Acrylic fabrication questions? I can help!

[jc03]

Big Bean fan...the glass tank I just got has that, haven't fired it up yet.

As far as acrylic goes, IMO, a hole will weaken a tank much less than a slot. A slot basically disconnects the panel from the top eurobrace, and thus must have additional (structural) bracing added to compensate.

Considering that you can put a few holes along the back and space them apart adequately without weakening the tank that much, I would go that route.

The reason I asked if the tank was new or used is that a used tank has material that has already been stressed during use. This means that you will have to make sure the back panel is nice and flat when joining the box, and this might be difficult. The other option is to just make boxes and hold them on with bulkheads through the holes. In that case, I would make both out of 3/8" General Purpose Plexiglas, should be nice and solid.

Floyd, I'm almost ready to drill the holes for my 2" bulkheads. Going with the Beananimal overfkow. What would you consider adequate spacing considering 3/4" acrylic thickness on the back panel. Thanks again for all your help. If be at a standstill without it.

 

[Floyd R Turbo]

Do you mean distance from the top/back joint, or spacing of the holes?

The distance from the top/back would likely be driven by the box dims, etc. You want to lay out the boxes so that the inner box determines the water level according to the height of the weir (notched or not) and then the exterior box just needs to have enough height to it so that the plumbing works as intended. Usually this means that as long as the top of the box extends an inch higher than where you are going to have your emergency standpipe open to at, you're good. It's definitely not going to need to be higher than the tank top.

Then, you want the bulkheads as low as you can place them. Ideally you want them fully submerged, all the time. So that usually means you will have them at least one hole diameter from the top/back joint.

Glass manufacturers usually recommend 2.5x the hole diameter between the holes. But if you look at any RR tank they don't exactly follow that rule. I would put at least one hole diameter between each pass-thru hole, the more distance the better, esp with large holes. Remember that if you are using 2" bulkheads, that's a heck of a lot of water that can pass through those.

What flow rate are you shooting for? overflow dims? # of bulkheads?

 

[jc03]

Do you mean distance from the top/back joint, or spacing of the holes?

The distance from the top/back would likely be driven by the box dims, etc. You want to lay out the boxes so that the inner box determines the water level according to the height of the weir (notched or not) and then the exterior box just needs to have enough height to it so that the plumbing works as intended. Usually this means that as long as the top of the box extends an inch higher than where you are going to have your emergency standpipe open to at, you're good. It's definitely not going to need to be higher than the tank top.

Then, you want the bulkheads as low as you can place them. Ideally you want them fully submerged, all the time. So that usually means you will have them at least one hole diameter from the top/back joint.

Glass manufacturers usually recommend 2.5x the hole diameter between the holes. But if you look at any RR tank they don't exactly follow that rule. I would put at least one hole diameter between each pass-thru hole, the more distance the better, esp with large holes. Remember that if you are using 2" bulkheads, that's a heck of a lot of water that can pass through those.

What flow rate are you shooting for? overflow dims? # of bulkheads?

Thanks Floyd. Yep, I meant distance between holes. I'm using (3) 2" bulkheads and going with the Beananimal overflow setup. I haven't built the box yet, wanted to make sure it's big enough to fit all the plumbing in it first. I'm shooting for 48"x10" without teeth. I've overextended my budget on the tank and everything so I'm stuck with the Dolphin Ampmaster I currently have which I think will do somewhere around 2500-3000 gph. I want to make it so I can upgrade the pump in time and not be restricted by the plumbing in the future.

 

[Floyd R Turbo]

What I do when I build the external box is start by placing the 3 drain bulkheads such that the flanges are about 1/2" apart, centered in the bottom panel. For 3000GPH you will want to use 1.5" bulkheads for these. Place the emergency in the middle, and the siphon and open channel on either side, with the 180s pointing to each side.

Then for the pass-throughs, place one dead center (lined up with the emergency) and the other two such that they are clear of the 180s by an inch or two. Then make sure they are low enough so that they are submerged both in the inner and outer box. Your 10" deep box should take care of this. The turbulence from the water passing through should not suck air in from the inner box this way, this will keep bubbles down. So by that design, there's no way you could have the holes for the pass-through bulkheads too close - they will be at least 5 or 6 inches apart.

I'll have to dig up a few pics of one I built and post them. Basically very similar to Reef Savvy's layout but not quite as wide. And not infringing on anything from them either, because you can't patent a drain system apparently - theirs just is related to the magnetic weir part I guess.

