questions about Bean's overflow

[jacksonpt]

I know a couple of you are running Bean inspired setups... I've got a couple of strength/support questions...

If I had an inner box and an outer box made up, both out of acrylic, could I use 2 bulkheads to "connect" them to the tank? i.e. could I drill both boxes and the tank for dual 1.5" bulkheads, then use the bulkheads to hold the boxes in place? Would that be strong enough?

I'm not sure if I would run 3 drains in classic bean style or go with just 2 (i.e. herbie)... but either way, does the outter box need to be reinforced or supported at all to hold the plumbing?

I'm thinking about something along these lines:

• a long and narrow inner box (something like 24"L x 1"D x 4"H)
• a larger outter box (something like 12"L x 3"D x 6"H)
• two 1.5" bulkheads connecting the two boxes
• a .5" full siphon drain and one or two 1" traditional drains

 

[Capt_Cully]

I see where you're going. I'm not sure I'd trust the bulkhead to support that weight. Especially over time. Now, if you were able to use an internal box that was acrylic and a glass external box, that'd be different. You could attach the glass box with silicone in a traditional fashion. It will be supporting its weight as well as the volume of water within, it. I would say you could then support the internal box with the bulkheads, but I'd reinforce that with silicone too. I'm an overkill kind of guy.

If the internal box is only 1" deep, and accounting for factory trim (unless you're Rimless) you will have trouble getting a bulkhead's profile to line up where you want it. You'll need more than one inch even if its a small bulkhead. Even, for arguments sake, if the bulkhead did fit in the one inch depth, the internal box would end up being lower than you wanted if you account for the tanks trim AND to get the bulkhead where you wanted it for the water level in the EXTERNAL box.

Does this help? Am I reading your proposed schematic correctly?

 

[Capt_Cully]

Ah, 1" front to back. 4" tall. Got it. Disregard second paragraph.

 

[jacksonpt]

is weight the big issue... putting the weight if the exterior box, when full of water, on a smaller area where the bulkheads are placed? Could I build a shelf to support the weight?

Just weighing the pros and cons along with costs of glass vs acrylic...

 

[Capt_Cully]

I'd say weight and trusting the bond between acrylic and glass with silicone. I mean, I'm no materials expert, or engineer, that's just what the consensus is here on RC.

 

[jacksonpt]

Weight I get... but there shouldn't be any bonding to have issues with, should there? Assuming both boxes are well built and leak free, then the bulkhead seals would make everything water tight, right? I wouldn't be bonding the acrylic to the glass at all.

 

[Willistein]

I think this would work. I would put a bead of silicone around each bulkhead between the inside of the tank and the back of the inner box. Not even on the bulkhead itself, jut between the glass and the acrylic. I don't think weight will be an issue, bulkheads are pretty strong.

 

[Capt_Cully]

Yeah, ok, I see, I was thinking you'd attach the boxes. I derailed myself suggesting a permanent attachment. I suppose a shelf would suffice in that stead.

I guess the only thing left to question, then, is the integrity of the threads and nut of the bulkhead. Anyone who's ever over tightened one knows their tolerances fail quite abruptly, although they do withstand good pressures up to that breaking point. What I mean is they aren't very plastic. Finger tight good good good, too far with the wrench and pop!

So what's my point? Will the tightness required to hold a fluid filled box onto the outside of an aquarium withstand the test of time? Will it require tightening to a point that you are close to it's theads maximum tolerance? Like I said, I'm an overkill guy. Primarily because a leak is just not an option for my wife and therefore myself

 

[Willistein]

Here a diagram. The red seal is the rubber ring supplied with the bulkhead. The green ring is another rubber ring that you will have to supply. The blue ring is the silicone seal that I mentioned. It will prevent water from going down between the inner box and the glass and escaping. post pics when you make it - sounds like a good idea.

 

[jacksonpt]

So what's my point? Will the tightness required to hold a fluid filled box onto the outside of an aquarium withstand the test of time? Will it require tightening to a point that you are close to it's theads maximum tolerance? Like I said, I'm an overkill guy. Primarily because a leak is just not an option for my wife and therefore myself

But again... if the shelf was holding the weight, all the bulkheads would have to do is hold the box against the tank... essentially just seal everything together, not actually support anything, right?

 

[jacksonpt]

Here a diagram. The red seal is the rubber ring supplied with the bulkhead. The green ring is another rubber ring that you will have to supply. The blue ring is the silicone seal that I mentioned. It will prevent water from going down between the inner box and the glass and escaping. post pics when you make it - sounds like a good idea.

Any reason I couldn't use another seal, rather than the silicon, just for the sake of simplicity?

 

[Willistein]

Any reason I couldn't use another seal, rather than the silicon, just for the sake of simplicity?

Nope, should work fine.

 

[Capt_Cully]

But again... if the shelf was holding the weight, all the bulkheads would have to do is hold the box against the tank... essentially just seal everything together, not actually support anything, right?

Yeah, that's what I was thinking. I personally would want something besides the bulkhead to support the weight of the box filled with water. Your proposed shelf should do it.

Over time stresses add up. I'd think that the seals on the box itself, or the threads on the bulkhead or it's nut, could fatigue. Maybe I'm belaboring the point, and being a worry-pants, just trying to help you safeguard against potential disaster.

 

[jacksonpt]

just trying to help you safeguard against potential disaster.

Definitely... that's why I ask these types of questions. I'm also trying to figure out what are probable short term problems vs possible long term circumstances... so I definitely appreciate the thoughts.