External overflow and acrylic bowing

[Tron87]

I'm installing an external overflow on my tank. The tank and overflow are made of 1/4" acrylic. The back of the tank bows when it is full of water which makes me worry about the external box being pulled off when I fill the tank up. The tank is 50 gallon and the face in question is 24"X24" Square.

The box is 12" long by 5" x 5". What I did was glue a 1 Inch thick piece of acrylic along the face of the box that will be against the tank back. This gives me 22"X1" area glued agaist the tank rather than 22"X1/4" glued agaist the tank.

I used a two part plastic epoxy rated at like 800 PSI and then sealed all the joints with a silicon aquarium sealant rated pretty high as well.

Do you guys think this will hold that area of the tank so that is does not bow and pop the overflow box off? Or should I glue 1"X 1/4" thick acrylic braces vertically up th length of the tank on each side of the box as well?


If you guys think some pics will help then I will get them as soon as the epoxy dries on the box.:strooper:

 

[Tron87]

Pretty please. My fish need their new skimmer.

 

[shag26272]

your acrylic is too thin, why is it made out of 1/4 inch? I think you need 1/2 in. acrylic for a 24 in tall tank

 

[Tron87]

I think the thickness is due to the shape. It is a corner tank so the biggest face is 24" x 24". On the other hand there is quite a bit of bowing. The tank is a TruVu tank. I've never looked into the qualiy of that particular brand but its a fairly old tank. Probably at least ten years old, maybe more.

I sure hope its not time to juts go get a new rectagular tank. I like the corner shape because it allows me to have less lights concentrated on a smaller area.

Any opinions on the overflow box problem though?

 

[Untamed12]

I'm trying to visualize what you are doing there...Since the overflow box is acrylic, you should just bond the box right onto the back of the tank. You don't need 1" thick acrylic!

By doing that, you will have doubled the wall thickness of that area of the wall, which might minimize the bowing you are getting along the back. If the backside is not used to view through, you could carry this to the extreme by simply bonding an additional piece of acrylic to the entire back side. A 24" square piece of 1/4" or even 1/2" acrylic would not be very expensive.

When you refer to two part epoxy and silicon you've lost me. You wouldn't use those materials with acrylic. You should be using an acrylic bonding agent like Weldon...

 

[Tron87]

I dropped the box off at the LFS so he could drill the hole for the drain so I can' get pics now.

Picture this. I have a box with no top an missing one side. (I don't mean to talk down or anything I just want it to be clear) If I placed it against the tank it this state then the 1/4" thick sides of the Acrylic would be aqainst the tank. This gives my a length of 22" of acylic (12" long + 5" high + 5" wide) that is 1/4" thick.

Now what I did was cut 1" wide strips of the acrylic and glue them onto the edges of the box that would have come in contact with the tank. It is like I added a 1" widde flange to the box so that the contact suface area is much greater.

I hope that cleared thigs up.

I used a two part epoxy from LocTite to put it together. I looked for something that I thought might wor better but Lowes seems to have failed me. The backage said it could be used on PVC as well as most hard and soft plastics. I used silicon to seal up over the glue because it made me feel better.

If you think that I should just rebuild the whole thing with weldon then I think I may have enough acrylic left but cutting it with my sabre saw is the worst.

Might I be able to get some Weldon and use that for the actual overflow to tank bond? That is the one that will recieve the stress.

PLease give me feedback as I hope to be drilling and plumbing this weekend.

 

[Tron87]

And where should I look to get some Weldon?

 

[BeanAnimal]

I would start over with the overflow boxes.

The EPOXY is simply not suitable for what you are trying to do.

You should build the box using WELD-ON solvent cement and then bond it to the tank using the same cement.

There is no need to have the 1" flanges either.

Think about it, you glued 1/4" acryic to 1" strips to glue to the back of the tank. You STILL have a 1/4" piece glued to flat piece of acrylic... in other words it is the same joint as it would be on the back of the tank.

Bean

 

[Tron87]

If I can break my box apart should I just sand the epoxy off and start Weld-on-ing or use my extra acrylic. I really really don't want to do that cutting again.

but maybe somethings can't be avoided.

 

[shag26272]

this is where I got mine


http://cgi.ebay.com/ws/eBayISAPI.dl...MEWN:IT&viewitem=&item=200080257248&rd=1&rd=1

 

[Tron87]

O man do I Feel dumb. I got the box back and its drilled which is great. but the pet store guys broke a side off while drilling it. I can chip off the epoxy with my fingernail. LocTite my ***.