Acrylic Overflow box

[pdiehm]

Has anyone attempted to make an internal and external overflow box, similar to the design of the ghost overflow?

was talking to my father-in-law, who said it's possible, but would need to make sure the acrylic bonding agent is water tight.

I do like the design of it, but have questions about how it's attached, and how water doesn't get behind the internal box. It's fascinating.

another question I have is whether those 2 bulkheads are strong enough to keep that box upright on the back without any bonding reinforcement.

fascinating design...more I think about it, the more I think the external box makes a lot of sense.

 

[Gorgok]

Acrylic 'bonding' is welding, and when done right its essentially one piece of acrylic, so definitely water tight.

Water probably does get behind the box. But if there is a gasket between the box and the tank wall, then the seal remains solid. Attaching an external box to the assembly as well would require yet another gasket, again between the tank and the box. Basically, what you end up with is a big sandwich:

Bulkhead flange | gasket | internal overflow wall | gasket | tank wall | gasket | external overflow wall | bulkhead nut

 

[pdiehm]

Acrylic 'bonding' is welding, and when done right its essentially one piece of acrylic, so definitely water tight.

Water probably does get behind the box. But if there is a gasket between the box and the tank wall, then the seal remains solid. Attaching an external box to the assembly as well would require yet another gasket, again between the tank and the box. Basically, what you end up with is a big sandwich:

Bulkhead flange | gasket | internal overflow wall | gasket | tank wall | gasket | external overflow wall | bulkhead nut

Do you think it's plausible to make something similar? Instead of having teeth though, have say a 3/8" gap between water and a lid to provide a flat skimming area?

The other question I have to ask is whether it would be cost effective to make it, or just wait and pay for it, though, I would change the hole design, from 2" to 1.5" bulkheads in the internal box, and 1" bulkheads in the external drain box.

It's fascinating that the only thing keeping that box attached are 2 bulkhead nuts.

 

[Gorgok]

Building a couple of 5 sided boxes like that is very easy i think, its just simple cuts with some holes. Especially without any teeth, which are bad anyway, nothing hard in the whole thing at all. The internal box doesn't even need to be all that strong, but the external one does have to carry the plumbing (at least partially, it should be supported with clamps) and not tear off the wall (its a lever attached on a flat face). Some internal bracing near the bulkheads would help, or having edges on the top side, or both. Thicker material than the internal wouldn't be bad either.

Most of the weight will not be on the nut, it will actually be on the bulkhead stem in shear. Some will be pulling the nut out (the lever aspect of the whole setup will pull on the top edge of the nut the most) but some will also be pushing into the tank wall (the bottom edge, which will most likely not go anywhere...). I don't know how strong bulkheads are, or which ones you plan to use, but unless the box is huge (and more specifically very wide making the lever bigger) it will probably be just fine.

 

[pdiehm]

Just laid it out on paper.

1/4" acrylic x 24" x 24" sheets (2) = US Plastics $83.80

Internal Box dimensions: 24"L x 5.75"H x 1.5"W, with 2 1.5" bulkheads
External Box dimensions: 24"L x 6.5"H x 4.5"W with 3 1" bulkheads on the bottom. I did add 2 cross braces at the middle top section.

I would think the box would easily be held by the bulkhead nut...maybe I'd be better off going with the 2" bulkheads draining into the external box, for the added strength of the nut.

As for bulkheads, probably the schedule 40s.

And that's if I went with the 24" overflow. I could go with the 16, but on a 60" tank, the 24" overflow would give me better surface skimming IMO.

 

[Gorgok]

Internally i think 1/4" is fine, but i'd probably want at least 3/8" on the outside. Its not for the weight or anything, but if it gets bumped into, being a thing that sticks out of the tank, i'd rather it not break...

Also, all your water has to pass through the 2 1.5" bulkheads, ideally without noise (around 1/2 full of water). Having more than 2 would probably be smart. Don't know any calculators for this. Fitting a 3rd or even 4th hole wont make the box any bigger even with safe drilling spacing.

 

[supra400hptt]

I just built mine out of 6mm acrylic. I used 1 1/2" bulkheads between the two and 1" in the external. The key is in the cuts. Cuts have to be smooth, straight and to the millimeter. I get the acrylic shop to cut my pieces to size then it's just a matter of gluing together. I use weld-on 4. I didn't do teeth, instead I have a piece of gutter guard in the internal box. This let me make the internal box a little smaller and maintain the same amount of flow as if it had teeth. I'll probably do a brace or two inside the outer box. Still waiting on tank to be built. It's set up with emergency drain, return back up through the box which with go to a sea sweep, siphon drain, and trickle. I've haven't put the piping and elbows in yet. The hardest part is planning out the size. I think the acrylic only cost me around $40 cut.

