View Full Version : Centerbrace cracked/broken

08/21/2006, 07:49 PM
Hey everyone, I came home from the meeting to find that one side of the centerbrace that goes down the middle of my 90gal has completely cracked/broken off. Now I don't know too much about this, but is this going to be a real big problem? If so is there any way to fix it?


And thanks again everyone for the frags! All of them are acclimating right now. Thanks for the coral/lr pieces too. They fit nicely into the tank. I can have colt coral frags ready in a few weeks if anyone wants one.


08/21/2006, 08:34 PM
My pleasure Chris, hope it helps to fill up the tank and build you an awsome self contained reef.

Hmm a quick fix would be to take two stainless plates 316L grade and weld them to a large steel threaded screw (also 316L grade). Basically like a large C clamp, pivoting on each end preferably. I would only tighten it up enough to just meet the frame to hold in place. Any excess pressure would also cause the tank to break which your trying to avoid.

You could try gluing, cementing or even plastic welding the original piece back on but I think structurally it's not going to help?

08/21/2006, 08:48 PM
Yeah my dad broke it before and he had used some special glue that was supposed to hold several hundred pounds of pressure.. It lasted a few weeks.

I myself would rather not mess with it as I have no experience with that and would probably just make the tank break haha. But what you said is pretty clear, I can tell my dad tomorrow and hopefully get the supplies then.

Is this something that needs to be done ASAP? My schedule is some what busy but if its something that needs to be done right away I can make time one way or another.

08/21/2006, 09:45 PM
Immediately? Hmm not sure to be honest.

My opinion (FWIW) would be it should be ok but I wouldn't let it go for too long either.

My 90 has no middle supports but the tank was also built in 1985 so I dont' know if the dimensions have changed since then?

If your not sure, I'd contact the manufacturer to see how dependent your tank is structurally on that brace.

08/21/2006, 09:54 PM
Sent an email to AGA. The only way I found to contact them. Well there isn't much I can do about it tonight. Thanks for all the advice!

08/21/2006, 09:58 PM
Oh Boy!! Yes Chris, it can be a big problem. the tank glass could fail if bumped the wrong way. the brace prevents the long side glass plates from bowing out too much from the weight of the water inside. glass can bend a little, but its not too flexible or forgiving.
take a look down the length of the front and you will see some deflection. that puts lots of stretch type stress on the outer surface and compression on the inner. the brace is there to retain the normal empty dimension across the top. I believe the plastic used is polyproylene, and not much glues to it. although there is one new glue made to hold them. MadtownMax did the same repair on his 65. if we can get hold of him he could tell you where to buy the glue.

otherwise, WDS will have to do some 316L stainless steel welding to make a brace for you, since he's the only one of us qualified to do that. but other stuff can be used to make a brace to restrain the spread of the top tank walls. see what you have.

08/21/2006, 10:07 PM
Hmm well I looked at the tank.. not much bowing yet, a little I think. The only way I could tell was to put my eye next to the side of the tank and look all the way to the other side of the front. I know there is a slight bit because the cracked part of the brace is several mm away from the other side of the tank.

I'm currently looking through the basement to see if I can find anything that will do for the time being...

EDIT: Not sure if there is bowing or not, half the time I see it, the other half I don't. I may just be seeing things but I'm not sure.

08/21/2006, 10:21 PM
trust the gap in the break , that is the bow. thats enough. its not going to look like a wide left hand turn.

08/21/2006, 10:29 PM
I snapped a picture. And well I couldn't find anything to make a little brace from in the basement.. maybe I'm not being creative enough, and I could make one of sturdy wood pieces for the time being, but now sure if that would work, plus it would require a bit of sawing and hammering haha and the rest of the family is asleep..


08/21/2006, 10:39 PM
No, wood is too soft and flexible and expands ,contracts with conditions. Yup , same kind of break Nick had. To repair, when you find the right glue, you will need to drain the tank down to close the gap, then glue something like a splice of 1/4 inch acrylic over it.

or a tensioned cable perhaps with clasps to grip the frame.

08/21/2006, 10:40 PM

Get some 1/4" (not 1/8") acrylic from Sears hardware - you might be able to find a scrap piece that will work for about 50 cents (you'll want something at least 2" wide, and long enough to span the gap)

I then used your standard super glue (cyanoacrylate) glue that came in a special pack with a *plastic activator* this is key to get both plastics to melt together - I coated both surfaces with the activator, then put super glue on one surface - you can cut away the brace after the taper at both ends, and use that area with the taper to get a good bond at both ends of the replacement acrylic brace.

I'd suggest using a clamp to hold the tank (or just to drain it when you're doing the gluing) to make sure that it stays put for a good 24-hours (yeah, it's over-kill, but always good to be safe).

