New wood tank. Need help with front glass calculation.

dsandfort

Premium Member
I'm getting ready to build a plywood tank stealing various ideas from this and other forums. But, I have a question on glass. There seems to be a magic 30" height for large glass fronts based on my reading.

I want a tank 96" long and 42" front-to-back. I also want 28" viewable height. So, I figure that I want a 4" lip on the botton of the view side to seal the glass to and hide most of the sand cross section. I want 3" lip on top to seal the glass to. That means I need a piece of glass 35" x 96". But I also plan to cut the rear overflows so the water level does not exceed 32" (including the depth of sand). Roughly 3" of glass will be above water level.

Based on 1 glass thickness calculation I found, this means I need glass thicker than 3/4" but not as thick as 1". Since the only load that will be on the glass is compression, and it will have at least 3" of silicone support all the way around, I'm feeling OK with 3/4".

Comments/Suggestions/ideas?

Thanks in advance.

Del
 
Kent: When you siliconed the glass to the tank, how much glass to wood overlap did you have? I'm thinking 2" all around.



I'm planning to build a plywood tank too, 96x48x35(H) but water level will only be up to 30-32".

I've done alot of reading a few years ago and forgot all the specs. I've done hours of reading lately and so far, people building 96x30x30 or something of that size, 1/2" should be okay but don't quote me on this.

If anyone can give me a good link to a 96x48x30 plywood tank (search function always disabled), that would be great. The glass mounting part (or acrylic) is what I need to learn more about.

Here's one I found here that is essentially the same size I want to build. He used 1/2" glass. No long term test, he took it down after 2 weeks b/c parents didn't want it indoors but his project is well documented.

http://www.jonolavsakvarium.com/eng_diy/2200litre/2200litres.html

I'll go 1/2 to 5/8". But until I know 1/2" is okay for 600G (96x48x30h), I'll use 5/8" or 3/4" but I'm hesitant to use 3/4" or 5/3". It's going to be PITA to work with. I am still considering acrylic due to clarity but I haven't found any good links as to how well plywood tanks hold up with acrylic. Starphire is a possibiltiy, but how expensive for it nowadays? I can probably buy it from Miracle.
 
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I have about 1/2 to 3/4 overlap. That is plenty. Also, there is no deflection at all with 1/2 glass.

The glass itself is only is 25" deep. The plywood frame is another 4 inches but the glass doesn't take that pressure. Plus there is one inch at the top of the tank that doesn't have water. You have to have some room for wave action.

So, plywood tanks that are 30" deep can use half inch glass.
 
Kent: Thanks for the info. I'll keep that in mind.

I can't wait to start up my own thread for my project. I'll probably start buliding slowly early next year, beginning with the stand. I need to at least partially finish the basement first.
 
hello,
Heres the tank i built, its pretty much the exact dimensions as yours.

Overlap on the pane was 2" top and 1-1/4" bottom and 2" on the sides.
For both the end and face panels.

The reason for the bottom being a smaller overlap was to allow for the large bottom canstripping.

Glass was 3/4" laminated Starphire....when i built it, i remember coming up with half inch minimum, so i overkilled it.

http://www.reefcentral.com/forums/showthread.php?threadid=686757

Hope that helps a bit.

Marc.
 
If you think about the overlap on a just a plain glass tank it's very small. I'm sure 2" is very very safe, and is overkill.
 
Fudge,

You're definately right! That is exactly what I want to do! Your system looks amazing and with lots of toys and goodies!

I was planning, like other plywood tanks to add metal bar or more to prevent bowing. I read that you used 2x4's all around the top. It looks really beefy and I like it. I doesn't look like you used just 2x4s around the top. Unless you used 2x8 and then 2x4 on top (or something like that) because I see a stepped rim. Do you notice any bowing? By the looks of it, it doesn't look like it will and if it does, not noticeable.

Good to see another Canuck around here. Many years ago, when I researched the price of standard glass 3/4" 96ishx30ish I think it was around $300. I would love to go Starphire, but I hear it's 3x more. May I ask how much you paid for 3/4" laminated Starphire and why laminated over solid 3/4"?

TIA,

James
 
<a href=showthread.php?s=&postid=8440156#post8440156 target=_blank>Originally posted</a> by James Yeung
Fudge,

You're definately right! That is exactly what I want to do! Your system looks amazing and with lots of toys and goodies!

I was planning, like other plywood tanks to add metal bar or more to prevent bowing. I read that you used 2x4's all around the top. It looks really beefy and I like it. I doesn't look like you used just 2x4s around the top. Unless you used 2x8 and then 2x4 on top (or something like that) because I see a stepped rim. Do you notice any bowing? By the looks of it, it doesn't look like it will and if it does, not noticeable.

Good to see another Canuck around here. Many years ago, when I researched the price of standard glass 3/4" 96ishx30ish I think it was around $300. I would love to go Starphire, but I hear it's 3x more. May I ask how much you paid for 3/4" laminated Starphire and why laminated over solid 3/4"?

TIA,

James

Sorry so long for a reply, I dont want to take from Del`s thread at all, but to answer your questions.

It was about 600 and i think 250 for the side window.
Laminate was used becuase starphire is not manufactured thicker than 3/8...so using two i end up slightly thicker than 3/4"

The lamination is 100% invisible if done right, and still no where`s near comparable in clarity to standard plate, im very happy i went with it.

The step down in the perimeter brace was because this is where any twist or bow would want to occur...i left a measured gap between the wall and this brace, so there was a measurable space i could see any bowing when i was going to fill it.
No measureable bow has occured over a year later.

That brace was installed purely for piece of mind...but for the cost of a bigger sill and a couple of 2x4`s, i decided it was a good idea.

Marc.
 
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