Help with C2C Weir Hole Placement

[adova]

I am planning a toothless coast to coast weir on the short side of a peninsula tank that has yet to be assembled / built. I am wondering the best way to cut the weir out:

1. Just cut off the top of the side by the amount of the height of the weir

or

2. Cut a rectangle out of the side piece leaving .5" on the top and sides of the weir.

Thanks...

Shawn

 

[adova]

A couple of images to illustrate the options. There will be Eurobracing which is not pictured.

 

[Gorgok]

With no tie-ins to the top bracing in the middleish of those panels in either of those examples i would say you have to treat that panel as a rimless build. As such it doesn't really matter which style, though i think the first is more practical and less likely to cause a mess. But you might want to step the slot off the sides more like the second one (but still open to the top), so the external box can be attached to a flat spot, instead of an edge seam. I don't know if there is any reason to do that really, but losing the 1" or so in the slot length wouldn't be a big deal.

 

[adova]

Not quite sure by what you mean by no tie ins to the top bracing. Perhaps I used the wrong terminology when i described it, but the top will have a 3" rim around the whole tank. The second option would tie into that whereas the first option could not.

I just was not sure if that was a big deal or not...

The box is being cut up tomorrow and is designed to be placed on the edge seam. But, everything is being cut with the CNC, so the edges should be spot on. Do you think this is still a problem - going edge to edge?

 

[woodnaquanut]

Not quite sure by what you mean by no tie ins to the top bracing. Perhaps I used the wrong terminology when i described it, but the top will have a 3" rim around the whole tank. The second option would tie into that whereas the first option could not.

Because there is a slot only the top of the slot will get tied in to the rim (euro brace). The rest of the side would be just like your other example since it's not really connected to the euro.

I'd do a notch and forget the euro on that end. Notch lets the OF box attach to the side not the front more like your second example.

What's the dimensions of this beast?

 

[adova]

ok - so i guess the root of the question is: Does the extra top of the slot add any value? Or better yet, is either option going to pose a problem with structural integrity? Tank size is 75 x 20 x 24(h).

 

[woodnaquanut]

ok - so i guess the root of the question is: Does the extra top of the slot add any value? Or better yet, is either option going to pose a problem with structural integrity? Tank size is 75 x 20 x 24(h).

If you put a screen on top, the slot might be useful to seal up that end of the tank. I have a slot OF and there is gutter guard behind it. Other than that I'm not seeing an advantage.

 

[adova]

Yea - Gutter Guard was already in the plan Thanks for the info and if anyone else would like to add, the more the merrier...

 

[uncleof6]

ok - so i guess the root of the question is: Does the extra top of the slot add any value? Or better yet, is either option going to pose a problem with structural integrity? Tank size is 75 x 20 x 24(h).

If it is a glass tank:

It depends on the glass thickness; which for a rimless tank needs to be: 19mm (3/4" nominal.) With full euro-bracing, it should be 15mm. That includes the panel you wish to slot or notch, either way. If you notch it, it should be 19mm glass. (rimless spec)

If acrylic, the panels will need to be thicker, and full euro-bracing will usually be mandatory.

I have done tanks both ways, and though I doubt you will take my word for it, I should have tried harder to talk the customers out of it. It really was not worth it in the end.

 

[adova]

If it is a glass tank:

If acrylic, the panels will need to be thicker, and full euro-bracing will usually be mandatory.

So you are recommending 3/4" acrylic for all panels and not just the one side? I had been thinking of maybe needing 3/4" for the weir side but I had been comfortable with 1/2" for everything else. I know there might be some slight deflection, but I could live with it if it were "safe".

 

[uncleof6]

So you are recommending 3/4" acrylic for all panels and not just the one side? I had been thinking of maybe needing 3/4" for the weir side but I had been comfortable with 1/2" for everything else. I know there might be some slight deflection, but I could live with it if it were "safe".

I am not the acrylic expert really, which is why I did not say how thick for acrylic. I refuse to ever own or work on another acrylic display tank. That's my opinion, and I am sticking to it. James (Acrylics) is the resident acrylic expert, and I would seek out his advice. He is not given to telling people what they want to hear, for the sake of telling them what they want to hear. Safey and tolerance are not uniform between people.

Just an opinion, however if the glass needs to be 15mm if euro-braced (mathematically derived + experience,) and knowing that acrylic is not rigid rather flexible, it would seem to me that 12mm (1/2" nominal) is not even safe, let alone tolerable. But again, that is just me: I won't tolerate the bowing, or the resulting pot bellied tank.

 

[adova]

I hear ya. I sent over the cut list to the acrylic people today and it includes sump, water tanks and the display. I just re-spec'd the cut list for the tank and (if I can get it to them in time) I think I can re-do all sides with 3/4" and only have to pay more for one sheet in 3/4" and leave the rest alone. Unfortunately, this is all going to be done on a CNC so my new spec will probably mean someone on their side needs to re-do the cut plan.

I think it would be stupid of me not to do that for the extra $130 in materials...

 

[adova]

Looks like I was too late to catch them before they cut . How often do you actually hire a company who is early?! I went ahead and added on another 3/4" panel for the 4 sides anyways. Worth the extra $$ to have it done right. The plastic company said they will work out a deal with me to help with the unexpected cost. Great crew over there at Plasticareinc.com (Denver)!!

 

[blueramSeattle]

Yeah, if you have a tank builder they have to think "will this fail and cost me money" and have safety factors. DIY is cheaper because it does not come with a warrentee.

I bought a used acrylic tank with an external coast to coast on the back. You can either order a full size side piece and mount the short one with a 4" or so spacing for a conventionalish overflow box. You can order a new side with cnc routed slots vertical along the top edge and the rest of the parts to make an external overflow.

Make sure you have the parts you want before you get out the glue. Cheaper to fix now.

 

[uncleof6]

Yeah, if you have a tank builder they have to think "will this fail and cost me money" and have safety factors. DIY is cheaper because it does not come with a warrentee.

(You is collective)

Well that is true to a point. But is it not also true that if you build a tank, you have to think "will this fail and cost me money?" Do you think that the safety factors, and mathematical relationships by which they are derived do not apply if the tank is DIY?

I get what you are saying, and yes, you are going to pay "me" for my time, and at least the cost of the materials. (Which is far less than you can get them for yourself.) On top of that there is sales tax (not my choice.) Included in the time, you are paying for experience and skills, as well as sharing the burden of over head such as catastrophic liability insurance (required by law,) and the cost of equipment, etc etc etc. What is reflected in what you pay towards over head is less than a fraction of the cost you would have to pay for the same things.

With all of that comes a conditional limited warranty (usually at any rate.)

Building it yourself, what will the materials and services cost, what is your time worth, what experience do you really have, are you truly skilled or watching videos on YouTube, and who will bear the cost if/when the tank fails? Yes "we" are concerned about the tank failing, but you should be also, probably more so.

 

[blueramSeattle]

I like to diy myself for the challenge and learning.

Have you decided on an internal overflow box on this tank or external yet. If you go external you can router out teeth so maintain the structural stability of the acrylic. Be careful planning your euro bracing and I almost got myself I to a situation when the bracing covered part (or almost all!) of the overflow box making service impossible.

 

[adova]

I am going to go external. But I want a toothless weir (I want it all lol!). I feel super confident now that I am at 3/4". Going to glue up starting this week. Been working on sump and water tanks all weekend. Feel free to follow the thread over here:

http://www.reefcentral.com/forums/showthread.php?t=2469666

Pics of glue up are on Page 3...