# Bubble in seam! tank build



## discusdan (16 Apr 2014)

Hey all, 

I'm in the process of building a rimless tank using silicone injection method.
see this thread for details. http://www.ukaps.org/forum/threads/diy-rimless-tanks-whos-built-one.32279/
(thought more people would see this thread in this sub forum)

Every thing was going well until I saw this






I got a bubble in the seam.

Its only this one bubble, the rest of the seams came out well.





The bubble occurred in the initial blob that holds the tank together, You can see one of the other blobs in another seem that is ok.





I did some research and found bubbles in aquarium seams is quite common with some people saying that they look unsightly but pose no structural issues and others saying they are trouble waiting to happen.

What do people think? does any one have any bubbles in their aquarium seams and if so have you had any issues?

I might as well water test the tank as its ready for it but do you think this one bubble will be an issue?

I'll be gutted if I have to split the tank down and start again


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## kirk (16 Apr 2014)

firstly, I'm no tank builder. I have worked with silicone onvmany things and it's strong stuff but so is water pressure.I'd say the amount of silicone holding above and below the bubble plus the tidy unbroken bead down the inside it's not a problem.  The cosmetics ( bubble) would bother me though.  if you think you will be sat worring all the time, thinking it may blow, redo that pane. or is it not that simple on a rimless build.? As you say injection, couldn't you inject into the bubble and fill it so it less noticeable?


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## discusdan (16 Apr 2014)

Cheers for the reply Kirk.

I did initially think about getting a syringe and injecting silicone through a needle into the bubble but I think silicone is too thick to be pushed through a needle?

I'm not too fussed on how it looks, I can put that side to the wall so it will never be seen, I was more concerned about it holding out once filled with water.

I guess I could just redo that one pane but not sure if it would just be easier to take apart the whole thing and start over


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## Alastair (16 Apr 2014)

I personally would redo the whole tank. Its those seams that actually keep the panels held together when the pressure of the water is pushing against it. Not the beads down the inside corners. That looks like the inner part of the bubble hasnt adhered and depending on tank size once full the pressure on the seam with the bubble in will cause the bubble to increase.


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## Tim Harrison (16 Apr 2014)

I agree with Alastair...I think it needs redoing...


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## Edvet (17 Apr 2014)

If you wan't to redo that side you could try to cut that one seam with a wire (google for removing car windows).


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## discusdan (17 Apr 2014)

cheers for the replies chaps, think im going to tear it down and redo the whole tank. Better safe than sorry and nows the best time to do it while its all clean and tidy.


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## discusdan (17 Apr 2014)

So it was easier to pull the tank apart than I was expecting. Still have to get all the silicone residue off and clean the glass but that can wait for tomorrow.

I used a stanley blade in a scraper handle to remove the water seal on the inside of the tank. I just pushed it in from both sides and the silicone came out as one long strip.

I then got some 25lbs fishing line and tied it between two sticks and used it like a kind of saw to cut down the seam (like the wire trick) and it worked a treat.

But now for the worrying part, I'm using 10mm glass and the silicone in the middle of the seams was totally uncured.

It was fully cured towards the edges where the air could get to it but i'd say the middle 3-4mm was all uncured.

I only siliconed the tank together two days ago so do you think it just needed more time for the silicone in the middle to cure?

Or do you think the silicone at the edges skinned over first and stopped air getting into the middle creating a pocket of uncured silicone, and was this due to the injection method?

I'm in two minds now whether to do it the normal way of laying beads down, but I can imagine you could get the same effect. As you lower the pane of glass down onto the bead of silicone the edges will cure first and still leave a pocket of uncured silicone in the middle?

The injection method was easy to do and i'd do it again as long as there isn't a curing problem?


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## Humbert (17 Apr 2014)

Hi. I'm not an expert on tank building, but the company that built my aquarium (10 mm glass thickness) said that normally the curing time for silicone is 2-3 weeks.
They advised against filling with water before that time.
So I would say that after  2 days it is perfectly normal for the inside silicone to be uncured.

simplest thing to do: when you build the aquarium, glue together 2 pieces of glass of the same thickness with the same amount of silicone. 
you can then test when the silicone is fully cured by verifying the bond on these 2 pieces of glass.


