Building a Large Acrylic Tank - Questions and Build Thread

Eagle_Steve · Aug 1, 2022

NigeltheBold said:
What about Weld-On #40? I've heard of some people using that instead of #3/#4/#16 because it's a lot stronger.

Never used it so cannot comment on it.

Aardvark1134 · Aug 18, 2022

Building an acrylic tank is nothing like building a glass one. I highly
recommend you have someone who is used to making large acrylic tanks make it for you. As for thickness my 360 only needed to be 1/2 inch but I upgraded it to 3/4 just as overkill and despite being 8 ft long there is almost no flex at all.

NigeltheBold · Aug 18, 2022

Aardvark1134 said:
Building an acrylic tank is nothing like building a glass one. I highly
recommend you have someone who is used to making large acrylic tanks make it for you. As for thickness my 360 only needed to be 1/2 inch but I upgraded it to 3/4 just as overkill and despite being 8 ft long there is almost no flex at all.

Appreciate the advice. Did you build yours? If so, what kind of bonding cement did you use?

Aardvark1134 · Aug 18, 2022

NigeltheBold said:
Appreciate the advice. Did you build yours? If so, what kind of bonding cement did you use?

I did not build mine I had tsunami at fish tanks direct build it. Building a glass tank is simple and just some easy math. Acrylic is not simple. For example all but the largest glass tanks don't tend to have euro bracing. But every acrylic tank of any decent size should.

albano · Aug 18, 2022

Aardvark1134 said:
I did not build mine I had tsunami at fish tanks direct build it. Building a glass tank is simple and just some easy math. Acrylic is not simple. For example all but the largest glass tanks don't tend to have euro bracing. But every acrylic tank of any decent size should.

I also used fishtanksdirect for my 200 & 500g acrylic tanks… would use them again without hesitation!

Aardvark1134 · Aug 18, 2022

NigeltheBold said:
Not really sure what you're referring to... I'm not talking about a professionally built acrylic tank. I'm talking about methods used to bond and seal acrylic when building a tank at home.

Are you saying that I shouldn't need silicone sealant if I use a proper bonding agent? I thought both were necessary, but maybe I'm wrong?

Silicone will not hold on acrylic worth poop
Go to 6:58 in this BRS video Silicone should not be anywhere in an acrylic tank.

NigeltheBold · Aug 21, 2022

Aardvark1134 said:
Silicone will not hold on acrylic worth poop
Go to 6:58 in this BRS video Silicone should not be anywhere in an acrylic tank.

Yeah, I will be using Weld-On #40 for bonding & sealing. No need for silicone.

Arthurfarris · Aug 27, 2022

When it comes to durability, a glass aquarium will last longer compared to its acrylic counterpart. Acrylic materials do not have the ability to stand UV light which can affect their longevity. The effect is that the acrylic will become brittle and yellowish over time. You will know that an acrylic aquarium starts to break down when it becomes yellowish. This situation is the effect of all the UV lights it received coming from the aquarium lights and even the sunlight.

Aardvark1134 · Aug 27, 2022

Arthurfarris said:
When it comes to durability, a glass aquarium will last longer compared to its acrylic counterpart. Acrylic materials do not have the ability to stand UV light which can affect their longevity. The effect is that the acrylic will become brittle and yellowish over time. You will know that an acrylic aquarium starts to break down when it becomes yellowish. This situation is the effect of all the UV lights it received coming from the aquarium lights and even the sunlight.

Not correct acrylics that are used in tanks these days are treated for UV exposure and have even been left out in desert sun for over a decade in the case of some brands. Also 99% of what the saltwater industry calls uv is either just straight violet or barely into the UV spectrum. You will be resealing a glass tank long before a well made acrylic tank would ever be effected by UV.

albano · Aug 27, 2022

I have a couple of 120g acrylic tanks that are from the 90s… I dare anyone to find any difference from my newer tanks!

Big Smelly fish · Aug 27, 2022

My reef tank is 29 going on 30 years old, still looks great. I e we I’ll take acrylic over glass any day. I have more glass tanks. A friend of my own a LFS and all his tank are acrylic part of the same group my tank came from and 29 years also and all look great also.

albano · Aug 27, 2022

I’ve said this many times on multiple forums… most people that don’t like acrylic, have never had one… those that love acrylic have had glass, but have no desire for another glass tank.

Celestion · Aug 28, 2022

heavy acrylic aquariums use 1/3 less heater energy much stronger leak less , the larger the tank the more plexi gains advantage , . there is a acrylic master from Seattle here on reef2reef somewhere ( someone might help) , I agree with a previous post look for the most experienced aquarium builder u can find , 3/4 is the minimum on a 300 , 1 inch is better , and get 3/4 top and bottom plates , 1 inch is better , often builders thin it here to save cost,

NigeltheBold · Aug 28, 2022

Appreciate all of the input. This won't be a reef tank, so lighting won't be very strong anyway. And it'll be in a basement, so there won't be much sunlight from windows or doors. The whole reason I wanted to build it myself was because it'll be in the basement and I don't think anything this size would fit down our basement stairs. So I figured I'd take the panels down, one by one, and assemble it down there. When it comes time to remove the tank, I'd obviously have to cut it up into smaller pieces. I need to go with acrylic because I'm worried that the tank could be bumped into by kids in the future, and I really don't want to have to worry about glass breaking (what a disaster that would be).

Unfortunately, I tore my ACL and had to have knee surgery last week. Recovery takes several weeks at least, so this project is on hold for awhile. Maybe I can revisit it in the fall or around the holidays. The goal is to have a large fish/predator tank, with a bamboo shark, maybe a ray, and some larger fish that wouldn't work in my reef tank. I'll start a separate build thread when I actually get around to doing it, but the plan is to use 3/4" acrylic, bonded with Weld-On #40. I'll be installing 6" or 8" cross bracing strips all around the inside perimeter and across the top, since I don't have a way to cut euro bracing with curved inside corners myself (I can't find anyone local who will do it either). If anyone knows of someone online that could cut a custom Euro Brace top for me, I'm all-ears.

MarcusH · Aug 28, 2022

albano said:
I’ve said this many times on multiple forums… most people that don’t like acrylic, have never had one… those that love acrylic have had glass, but have no desire for another glass tank.

I've had both and prefer glass only because it's easy to scratch acrylic. Anything thats not a display I much prefer acrylic though.

albano · Aug 28, 2022

MarcusH said:
I've had both and prefer glass only because it's easy to scratch acrylic. Anything thats not a display I much prefer acrylic though.

I hear you….but acrylic scratches can be buffed out!
It’s also fairly easy to avoid most scratches.

MarcusH · Aug 28, 2022

NigeltheBold said:
My only concern is that this stuff is a bit thicker than #3 or #4, and I'm not sure how to handle the excess that will inevitably squeeze out of the joints when I glue them together...

The weld on I've always worked with was solvent thin. It melts the acrylic to bond it together, not like glue.

I used sewing needles to separate the two pieces, put the weld on between with a syringe to melt the acrylic, then removed the needles to drop them together.

Thicker might be easier to work with in some ways.