Should I rip out my full-size overflow...?

[doughpat]

Hi everyone--

I just finished reading over a lot of previous posts on built-in overflow boxes, and I'm feeling a bit ill. I spent a lot of time building my island-style overflow, and now I think i've under-built it. It stands 22.5" tall in a 24" tank, and I built it using 1/4" acrylic. Now that I consider that the rest of the tank is made of 1/2" acrylic, I feel very foolish. Also, its shorter than I would like, losing some valuable height.

But here's the really wonderful part--its already welded in. I got a very good bond using Weldon 4, and gave a thick bead of 16 around the seams.

So I'm really considering ripping the #*!$ thing out and making a standpipe/overflow box combination. It wouldn't be THAT bad, just cutting the box off as low as possible, then re-sizing the box to fit the Durso standpipes (two 1.5"), welding on a bottom for the box, marking the appropriate locations for the new bulkhead holes, cutting the appropriate (and adjustable!) size standpipes, and whamo--new box. Not impossible, but what a PITA.

I'd really prefer not to do it (obviously), but if its a matter of potential flooding, then I have no choice. 1/4" acrylic bows pretty seriously under much pressure. I figured I could reduce the pressure by filling the overflow up first, giving it some outward pressure before the tank starts pushing in. Of course in that case, I should fill them both up simultaneously--every time. Sounds tricky.

Ideas? Possible medications to soothe my overworked soul? Jokes about not thinking things all the way through?

 

[bleedingthought]

Dude, you didn't think things all the way through!?!! :lol:

But seriously, have you tried out what you came up with? Fill it with water and see how it works out. If it's just the 1.5" that is the problem you could fix that easier than ripping everything out and put it up again.

 

[doughpat]

I know, I know, this is the first time I've ever made a mistake. Always wondered how it feels...

So how would you raise the water level in an aesthetically pleasing way? I figured I could just glue in another strip of overflow teeth (what PITA to router, by the way...30" of 1/4" slots...yech...), but that is probably about as much work as just reinstalling the box. I'd prefer not to use eggcrate of gutter guard.

Thanks for the advice. I think I'll fill it up first and measure the amount it bows. Any ideas on how much bowing is acceptable on 1/4" acrylic? The box is 19.5" long and 5" wide (and 22.5" tall).

 

[doughpat]

The more I think about this the clearer it becomes--I really should just reinstall this box. The hard part of this project was cutting the overflow teeth, which, if I decide to raise the water level by adding a higher strip or by adding eggcrate/gutter guard, was all wasted time. Gluing the actual box in only took 5 minutes, and so will cutting it out. The harder part will be getting the bulkhead locations exactly correct on the new bottom of the overflow box, especially because they are not in a straight line. There are three 1.5" holes (one for return--yes its oversized--and two for drain). I figure I will just place the bottom piece overtop of the holes on the tank, and trace the new holes. Then i'll just router out the new holes.

Ahhh yes, what project is complete without ripping out previously done work....

 

[bleedingthought]

Isn't the overflow internal? I don't think you should have problems with it bowing if it is internal and both the overflow and tank are filled. If you use a standpipe, the overflow will be filled all the time. Again, AFAIK this should be fine. But others who are more familiar with acrylic building will probably chime in a little later.

If you were to rip out the overflow, would you just add a new piece of acrylic at the bottom? If you think it's that easy then go for it. I have no experience with acrylic tanks so I can't help you there.

 

[doughpat]

Thiago--

Correct, both the overflow and tank will be pushing in on eachother, so the force should be minimal, other than the slightly lower water level in the overflow. I'm more concerned about the strange instances where the tank is empty and the overflow is full or vice versa (these are probably never true except when emptying and filling the tank).

One clarification--I plan to make an "overflow box on stilts". This is the 5-sided overflow box that is held off the bottom of the tank by standpipes. There are matching bulkheads both in the bottom of the tank and the bottom of the overflow box. Austin oceans makes these boxes commercially: http://austinoceans.com/products-overfl ... #overflows

Now I'm thinking about just ordering one from them. Man..the time I spend DIY'ing...just to slash the idea and buy the dang thing. Arrrghh...

 

[bleedingthought]

I didn't have time to look through it all (gotta run to work now and I'll look through it later ) and find out how it works but at least it's not that expensive.

 

[Hal1]

If you want to make the overflow walls thicker without ripping it out, why don't you just laminate anothe layer of acrylic on the inside or outside? You could even stop it short of the teeth so you don't have to cut matching teeth.