need to subtract room for the seam? In my plan I have some baffle panes that will slide inside the tank, I don't want it to be too tight of a squeeze. And I don't want the bottom pushing the sides out and messing up the corner seems.

[supernip]

There are definitely large rimless tanks out there, but for DIY, there comes a point where you have to ask yourself "is it worth the hassle and risk?".

 

If you feel like reading 44 pages about scolley's "Big Clear Kahuna" on plantedtank, you'll see what a nightmare it was to build. It recently blew it's entire back off with no warning.

The tank looks great, supernip. I have one question for you about measurements that will help me with my first build. When subtracting the 1/4" from the inside panes, do you also need to subtract room for the seam? In my plan I have some baffle panes that will slide inside the tank, I don't want it to be too tight of a squeeze. And I don't want the bottom pushing the sides out and messing up the corner seems.

 

 

the kahuna broke due to negligence on the owner's part.

 

I didn't subtract the extra space for the silicon, because I don't have the technical proficiency to to silicon between the seams. The more I think about it, the less necessary it becomes because of the way silicon bonds to glass. It might help, but I can do without it.

 

I don't have any baffles so I couldn't help you there. I would imagine you'd have to go smaller by a few mm. as for the corner seams, what I did with my acrylic "overflows" was round the bottom corners.

[tperkins]

The more I think about it, the less necessary it becomes because of the way silicon bonds to glass. It might help, but I can do without it.

 

 

I have never understood how the thin layer of silicone between the panes of glass gives it more strength than the large seam in the corner. I guess thats why I am not an engineer!

[supernip]

if the seam fails, the little layer gives a bit of relief by adhering the two panes together? helps to distribute the force in the event of.

 

Or that's my guess. I did a thick seam so I'm not too worried about that. My tank's small anyway, a leak is more likely than a catastrophic seam failure

[jaidexl]

I have never understood how the thin layer of silicone between the panes of glass gives it more strength than the large seam in the corner. I guess thats why I am not an engineer!

It's my understanding that this is how a silicone bond is meant to work, and is it's strongest, with force pulling away from it. This is why aquariums have the bottom pane meet the inside of the side panes rather than the sides sitting on top of the bottom, where the pressure on the sides will shear the side panes off of the bottom since silicone has poor strength in that scenario with "side to side" force, rather than the force pulling directly away from it.

[neanderthalman]

It's the difference between a tensile strength and a shear strength. Many adhesives (and fasteners) are extremely strong if you try to pull them directly away from the surfaces they are bonding. This is the tensile strength. If instead you try to slide the two surfaces against each other, may adhesives will fail. This is the shear strength, and for many adhesives like silicone, it is rather low. Typically, the shear strength for an adhesive is lower than the tensile strength. That's just from personal observation, at least.

 

I'm an engineer, but I never studied adhesives, so I have no idea why it's like that. There is someone on this board who makes polyurethane glues, but I don't remember who. I'll try to figure it out and ask them.

[jaidexl]

That's it, much better explaination.

[edacsac]

It's the difference between a tensile strength and a shear strength. Many adhesives (and fasteners) are extremely strong if you try to pull them directly away from the surfaces they are bonding. This is the tensile strength. If instead you try to slide the two surfaces against each other, may adhesives will fail. This is the shear strength, and for many adhesives like silicone, it is rather low. Typically, the shear strength for an adhesive is lower than the tensile strength. That's just from personal observation, at least.

 

I'm an engineer, but I never studied adhesives, so I have no idea why it's like that. There is someone on this board who makes polyurethane glues, but I don't remember who. I'll try to figure it out and ask them.

 

I'm confused... So from what your saying, applying a bead in between the glass panes is stronger than mating the panes and applying the silicon on the inside seem? The bead between the panes being tensile, and the bead in the seam being shear?

[jaidexl]

No, aside from corner beads, this is a comparison of resting the side panels on top of the bottom pane rather than the sides pushed against the bottom's edge, the latter is the strongest because the pressure is pushing the side away from the bottom pane and the seam would be tensile rather than shear.

[edacsac]

Gotchya!

[jaidexl]

edited it a bit to make more sense, I've never been good at explaining that one without a pic.

[neanderthalman]

Yes. Most of the strength will come from the thin thin layer of silicone between the two panes of glass, not from the concave bead. Very little actual adhesion strength is provided by that bead.

 

The bead might make the seam slightly stronger by reducing stress concentrations (from a sharp change) at the joint. It's geometry though, not adhesion. I'm pretty sure it'd be minimal, there are a lot of high-end tanks that do not have the large bead of silicone, like ADA tanks.

 

The reason it's there is probably because it's the cheapest/easiest way to make the tank.

[supernip]

i could only hope to make that layer and have my tank look clean. it's harder to execute than you might expect when all you have is a roll of duct tape, 2 chopsticks, a roll of raffia and a pair of latex gloves.

 

I felt like freaking mcguyver

[supernip]

painted back and bottom (krylon fusion is amazing!),made an overflow and will be siliconing it on tomorrow

 

[Sebea]

great build nips. You the man!

[rotarymagic]

Sorry to reanimate this thread, but what ever happened to this tank?