Seam separation

6lkl6l24

Feeder Fish
Jan 27, 2020
3
0
1
34
So I have a 220g acrylic that is starting to weird me out. I know I need to replace it as soon as possible but will the bar clamps keep it from basically exploding from a complete blow out in the mean time? I know it won't prevent it from leaking.
Iv had the tank for years as saltwater and the tank has been pretty much the same seam wise since I got it used. A couple months ago I converted to an arowana tank and it was the first time it had been drained all the way down in years and as I was filling it back up I heard popping like crazy and the right side seam looked a little worse than before. No leaking at all though.

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dr exum

Goliath Tigerfish
MFK Member
Sep 29, 2007
2,930
3,531
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Northwest
Looks precarious,

If it were me I would drain it for sure, or have as little water as possible.

Get a stock tank or something if you need to house your fish temporarily

Good luck to you!
 

6lkl6l24

Feeder Fish
Jan 27, 2020
3
0
1
34
Well it would be for several months before I had the funds to replace. I planned on building a plywood tank over the summer anyway.
I know there's no way anybody could tell me for certain it would be fine or not I'm just getting paranoid, hence the bar clamps.

Iv been doing a lot of searching and its all over the place. Some say its fine some say its going to immediately explode.

To buy a temporary tank be it a stock tank or smaller glass would be just as expensive as buying a new used tank as I'm on a sump. I'd need filtration and everything.
 

Oughtsix

Redtail Catfish
MFK Member
Apr 9, 2011
1,600
553
150
Redmond, OR
First I don't like how you have it clamped. If you want to clamp it for safety put a wood block right over where the seam is separating and clamp right on top of the block / seam. I would recommend NOT putting the clamping pressure a couple inches in from the side like you have it. This can actually pull the outside seam apart causing more damage. The bar clamps you are using are not able to apply a lot of pressure. A pipe clamp will provider better support of the seam than those lite weight bar clamps.

I would use Weldon to weld that seam back together.
1) Drain the tank.
2) Stand it up on end.
3) Put the clamp where you have it positioned now. When you tighten the clamp you will actually open that bad seam a tiny amount.
4) Put some masking tape on each side of the seam to protect the rest of the tank from weldon.
5) Apply the Weldon to the bad seam.
6) When you have the bad part of the seam filled with Weldon wait about 5 minutes for the Weldon to soften the acrylic.
7) After 5 minutes remove the clamp which will likely push a bit of the Weldon out of the crack which is why you are protecting the tank with masking tape.
8) Reposition the clamp directly over the seam and apply LITE! clamping pressure. You don't want to clamp the seam so tight that you push all the weldon out of the seam. Use a wood block to spread the clamping force out over a large portion of the seam. You don't want a single point clamping force... you want the clamping force spread out over several inches of the seam.
9) Work on one seam at a time. Let it cure overnight before moving on to the next seam.
10) For the smaller bubbles in the seam you might have a hard time getting weldon into the bubble. Clamp the seam right over the bubble. Apply the weldon. Unclamp the seam which should suck the weldon into the bubble.

With a good re-weld job using Weldon I would trust the tank.

DO NOT USE SILICONE!!!!! Silicone will do nothing to help an acrylic tank. Silicone does not bond to acrylic well enough to provide any strength to the tank.
 
Last edited:

6lkl6l24

Feeder Fish
Jan 27, 2020
3
0
1
34
First I don't like how you have it clamped. If you want to clamp it for safety put a wood block right over where the seam is separating and clamp right on top of the block / seam. I would recommend NOT putting the clamping pressure a couple inches in from the side like you have it. This can actually pull the outside seam apart causing more damage. The bar clamps you are using are not able to apply a lot of pressure. A pipe clamp will provider better support of the seam than those lite weight bar clamps.

I would use Weldon to weld that seam back together.
1) Drain the tank.
2) Stand it up on end.
3) Put the clamp where you have it positioned now. When you tighten the clamp you will actually open that bad seam a tiny amount.
4) Put some masking tape on each side of the seam to protect the rest of the tank from weldon.
5) Apply the Weldon to the bad seam.
6) When you have the bad part of the seam filled with Weldon wait about 5 minutes for the Weldon to soften the acrylic.
7) After 5 minutes remove the clamp which will likely push a bit of the Weldon out of the crack which is why you are protecting the tank with masking tape.
8) Reposition the clamp directly over the seam and apply LITE! clamping pressure. You don't want to clamp the seam so tight that you push all the weldon out of the seam. Use a wood block to spread the clamping force out over a large portion of the seam. You don't want a single point clamping force... you want the clamping force spread out over several inches of the seam.
9) Work on one seam at a time. Let it cure overnight before moving on to the next seam.
10) For the smaller bubbles in the seam you might have a hard time getting weldon into the bubble. Clamp the seam right over the bubble. Apply the weldon. Unclamp the seam which should suck the weldon into the bubble.

With a good re-weld job using Weldon I would trust the tank.

DO NOT USE SILICONE!!!!! Silicone will do nothing to help an acrylic tank. Silicone does not bond to acrylic well enough to provide any strength to the tank.
Would I be doing that on the inside or the outside of the tank?
 

Oughtsix

Redtail Catfish
MFK Member
Apr 9, 2011
1,600
553
150
Redmond, OR
Would I be doing that on the inside or the outside of the tank?
Since the gaps are open to the outside of the tank you will be applying the weldon to the outside of the tank. I don't think I have ever seen gaps that open to the inside of the tank... but if they did you would adjust accordingly.
 

Oughtsix

Redtail Catfish
MFK Member
Apr 9, 2011
1,600
553
150
Redmond, OR
You will want to use Weldon #4 which is watery thin. It will wick into the gaps in the seams. The weldon will soften the acrylic then the softened acrylic will bond together making a permanent weld. Once you re-weld the seams I would expect the tank should be good for another 10 years.
 

Hari Haran

Jack Dempsey
MFK Member
May 30, 2018
72
38
36
You can use #4 betwen the seams and pour #40 on the inside, try looking into #40 tip and pour method.
 
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