 

[jc03]

What I do when I build the external box is start by placing the 3 drain bulkheads such that the flanges are about 1/2" apart, centered in the bottom panel. For 3000GPH you will want to use 1.5" bulkheads for these. Place the emergency in the middle, and the siphon and open channel on either side, with the 180s pointing to each side.

Then for the pass-throughs, place one dead center (lined up with the emergency) and the other two such that they are clear of the 180s by an inch or two. Then make sure they are low enough so that they are submerged both in the inner and outer box. Your 10" deep box should take care of this. The turbulence from the water passing through should not suck air in from the inner box this way, this will keep bubbles down. So by that design, there's no way you could have the holes for the pass-through bulkheads too close - they will be at least 5 or 6 inches apart.

I'll have to dig up a few pics of one I built and post them. Basically very similar to Reef Savvy's layout but not quite as wide. And not infringing on anything from them either, because you can't patent a drain system apparently - theirs just is related to the magnetic weir part I guess.

Thanks Floyd. I look forward to seeing the pics. I may be a bit off but I planned on building the box in the tank and attaching it with the bulkheads. I see you mentioned external above. Are we thinking the same thing?

 

[Floyd R Turbo]

Sounds like you're talking about an internal box with the standpipes on the outside, the original BA.

Doing a internal & external box with pass-through bulkheads is a lot more flexible and forgiving. You can raise and lower the 180s in the external box, change the parts easily, no need for the screw-on caps, sweep 90 T's, etc.

Plus the inside box can be only 2" front to back, basically just enough room to get the nut on the bulkhead (flange in the external box) it's pretty slick.

 

[silentscream]

I'm going to be building a separate refugium for my system and want to have 3 sides black acrylic and only the front panel clear. I read that because it is difficult to determine how successful a black-to-black bond is, Floyd R Turbo mentioned using Weldon 40/42 as insurance. For a beginner such as myself, is this a reasonable task? Or am I better off building out of clear acrylic, then paint or use some type of vinyl to black out the panels I need?

 

[Floyd R Turbo]

It's less of a concern with a small system. If you are confident in your technique, and have been able to produce clear joints on a consistent basis, then you have less to worry about. The fear is that you end up with a bubble that you cannot see and that one time that a joint turns out bad happens and you can't tell.

If you are concerned, then set the joint normally and then apply a bead of 40 to the inside of the joint afterwards. Don't mess with making a 40 joint as those take a higher level of skill - beveling one bonding edge, making sure the pieces don't actually touch (results in a dry joint), etc. Just shore it up afterwards.

 

[jc03]

Sounds like you're talking about an internal box with the standpipes on the outside, the original BA.

Doing a internal & external box with pass-through bulkheads is a lot more flexible and forgiving. You can raise and lower the 180s in the external box, change the parts easily, no need for the screw-on caps, sweep 90 T's, etc.

Plus the inside box can be only 2" front to back, basically just enough room to get the nut on the bulkhead (flange in the external box) it's pretty slick.

I like the idea Floyd, just not sure if I trust my fabrication skills for the external box. At 48" I figure that would be holding quite a bit of weight.

 

[Floyd R Turbo]

You don't need the external box to match the internal box.

 

[silentscream]

It's less of a concern with a small system. If you are confident in your technique, and have been able to produce clear joints on a consistent basis, then you have less to worry about. The fear is that you end up with a bubble that you cannot see and that one time that a joint turns out bad happens and you can't tell.

If you are concerned, then set the joint normally and then apply a bead of 40 to the inside of the joint afterwards. Don't mess with making a 40 joint as those take a higher level of skill - beveling one bonding edge, making sure the pieces don't actually touch (results in a dry joint), etc. Just shore it up afterwards.

Thank you sir. I've built a few smaller items without bubbles, but this would be the first time I'm bonding something 16-18" long. I think I'll practice longer joints on a few scraps of clear before I work on the main piece. Worst case scenario, a 20 gallon flood on my wife's wood floor. :crazy1:

 

[Floyd R Turbo]

48" notched internal box

Both boxes

Close-up of external box (3/8" cast acrylic)

Here's how they line up (2" slip x slip pass-through bulkheads)

As you can tell I put the holes for the pass-through such that the bulkhead flanges are very close to the side/bottom panel. Maybe 1/2 or less of space. This works just fine, it's a small box, probably weighs more than the water that fills it, so making it 3/8" means it's really overbuilt. But I don't like making anything without a euro that is less than 3/8" (even an overflow box).

