top brace cracked on 600 gal acrylic help!(photos)

reefkoi

reefkoi

Premium Member
I was cleaning today and noticed the top brace is cracked. The tank is a 600 gallon ATM built acrylic. It was built august 2005 the dimensions are 96"x48"x30"tall all 1" acrylic except for the top and bottom, they are 1/2" thick. I always wondered why they used such thin material. Now its cracked along the edge from the start of the brace towards the edge of the tank. About a 6" crack.
The top is bowed up some, from the heat generated I am guessing. I think this means its not spreading open otherwise it would be bowed down?
I am looking for an opinion of a tank builder or something, I dont want everybody to chime in and just cause me panic, I need someone with experience here to give me advice on what to do next. Ofcourse I am calling them on Monday but I dont know what they will say and would like a 3rd party opinion.
heres a shot from far away to show you where the crack is. its on the long side of the tank about a 1/3 of the way right in the corner of a brace cutout.
crack1.jpg
[/IMG]
heres a close up shot


crack2.jpg
[/IMG]
 
I would get it fixed ASAP. imo, it was caused by too small of a radius on the corner. It should have been at least 3/4", but it looks to be less than 3/8". Also, it looks like you have your lights situated fairly close to it too.

Can you get a clamp on it from front to back? This will stabilize it and take the strain off of the top. his will need to be done when you repair it anyway, so try to do it now.


Definitely fixable without draining the tank, but those tight corners are a definite potential for more problems.
 
so do you think just gluing it back together will work? It seems tight can i clean it and use superglue? or does it need to be a special acrylic glue?
 
You need a very large clamp to make sure the chemical gluing takes. Got any acrylic tank manufacturers in the area? They would most likely already own the equipment and might be cheaper and give you more peace of mind that a DIY in this case.
 
If you REALLY wanted to DIY, I would get some tiny acrylic scraps or acrylic dust and put it over the crack then weldon the crack.

Note: Put somthing under it so weldon doesnt get in your tank.
 
o.k. I have a guy in our club that does acrylic i'll ask him if he can glue it. I just wish I knew what caused it? too thin? or heat? both?
chris
 
It may just be chronic stress. As AcroSteve said, the corners of the cutouts are high stress areas. The larger the radius at the corner the better. From your pictures, the radius looks really short. The radius at the corners of the cutouts on my 120 are 1". For your size tank, I would have considered 2" radius in the engineering of the tank especially given the highth of the tank and thickness of the top material.
 
nice, I looked at the CAD drawings of my tank and they never even submitted the top design to ATM. They detailed everything else out but left the top design up to the tank manufacture. So I would think this is ATM's fault. I would have thought such a huge tank building company would know this?
Yes they are small radiuses, makes sense. I'll let you guys know what the company spokesperson says tomorrow!
Chris
 
Excellent article on wetwebmedia. Thanks, that helps a lot, although I dont have any bulbs on top of the braces. I think the small radius may be the culprit here. I wonder if anyone is going to take the blame for this? I would guess the guy that drew the CAD design and sumbitted it to ATM?
 
sounds like your builder was skimping on costs, theres no reason to make the top and bottom 1/2" mines half inch on a 120
 
yeah my 180 had 1/2" top and bottom. A friend of mine had ATM build him a 600, he got a 3/4" top and bottom. So I am going to see if they know why i got a 1/2" top and also bring up the small radius cutouts. See if they have changed this design? or what.
Chris
 
Same exact thing happened to me on my old acrylic tank. The company I bought it from built a replacement tank and charged me cost.

The crack on mine was in the exact same place, it was caused by heat and stress on that area.

I feel for you man, it freaked me out!!

Get some weldon and clamp two pieces of acrylic between the top and bottom part of the crack. And also fill the crack with weldon. Clamp it hard for a day and you should be OK. Also, make sure the crack does not start developing on the front panel piece. Mine did, so watch for it.....
 
I also have never understood the concept behind building these acrylic tanks.

Some manufacturers

-use smaller top/bottom vs sides
-gusset corners
-use larger top then sides/bottom


I just measured my 260g & the sides/bottom are .5 in & the top is 2 layers of .5 in. They also glued strips in each seam which is suppose to be similar to gusseting.

I just wonder why manufacturers do things so differently, is it just pricepont??

Anyways, PM acrylics on this forum. He will be able to give you suggestions
 
Using 1/2" acrylic on the top, they really skimmed out. My 375 Tenecor which was 96*30*30 had 3/4" all around except for the bottom since the bottom is only designed to transfer load. I can't belive they used 1/2".


I would call the manufacturer and start looking for a good acrylic guy locally.
 
I had the same thing happen to me, only at a corner brace. Here's the thread.

http://reefcentral.com/forums/showthread.php?s=&threadid=453545&highlight=bezoar

Just be careful if you use braces on a cracked tank, as was pointed out to me. The link in my thread no longer works but the guy tried metal braces to support his tank while he repaired it. As he tightened it the crack broke loose and started dumping water all over his floor.

You could PM acrylics, he's a tank manufacturer and really helpful. Sounds like you need a new one. How long is the warranty on yours? You could use weldon to sandwich two square pieces above and below the crack as a stopgap, but I wouldn't trust that long term. Also any repairs you attempt may void the warranty.
 
I called ATM they were surprised it cracked (could have guessed that ;) ) they sent out an acrylic piece and some weldon. I had a friend bring over another piece and we sandwiched them top and bottom and clamped. Its solid, and I noticed the crack never made it to the edge, it stopped about 2" from the edge.

I have now changed out all my lights to lumenarc stealth fixtures. This way no lights are above any portion of the acrylic, that is what caused this, and I did increase my photoperiod before the break happened which I think pushed it over. The area of the crack was always hot, its something I always hated about the lamp housings I bought but you know how it is, there are always things about a tank you want to improve, however I didn't know how serious heat and acrylic are.

I spoke with a Denver club member that has a 600 with a 1" acrylic top, he has a crack also. So I'm not sure that 1/2" is that bad, its just the heat that is really the killer. 250 W d.e. bulbs at a height of 6" above acrylic is bad news.
thanks to everyone for the help and the link to wetwebmedia really helped I like that article, good info for acrylic tank owners!!!
Chris
 
I am with z28pwr. I have a 525 (120*48*24) from Tenecor with 3/4" all around with 1/4 black on the inside sides and back. I also have a 3/4 " top and bottom. It all depends on who makes your tank.

Vic
 
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