If you want a picture - I can take one as I now have my tank again (movers delivered it yesterday :thumbsup: )

BTW - Ken - I didn't break my brace, I cut it out so I could use just one halide in the middle without the shadow of the original brace. Sorry; no pictures of the new 120, it's only 1/2-filled ATM- I'm waiting to make enough RO/DI :lol:

08/21/2006, 10:44 PM
Oh, I forgot to ask. what might have caused the break in the first place? is it a new tank or a used tank? do you have all the rock piled against the back glass? rock shouldnt lean to heavily against the glass. it adds a lot more weight than just the water. it can shift on the sand and lean heavily on the glass.

08/21/2006, 10:51 PM
A picture would be awesome.

Looks like I have some things I need to get a few things tomorrow. I have acrylic, but unfortunately its 1/8". So then I need the super glue that comes with a plastic activator? I'm guessing I can get that at a hardware store too? Or maybe my dad has some in his workbench.

Edit: What caused the break in the first place was my dad not thinking:rolleye1: well I was at work and he wanted to move the tank. So he tried grabbing it by the center brace, after I told him not too >.< . But then what kind of glue was it? Marine glue or something like that. We glued the cracks and sent the tank on its side so that the cracks were pushed together again. It held for a few weeks, until now anyway.

08/21/2006, 10:52 PM
Yo! Madtownmax to the rescue!!

sorry, forgot why yours needed glueing. I've never seen a cyanoacrylate with plastic activator around here. but of course, never looked? where to buy? the brand? how can Chris find some?

as for 1/4 inch acrylic, I have some and can cut any size you need Chris. just say when.

Hey Nick, are you setting your tank up in the window with the lake view, for the fishies?

08/21/2006, 11:02 PM
Hmm didn't find any of the glue in my dads workbench, the only thing I could find was something called J B Weld. Its a cold weld. Not sure if that would work for anything though? Maybe someone else would know?

08/21/2006, 11:14 PM
I've used J B Weld before, it bonds many things, but not sure about the type of plastic that tank frames are made of. it needs to be melted, or disolved, to bond. finding the activator MadtownMax is talking about is the key.

oh, I just checked the garage, i have a carpentry clamp that will reach across the tank and cinch it in for the bond. so you can drain a little water until the crack closes, pretty close, then tighten down the clamp to prevent deflection while the glue cures.

08/21/2006, 11:18 PM
It was superglue brand glue - it came in a special pack with the activator - I got it at sears hardware in Newark - college square shopping center.

I was given the tank like this from the previous owner (with a 1/8" brace that had streched) so I replaced it with the 1/4" acrylic brace - then went back and cut out a little bit more (which isn't really necessary -I just did it for more light penetration)


08/21/2006, 11:23 PM
I may just have to stop by tomorrow to get that clamp then, and possibly acrylic if we don't have 1/4" somewhere in the basement. I am going to go to bed now. I'll check this and update if need be tomorrow morning. And it looks like I will need to get this all done before work haha.

08/21/2006, 11:26 PM
Yo-k RBTA! sending PM for AM>

08/22/2006, 09:52 AM
Well no change so far. The crack is the same width apart as it was yesterday. I can't do anything about it today but I'm free enough to get it done tomorrow hopefully. I may be able to check the Hardware store next to my work for the glue.

08/24/2006, 03:48 AM
Your probably at your stress limit or very close to it so you won't see much more seperation in the gap. The next seperation would be the collapse of the tank. I'm not saying thats what's getting ready to happen.
Nicks idea sounds good but you will have to get that clamp as he and Ken suggested. The only way to check how much bow is in your glass is with a long straight edge such as a 2 foot carpenters square. Measure out the largest area of gap from the area with the straightest edge and that will give you an approximation of how much the glass is bowed. I wouldn't think it'd be much more than a 1/16" at it's worst point or even less but that's enough to cause problems.
I'm not sure how Nick did his tank but I'd seriously consider using some wood pieces to go between the clamp contact area and the tank or frame surface. DO NOT OVERTIGHTEN EITHER!!!

08/24/2006, 01:57 PM
I think nick repaired his tank empty, no load. that way the glass was in the normal flat , un stressed state. then the strap would take the load when you fill the tank. to use a clamp i would spread the load on both sides with a couple pieces of wood. so as not to point stress the glass. and yes, do not tighten too far with the tank full.

08/24/2006, 04:13 PM
<a href=showthread.php?s=&postid=8005121#post8005121 target=_blank>Originally posted</a> by kaptken
I think nick repaired his tank empty, no load.

this is correct

08/24/2006, 08:09 PM
Well I think I found glues that might work.. My dad has 2 Ton Epoxy glue. But no place I can find has 1/4" acrylic. The hardware store near me only has 1/10". So I'm hoping to get that all worked out tomorrow. And I do plan on draining the tank beforehand.

