lookout: plans to build a tank.

[dansemacabre]

I'm insane. I really am. I've had my 125 for, oh, 6 months? I'm already wishing it was larger. So, I like GARF's little script that generates cut sizes. The instructions are a bit lacking, as is to be expected with such a generic program for giving tank building directions, as each size will definitely look/be different. I have a few questions, as the actual building will be many months to a year away. My questions are:

1. Does anyone know of a site with more detailed directions?
2. The brace sizes on the GARF page are a bit confusing...if it's how I have in the diagram below, the sizes are throwing me off.
3. Any other general tips or advice? I'll be making one that is 96x26x26 (LxWxH) out of glass.

I'm thinking 4 overflows, one per 2-feet of tank...probably with double standpipes in each overflow box. And 4 return holes...I'll probably put a T fitting in each and go a foot in both directions, spray-bar style. Or I might just go with strategically angled PVC.

Overflow boxes also probably made from glass? Or perhaps acrylic boxes are better? I know you can order acrylic overflow boxes.

Anywho, ANY and ALL thoughts/opinions/advice are greatly appreciated!!

 

[dansemacabre]

anyone?

 

[jsoong]

OK, here's my 2 cents' worth.

From an engineering standpoint, it is best to put your 2x4's on end. Therefore, in your pic, all the widths (rails, braces, etc) should be 2" (actually that is nominal dimension, actual size of a 2x4 is 1.5" x 3.5" - so the width is really 1.5").

Since the rails are supporting the weight of the tank - force is generated in the vertical plane. The force will tend to bend the rails, so best to have the 2x4's on ends so you have the 3.5" to resist the bending. BTW, if you want to overbuild, you might consider 2x6 rails for a really big tank. This, incidentally is stronger than having 2 2x4's ganged together, or even a 4x4.

The cross braces are there to keep the frame from bowing out ... There isn't much bowing out force in a fish tank, so you can do whatever is convienient.

One thing about the GARF stand I don't like is the way the rails are joint to the legs. They are glued/screwed to the sides of the legs. Since the tank weight is pushing the rails downwards, it is tending to shear the rails off the legs. Much better to join the rails so they sit ON TOP of the legs. That way, even if your joints fail, the tank won't come crashing down. Although the joining requires more work, I think it is worth it.

If you want to see how I join the basic frame together, you can see some pics on my thread here:
http://www.aquariumadvice.com/viewtopic.php?t=23675

There were also several stands built with similar joints in this forum.

 

[dansemacabre]

Thanks for the tips, I'll use them for the stand.
This thread is about the actual tank itself though. Got any advice/thoughts/links on that? Thanks for the tips!

 

[jsoong]

Oops, I thought you were talking about the tank stand when I saw the GARF reference!

I did quite a bit of research when I was thinking about building my own tank (in the end, got a used one instead). I have gotton rid of my tank building links, but there are better instructions than the GARF one out there.

As I recall, for the brace, you cut strips of glass & run it all the way around the tank. Plus, you add a center brace or 2. So your picture has the general idea right. The braces are important as that will prevent the bowing out of the tank - which can be considerable in a deep tank like yours. Since the force is horizontal in this case, you would orient the glass horizontally.

The bracing needed also depends on the thickness of glass used. The old tank I got (4' - 70 gal) has no center brace (while all the newer ones do). The glass is 1/2",however, at least 50% more than the standard, and I have less than 1/4" bow out.

For a long deep tank, I would research more before settling on the width of the glass. I was researching 80 gal designs & most places suggest a 4" rim brace and a 6" center brace. For your 8' tank, I would imagine needing either wider rim bracing or thicker glass. However, since I didn't build a tank myself, all I can offer is hearsay & not actual experience.

I was also a bit confused on how to join the long braces to the cross braces. I don't think you would edge join them. From my reading, I would think you join the long braces to the front & back panes. Then you run the side & center braces all the way joining the front & back panes together. That would mean the cross braces would be either above or below the long braces... make sense?

In the end I was looking more at DIY acrylic tank. Those designs have solid tops & smallish cut out - making for bracings that are 8" or 12" wide. If I can locate some of the old links, I'll post them.