 

[Floyd R Turbo]

What I do when I build the external box is start by placing the 3 drain bulkheads such that the flanges are about 1/2" apart, centered in the bottom panel. For 3000GPH you will want to use 1.5" bulkheads for these. Place the emergency in the middle, and the siphon and open channel on either side, with the 180s pointing to each side.

Then for the pass-throughs, place one dead center (lined up with the emergency) and the other two such that they are clear of the 180s by an inch or two. Then make sure they are low enough so that they are submerged both in the inner and outer box. Your 10" deep box should take care of this. The turbulence from the water passing through should not suck air in from the inner box this way, this will keep bubbles down. So by that design, there's no way you could have the holes for the pass-through bulkheads too close - they will be at least 5 or 6 inches apart.

I'll have to dig up a few pics of one I built and post them. Basically very similar to Reef Savvy's layout but not quite as wide. And not infringing on anything from them either, because you can't patent a drain system apparently - theirs just is related to the magnetic weir part I guess.

I just realized that I had something backwards in my head - after posting the last pics I remembered that I put the bulkheads for the drains on the outside corners and one in the middle as shown in the last post.

This is done so that you can choose the order of your drains if you want. I use middle for emergency, then left/right for siphon & open channel, and place the 180s on those so that all 3 drains are in the middle. This way, the water flows through the pass-throughs but that flow path does not go directly to the drain points - the water must flow toward the center of the box and then goes down the drains. This decreases the chances of air getting sucked in either from pass-through turbulence or turbulence in the external box. Of course, if the external box has enough vertical depth to it, there will be zero issue with surface turbulence. This is the thing that I feel is missed the most. You have have your external box literally as deep as you want it because the level is controlled by the siphon valve settings and the position of the 180 on the open channel. Even if you had a 24" deep box, you could keep the level in the box at 1" below the tank water level if you tuned it right.

So the point is that you make the pass-through bulkheads as low as you feasibly can, as this minimizes turbulence hence bubbles. This is why the internal/external box works so much better also BTW, most especially at very high flow rates, because that water pouring over the weir inside the tank at 3000 GPH has a tendency to create a lot of turbulence, and ANY turbulence that creates any bubbles that get sucked into a 3000GPH drain pipe will get absolutely pulverized into microbubbles.

Also if you notice I found a great plumbing part to use for the 180s in the box. It's the lower part of a sink trap, it comes in 2 parts but I just throw away the other part of the trap, the 180 has a little drain cap that screws on (and has a rubber gasket) so you use that for the siphon line and leave the cap on, and for the open channel you just take it off and when the water rises above the top, it seals off and you have your secondary siphon. You could also leave the cap on but loosen it and remove the gasket, maybe just drill a few holes in it, as long as it doesn't get clogged up with tank gunk or salt creep it will let air into the open channel during normal operation. A lot easier than a John Guest fitting and airline tubing IMO.

 

[skeeter_ca]

On my Mini-Bean in a nano tank i'm building should I drill the holes on the tank and overflow pieces before I weld the tank together or after?

skeeter

 

[Floyd R Turbo]

I would most definitely drill all holes first. You can use a router & template and the sheet flat on the table to cut your holes first. If you mess up, you are still on the first step instead of the last (requiring a total rebuild).

If you're doing a bonded in place overflow (internal, external, or both) then build the tank first, do all your trimming and corner rounding, polishing, etc to the main tank, then install the internal overflow box, then the external. That advice may seem obvious but you never know when you might wish Captain Obvious showed up and pointed that out to you ahead of time.

 

[adova]

I have searched, but the results for the term "Crossbrace" in this thread are overwhelming, so i will just ask outright:

I have a tank build with 3/4" acrylic measuring 75 x 20 x 24(h). What is the minimum I can get away with and the recommended for eurobrace / crossbrace for 1/2" top?

Gluing up this weekend...

Thx!

Shawn

 

[Floyd R Turbo]

3" wide perimeter brace
6" wide crossbraces every 24"
1.5" radius on all cutouts
Round off all edges after routing (even with just a razor blade at a 45 degree angle to the edge)

If you want to use a thinner material for the euro instead of 3/4", you might consider widening the perimeter to about 4 or 4.5" instead of 3.

 

[adova]

wow - that is a lot more than expected. Is that for a low bow affect or for structural?

 

[Floyd R Turbo]

Yes, both. The euro is a critical structural component. Those dims came from recommendations of one of the best tank builders you could find (Acrylics / James Steele)

 

[adova]

Thanks again - I sketched up the eurobrace template and will go for broke soon.

Question about the assembly order - why is the top done before bottom? Or does it really matter?

And I would assume that it is important to glue up all 4 seams in the same run, correct?