Acrylic thickness - 375 Gallon Build

richamc01

richamc01

Member
I want to build a 375 gallon tank in the future and I'm looking at acrylic prices now. The demensions of the tank will be: 96x30x30 (LXWXH). The tank will be separated into three separate "chambers". Saltwater, brackish, freshwater. The dividers will be at 32". Making the "chamber" 32x30x30. I'm curious as to what thickness the acrylic will need to be. I know that anything over 24" tall should be 3/4" thick but since I have the dividers, they should provide some bracing right? I also plan to do some bracing around the top as well but I'm hoping to use 1/2" or even 3/8" to save some $$$$.
Thoughts?
 
snakeblitz33

snakeblitz33

Well-Known Member
I have not done alot of acrylic work, but im certain that since your height is 30", regardless of the width and length per section you may not want to use less than 1 1/4" thick acrylic. Using less at that height can cause major bowing which in turn can cause seam damage and leaks.
 
2quills

2quills

Well-Known Member
Looks like builders typically go with 3/4" for this size tank. I would consider that a minimum and just think of the dividers as extra credit given the experience curve.
Sounds like a neat idea for a tank. If you like to keep a variety of tanks then why not have them all in one spot. Can't get much better then that for maintenance.
 
richamc01

richamc01

Member
Are you sure 3/4" is sufficient for 30" height?
This is where I got the height information. http://www.cichlid-forum.com/articles/diy_acrylic_aquarium.php
 
richamc01

richamc01

Member
Looks like builders typically go with 3/4" for this size tank.  I would consider that a minimum and just think of the dividers as extra credit given the experience curve. 
Sounds like a neat idea for a tank. If you like to keep a variety of tanks then why not have them all in one spot.  Can't get much better then that for maintenance. 
What if I were to knock the height down to 24"?
 
2quills

2quills

Well-Known Member
Quote:
Originally Posted by SnakeBlitz33 http:///t/395246/acrylic-thickness-375-gallon-build#post_3518622
Are you sure 3/4" is sufficient for 30" height?
That's probably a better question for the tank manufacturers. If you google the dimensions of the tank he's looking to build everyone is making them out of 3/4". But again, I would consider that a minimum. Going with 1" is a safer bet.
Quote:
Originally Posted by Richamc01 http:///t/395246/acrylic-thickness-375-gallon-build#post_3518624
What if I were to knock the height down to 24"?
Looks like they are still using 3/4" for that height as well. It's a gamble to try and build an acrylic tank yourself as it is. And unless I had professional tools and experience at my disposal than I would be real leery of pushing the limits and going with anything less then that. But it's ultimately your call. If you went with a 96x24x24 tank then you can make your top and bottom panels out of one sheet, and your front and back pieces out of one sheet instead of having to buy 4 full sheets and ending up with less leftover product after the build.
 
richamc01

richamc01

Member

Looks like they are still using 3/4" for that height as well.  It's a gamble to try and build an acrylic tank yourself as it is.  And unless I had professional tools and experience at my disposal than I would be real leery of pushing the limits and going with anything less then that.  But it's ultimately your call.  If you went with a 96x24x24 tank then you can make your top and bottom panels out of one sheet, and your front and back pieces out of one sheet instead of having to buy 4 full sheets and ending up with less leftover product after the build.
I very good point made indeed.
 
acrylic51

acrylic51

Active Member
3/4" is definitely pushing the limits IMHO.......Not sure what calculator you might have checked, but if it's Garf....Don't follow their recommendations.....You will have deflection using 3/4" material and that's without questions.....I'm assuming your talking about dividers going from top to bottom of the tank......I'm just briefly scanning the thread so please excuse any dumb questions I might ask.....From the pic shown in an earlier post the if that is a view of the top bracing you could see premature breakage with how the bracing is designed....Squared off corners would be a stress point. The corners on the bracing need to be a radius cut which isn't hard to do, but is the correct way, since that is where the stress or load will be distributed.....
Going with dividers top to bottom in the tank, I think you could do it with 3/4".......I think you'd be fine......Just using the dimensions you gave I'd feel comfortable doing it, but that also comes down to a couple key elements. 1 being excellent edge prep of your material and the other being your ability on good solvent joints......Definitely can be done.....
 
S

saxman

Guest
I agree with 2quills and acrylic51...you don't want to skimp with your material thickness, as all it will do is look bad down the road when it bows out, and may even fail on you.
FWIW, we had our tankmaker use 3/4" stock to build our 84" x 24" x 24" setup, and we'd have never gone any thinner based on owning several acrylic tanks.
 
phixer

phixer

Active Member
Hi Rich. You will experience some bowing and eventually may notice some crazing along the bonding lines but Ive seen many tanks of this height use 3/4" material. Personally, I would not build to these dimensions with 3/4" material. I would use 1".
Last week I picked up a tank 120 x 30 x 30 which uses 7/8" for the front back , top and bottom. Kind of odd?
 
2quills

2quills

Well-Known Member
Quote:
Originally Posted by Phixer http:///t/395246/acrylic-thickness-375-gallon-build#post_3519737
Hi Rich. You will experience some bowing and eventually may notice some crazing along the bonding lines but Ive seen many tanks of this height use 3/4" material. Personally, I would not build to these dimensions with 3/4" material. I would use 1".
Last week I picked up a tank 120 x 30 x 30 which uses 7/8" for the front back , top and bottom. Kind of odd?
They most likely didn't Polycast or Plexi-G then.. Probably used a cheaper import material as all the stuff is in metric, millimeters..
 
phixer

phixer

Active Member
Sorry, not trying to derail the thread but it's strange because the sides are just slightly thicker than 1.25" . A nice tank but a strange design.
 
acrylic51

acrylic51

Active Member
Odd 7/8" indeed......usually the only place you see thinner material used is on the bottom possibly.......
What the original poster is doing isn't IMHO a need for 1" material.....being there will be definite dividers between the sections....Would be nothing more IMO than a big display sump, but to separate fish types......So the tank height and length would be fine with 3/4" material.....Shouldn't be any crazy bowing or stress if properly braced up top.
 
phixer

phixer

Active Member






This is what a 32" column of water does to 1" thick acrylic over 3 yrs. This tank is 96 x 32ish tall x 48 wide (true height covered by wood trim), very similar to what your looking at but taller using 1". A nice tank (and sound I believe as long as the crazing dosent progress) but an example of what happens (advanced crazing) when building with material too thin IMHO. Sorry no photos of the top, the top is 1" thick with access holes cut out. Sorry for the top photo here, it wouldnt flip vertical. Hope this helps in your decision.
 
acrylic51

acrylic51

Active Member
What are we getting at here......First of all with a tank 8' long and 32" high 1" isn't optimal.......If you go back and reread what the guy asked before there is nothing wrong with his measurements using his suggested material thickness, because again the separate compartments will be fully supported, but will give the illusion it's all 1 unit......Your pics of an under built tank really doesn't give much merit to the question asked earlier......
 
phixer

phixer

Active Member
True, interesting to see field examples of how the material performs in a variety of applications. Took a look at a couple of 48" tall tanks today. One was a bowfront using 1" thick material and the seams looked pretty good. Forgot my camera so no pics sorry. The other was using 1.250" and had similar looking seams to the photos.
I like the thickness calculator on the Cyro site but do see the middle ground between what most Mfgs use compared to what is actually recommended.
 
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