 

[pdiehm]

I just built mine out of 6mm acrylic. I used 1 1/2" bulkheads between the two and 1" in the external. The key is in the cuts. Cuts have to be smooth, straight and to the millimeter. I get the acrylic shop to cut my pieces to size then it's just a matter of gluing together. I use weld-on 4. I didn't do teeth, instead I have a piece of gutter guard in the internal box. This let me make the internal box a little smaller and maintain the same amount of flow as if it had teeth. I'll probably do a brace or two inside the outer box. Still waiting on tank to be built. It's set up with emergency drain, return back up through the box which with go to a sea sweep, siphon drain, and trickle. I've haven't put the piping and elbows in yet. The hardest part is planning out the size. I think the acrylic only cost me around $40 cut.

That looks sweet. What size is it and for what size tank? Basically you used 1/4" acrylic. Not sure if there's any acrylic shop near here. will have to look.

 

[mcgyvr]

cough.. cough.. estreetplastics.com for your materials.. (easily half the price of usplastics,etc... (1/4" x 24" x 24" is $19.99)
just need a table saw to cut it. and some weld-on #4 (or 3) to weld it all together.

IMO though if you have to ask if its even plausible you should just buy something pre-built.

 

[pdiehm]

cough.. cough.. estreetplastics.com for your materials.. (easily half the price of usplastics,etc... (1/4" x 24" x 24" is $19.99)
just need a table saw to cut it. and some weld-on #4 (or 3) to weld it all together.

IMO though if you have to ask if its even plausible you should just buy something pre-built.

Hah, thanks.

Never done a build like this, so I'm in murky waters. I feel like I ask 500 questions a day.

Originally was going to do a quasi-coast to coast overflow, drill 3 holes, plumb it and go from there. Saw someone's external box, made out of glass, attached by silicone, and got me googling boxes, and saw the reef savvy ghost overflow, and got to thinking...its 12 pieces of plastic, with 2 holes in 2 of the pieces, and 3 in another piece. Even better is, it's apparently held up (and rather strongly) by 2 bulkhead nuts, which means no siliconing fo a nice cleaner look.

To say that I'm looking forward to this is an understatement...right now it seems like it's all in the planning phase.

 

[pdiehm]

In looking at estreetplastics.com, it appears they manufacture plexiglass. I was under the impression you don't want plexiglass but rather true acrylic.

 

[supra400hptt]

That looks sweet. What size is it and for what size tank? Basically you used 1/4" acrylic. Not sure if there's any acrylic shop near here. will have to look.

1/4". Inside box 12"W x 6"H x 1.5"W. Exterior 16"L 6.75"H x 3.5"W. Plexiglass is a brand name of acrylic. You generally want cast vs. extruded acrylic. There is a huge thread on here about acrylic where I learned everything. You can find premade boxes on bulk reef and ebay if you don't want to build or can't get the acrylic.

Oh, tank will be 48W x 24H x 29 deep.

 

[pdiehm]

1/4". Inside box 12"W x 6"H x 1.5"W. Exterior 16"L 6.75"H x 3.5"W. Plexiglass is a brand name of acrylic. You generally want cast vs. extruded acrylic. There is a huge thread on here about acrylic where I learned everything. You can find premade boxes on bulk reef and ebay if you don't want to build or can't get the acrylic.

Oh, tank will be 48W x 24H x 29 deep.

I saw the thread, however I'm not allowed to view the images on it for some reason.

 

[mcgyvr]

In looking at estreetplastics.com, it appears they manufacture plexiglass. I was under the impression you don't want plexiglass but rather true acrylic.

Plexiglass is simply a trade/brand name for Acrylic..
Its cast acrylic.. what you don't want is extruded acrylic for any structural pieces.

My overflow is actually polycarbonate because I had tons lying around.
Very similar to acrylic but more impact resistance basically.

estreet stuff is totally fine.. (as long as its cast)..
I used their tubing which is extruded for my skimmer.

 

[pdiehm]

Plexiglass is simply a trade/brand name for Acrylic..
Its cast acrylic.. what you don't want is extruded acrylic for any structural pieces.

My overflow is actually polycarbonate because I had tons lying around.
Very similar to acrylic but more impact resistance basically.

estreet stuff is totally fine.. (as long as its cast)..
I used their tubing which is extruded for my skimmer.

sent them an email.

Doing more reading , I wonder if an overflow like this would be too much. But I can dial it down right to match A) the skimmer and B) the return pump?

 

[IPT]

FWIW I was thinking to do acrylic too. I then found out my glass shop could cut me the 3 pieces (you would just need two for coast to coast) for like $30. I know it will last forever, no adhesion issues with acrylic/silicone. You may be set on this other method but too me all those bulkheads and numerous sandwiched gaskets were just all potential leak points.

Good luck with whatever route you choose I'm sure it'll turn out well.

 

[pdiehm]

I thought about glass but there isnt anywhere near here that cuts glass, and the glass at HD/Lowes is 3/16".

I havent decided yet, and may just buy the premade one. I really dont want teeth on it but thats all i am seeing.