08/24/2006, 08:09 PM
Well I think I found glues that might work.. My dad has 2 Ton Epoxy glue. But no place I can find has 1/4" acrylic. The hardware store near me only has 1/10". So I'm hoping to get that all worked out tomorrow. And I do plan on draining the tank beforehand.

08/24/2006, 08:09 PM
Well I think I found glues that might work.. My dad has 2 Ton Epoxy glue. But no place I can find has 1/4" acrylic. The hardware store near me only has 1/10". So I'm hoping to get that all worked out tomorrow. And I do plan on draining the tank beforehand.

08/24/2006, 08:59 PM
we read you the first time:D
and the second time:D
and the third time:D

btw...i know lowes carries 1/4" acrylic. its about $12 for a large piece...if i remember the piece was about 30" x 30".


08/24/2006, 09:36 PM
Ok thanks, I'll probably check out Lowes tomorrow then.

08/25/2006, 12:24 AM
I'd be careful for anything other than a plastics-specific adhesive - one piece you know is acrylic (and finding something to actually glue acrylic is hard enough)

as for the tank frame - I'm going out on a limb here, but I'm guessing it's some type of colored polycarbonate (or PVC - Polyvinylcarbonate- same as the stuff we use for plumbing)

If you've ever worked with either, you'll know that you use a specific epoxy for each, as the epoxy actually breaks chemical bonds in the plastic and welds the pieces togather - so you basically need a *solvent* that is specific to the bonds you want to break.

Superglue is cyanoacrylate - acrylic with a volitile component that evaporates away, and leaves a type of acrylic behind to bond the pieces - however this does not *melt* the acrylic on it's own - that's why the plastic *activator* that came with the specific superglue package that I found was so important, as it softened (chemically melted) both the acrylic, and the aquarium's plastic frame so that the superglue could actually melt into each plastic a little bit for a super-strong bond.

The two-part epoxy that you have may work, but I think they make one specifically for plastics that may work even better (the epoxies are usually used to bond rough surfaces where they can physically hold the pieces togather, not chemically bond them) - so I still can't gurantee that it will hold forever; that's why I'm recommending the superglue pack as I can tell that the bond that I made is a permanent bond.

It is also possible that one of the Weld-ons may work also (like weld-on 16 that people use to build acrylic tanks) - this stuff is as thin as alcohol and is basically just a plastics solvent)

Weld-on makes a variety of plastic adhesives, but they can usually only be found at plastics-specific vendors or shops, not your local hardware store or home-depot :(

If you get a chance, try calling sears hardware in college square (behind the Newark public library) and see if they still carry the superglue pack with the "plastic activator" for plastics - if they do, that would be your best bet - and they have 1/4" acrylic too :)

08/25/2006, 07:44 PM
Hello Chris and Nick. I followed up on your info Nick and dropped by the University plaza sears tonight after my weekly ATM stop down the road. GOOD NEWS Chris, they have a couple suitable scrap pieces of 1/4 inch acrylic in their scrap bin marked for less than Five Donaro.. then i looked for Nick's super glue with activator. They didn't seem to have a two part, but they have a new one part tube that glues all plastic, including the impossible to glue polypropylene. It's called, get this, GRIP-TON-ITE by DEVCON. Quick drying, but still let it cure over night. they don't give a break strength, but in this application not much is needed. but bonding is essential. looks like its worth a try. the pack looks like this. i think its the clear, they have black auto plastic grip=ton-ite too. I bought a tube for home.


better living thru chemistry!! hey, this DIY site looks promising for other stuff and parts. i have to explore a bit.
hope this takes care of the problem.

08/26/2006, 08:39 PM
Tank is drained, brace is glued with acrylic, clamp is in place. Everything is happy in buckets being aerated and heated. When I get home from work tomorrow everything should be good to go. Only thing that stinks is I had tear down my rock work, but it gives me a chance to aquascape a bit more.

08/27/2006, 06:28 PM
Tank is filled up and the fixed brace is holding great. But the next few days will tell if it will stay or not.

08/27/2006, 06:53 PM
That's good news. let us know if that new glue does the trick. I'm sure lots of other people are looking for a good repair glue for tank braces. I bought a tube, but haven't tested it yet.

08/27/2006, 07:31 PM
We used Plastic Weld I tihnk it was. One container was the glue, the other container attached to it was the activator. And you just mixed it to get it to work. Looks good so far but Im still crossing my fingers.

08/27/2006, 08:19 PM
Ahh!! Another glue i hadnt heard of . where did you get the plastic weld and activator? and whats the brand name.? might as well fill us all in for the day we break our tanks..

learn something new everyday, i say...
keeps the cobwebs away!

08/27/2006, 08:48 PM
It didn't say it was an activator, my dad just called it that, or it works as an activator. I saw some at True Value, my dad also picked up some at the Sears Hardware store. We used it all and threw it away so I can't give the brand name 'cause I forgot.