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Unread 02/12/2011, 10:39 AM   #1
smithj108
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Join Date: Dec 2005
Location: Tampa, FL
Posts: 98
DIY Triangle Tank

For many reasons I've decided to set upon building a triangle-shaped glass/plywood hybrid-like tank. Sure, it's easy to find pre-fab 100% acrylics, but I'm old-school and for various additional reasons, I want glass, and aside from bow front or round corner tanks, I don't see anything I like. The tank shall support various installation options such as; corner of a room (the obvious one), against a open flat wall (would offer two viewing profiles), and finally as a center display (full 360° walk-around).

That said, I'm in the initial engineering stages of tank design and I wanted hear some validation or alternative ideas.

Tank size is not too big: 3' x 3' x 4' --> 21" tall
Est 45-50 gal

1] Bracing
First is on tank bracing. I don't have a problem with bracing being a part of the design, I'm just not 100% on how to best implement it on this shape of tank. Even more specifically I'm concerned with the glass joints on the two 45° corners. I've attached a pic to help visualise this.

As you can see, it will be a typical right-angle triangle shape - meaning we have one 90° joint (BA) and two 45° joints (BB & BC). Obviously the 90 is pretty standard and doesn't really require bracing. However, on the 45's the glass edges don't fit flush and I doubt I can get them bevelled nor would really I trust the integrity of bevelled edges here. Instead, my current thought is to ironically use a formed strip of acrylic on the outside of the tank and silicon fill (illustrated in red) the entire thing in-place. Other materials might include painted aluminium (uh, not), and wood (bulky). Questions swirling in my head are: thickness of acrylic, how/who can form it, how well silicon bonds to glass and acrylic material?

I'm thinking the acrylic brace wouldn't really need to be all that thick, and if fit tightly would off sound distributed support. Any thoughts?

Oh, and although a brace on the (BA) corner wouldn't be required, I'd opt to have it just to keep the tank aesthetics uniform - I plan to make this an omni-direction tank for viewing from all sides.

Top tank or rim bracing can be either more acrylic, or water-proofing a wood upper frame which could tie into the hood design.

2) Bottom construction
Second, I am considering framing-in the base of the tank. This is where things get very unconventional. Instead of the typical tempered glass bottom panel, I am considering a fully plywood bottom, framed-in, re-enforced with concrete backer board (optional), and typical 2x4 supports, water-sealed with two-part epoxy. Then, for the final inner-layer, I was thinking thin acrylic to protect the water proofing paint/epoxy from being possibly scratched/punctured by live rock and cleaning. Think of the acrylic sheet as a liner for the bottom. It doesn't have to be thick, nor waterproof as the epoxy treatment on the plywood take care of that. Sure, I'd do a good job at sealing the acrylic layer to prevent water getting behind, but I just want to emphasize the acrylic is simply for tank bottom durrability.

See attached pic - not in scale but shows a cross-section of the layers for the tank bottom. Building a custom bottom allows me to construct the bottom and frame as one solid piece and provide the side glass panels rigid support. True, it will be heavy - but strong. The bottom will then interface on top a custom-build stand.

I'd love to hear any thoughts, past experience, or any potential pit-falls in these design - thanks!


Attached Images
File Type: png Tri-tank_pic01.png (17.3 KB, 82 views)
File Type: png Tri-tank_pic02.png (21.9 KB, 80 views)
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