How bad is my idea?

jlames

New member
I'm new to the forum so thank you for any help you can offer. How bad is my idea of using a piece of 1/4" acrylic, or any thickness for that matter, to repair the bottom of a tank. There is some crazing in the bottom acrylic piece which may be the source of a leak and my thoughts are to laminate an over-sized piece of acrylic, overlaying the crazing by a couple of inches using Weld-on. In my mind, the fusion the Weld-on creates between the tank bottom and the new laminate should seal the crazed area off from water intrusion in much the same way as a patch on an inner-tube does.
 

m0nkie

Active member
Even you used "Should"

Which means there might be a chance of leak. I wouldnt risk it. Specially at the bottom. It will be alot more work to replace when your tank has fish and corals inside

In this hobby, you try to do everything to prevent a flood.. you will see when you start designing sumps
 

Lazhar

New member
You should post a picture of the problem area to have a better idea. But remember that the acrylic has to hold the water and the weight of the water so its no only to keep the water from leaking but holding the tank from splitting open.
 

sfsuphysics

New member
For an acrylic tank the entire bottom should be supported anyways, so I would absolutely have no issues laminating acrylic to the bottom. I have done it all the time to patch holes from closed loops that I didn't want, granted the acrylic used is as thick as the bottom (or thicker), but if there are no holes and it's just crazing, shouldn't be an issue.
 

Lazhar

New member
I am not an expert on this but that doesn't look too bad. I think you can do what you said. Just add a piece of acrylic on top of it. I would use thick acrylic and weldon 16 it will cover better the little cracks. How many gallons is this tank? How tall?
 

Macimage

Active member
Hi everyone,

jlames is my husband and he is trying to fix my tank.

The tank is a standard 225 gallon, 72" long, 30" high and 24" wide.

Thanks!
 

Mrramsey

NEO Reefer
I look at it like this...

If it were a bridge and the underlying structure was cracking I don't think I would repave it and call it good and drive on it.

That being said I am not an acrylic guy...
 

Lazhar

New member
Hi everyone,

jlames is my husband and he is trying to fix my tank.

The tank is a standard 225 gallon, 72" long, 30" high and 24" wide.

Thanks!


No I wouldn't fix such a huge tank! Thats a lot of water weight 225x8 lbs of water without counting the rocks!!! I though we were talking about a 45-65 gallon tank.
 

m0nkie

Active member
like i said, weight in the future risk factors.. specially at the bottom of the tank. If it cracks in the future, you have to remove all your rock, sand, fish, coral, everything!

it definitely sucks.. 225gallon is quite expensive. maybe find a professional acrylic shop and have them cut the bottom and reseal a brand new one? not sure if that will work.
 

sfsuphysics

New member
I look at it like this...

If it were a bridge and the underlying structure was cracking I don't think I would repave it and call it good and drive on it.

That being said I am not an acrylic guy...

Well there's your problem, you drive on cracked bridges all the time it's the concrete/asphalt decking, and yes they patch those up all the time a bit cheaper than replacing the entire deck. The bottom of a tank is not meant to be structural, which is why you need a solid sheet of plywood under it. It's a bad idea to support an acrylic tank just by it's edges like you can get away with on so many glass tanks. Now if the steel girders and what not that actually support the bridge are cracking.. then yeah I wouldn't want to drive on it either ;)

The bottom of an acrylic tank really has one purpose, to hold the sides of the tank together. There's no downward force on it that is unbalanced, unless you put it on a way wrong type of stand.
 

Mrramsey

NEO Reefer
Well there's your problem, you drive on cracked bridges all the time it's the concrete/asphalt decking, and yes they patch those up all the time a bit cheaper than replacing the entire deck. The bottom of a tank is not meant to be structural, which is why you need a solid sheet of plywood under it. It's a bad idea to support an acrylic tank just by it's edges like you can get away with on so many glass tanks. Now if the steel girders and what not that actually support the bridge are cracking.. then yeah I wouldn't want to drive on it either ;)

The bottom of an acrylic tank really has one purpose, to hold the sides of the tank together. There's no downward force on it that is unbalanced, unless you put it on a way wrong type of stand.

Yes I was meaning it in a structural sense. But that being said I am pretty anal about some things and just knowing that those cracks were there would drive me nuts even if I patched over them lol.
 

NanoReefWanabe

New member
i am not an acrylic guy either, but i was always under the impression that crazing was a sign of stress in the plastic and adding any sort of weld-on type product would only amplify the crazing and make it worse…

i would have to agree with the person who suggested to have someone cut the bottom of the tank off and replace it…a couple hundred bucks of acrylic to replace the bottom seems a boat load cheaper then the 10's of thousands of dollars damage a failed 225 would create.
 
Top