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## discusdan (17 Apr 2014)

I've heard that silicone can take a few weeks to fully cure, strangely it doesn't mention curing times on the tube.

Thats an excellent idea on sticking two bits of glass together at the same time, unfortunately I dont have any spare glass to use


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## Humbert (17 Apr 2014)

sorry, it does not need to be glass of the same thickness, I think any 2 pieces of glass will do. what's important is that the thickness of the silicone is the same as on the aquarium.


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## discusdan (17 Apr 2014)

ah i see what your saying now, its worth a go.


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## discusdan (18 Apr 2014)

so it seems taking a tank apart can be done fairly quickly, removing all the silicone not so much!

Has taken most of the day to clean all the silicone residue from the glass, in the end after a google search I resorted to isopropyl alcohol and 0000 wire wool and plenty of elbow grease. Got it all shiny in the end but boy did it take some work.

Got the tank jigged up and went for the injection method again as its so clean and easy but this time I siliconed the whole seam and just left the small part where the cable tie is to finish off. I'm also going to leave it in cramp for a good week as well to give the silicone more time to cure. I think I removed the cramps to early the first time.

I also found two small bits of perspex which I've siliconed in the same way so I can see if its gone off after a week.

I'll let you know how I get on, wish me luck


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## Alastair (18 Apr 2014)

1 day for each mil thickness of glass for full silicone cure and even then add a few extra days on


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## Rockfella (16 May 2021)

discusdan said:


> so it seems taking a tank apart can be done fairly quickly, removing all the silicone not so much!
> 
> Has taken most of the day to clean all the silicone residue from the glass, in the end after a google search I resorted to isopropyl alcohol and 0000 wire wool and plenty of elbow grease. Got it all shiny in the end but boy did it take some work.
> 
> ...


Nice. I know the thread is is 7 years old but any info on this subject seems timeless. I am in almost the same situation. I tried the injection method but with 1.5 mm - 2mm thick gap between panes and to top it all I bought an aquarium grade German silicon which was really thick. It barely come out of the pinched nozzle. The gun broke mid way! This time I will keep 3 mm gap and go for easy to use to use silicon. I tried mineral spirit to get rid of cured silicon but it was too much work + mineral oil on the glass made me nervous and it can make the seams weak and cleaning it another task so I will get almost all panes again by 10 mm (my glass thickness) and retry! Hope your tank is holding well.
Regards,
Vivek.


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## zozo (16 May 2021)

These gaps only happen if the glass edge wasn't properly cleaned and still greasy... Touching it with a finger could be enough to leave a greasy residue. We are particularly greasy even if you wash your hands 10 x a day.

The one thing silicon hates is greasy surfaces... Then you can try to put even more silicone into the gap, the fat will prevent it from sticking to the glass. That's all to it... Thus the tank builder simply did an irreversible sloppy cleaning job before assamblimg it.

If the bubble only is in the glass contact area but the silicon seam in the corner is intact. Then you could still be good to go. I've seen and even used tanks with these issues for years without problems. If what the pictures in this thread show were my tank I think I wouldn't worry that much. But I obviously can not give you any guarantee... A picture might not show it all...

Best practise, don't torture yourself and redo it.... Even tho redoing ain't always this easy either. Because new silicone hates old silicone... etc.
Forget or overlook a bad cleaned spot and it will show again as is now. The aquarium building is a one-way ticket to the blues.


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## Rockfella (22 May 2021)

zozo said:


> These gaps only happen if the glass edge wasn't properly cleaned and still greasy... Touching it with a finger could be enough to leave a greasy residue. We are particularly greasy even if you wash your hands 10 x a day.
> 
> The one thing silicon hates is greasy surfaces... Then you can try to put even more silicone into the gap, the fat will prevent it from sticking to the glass. That's all to it... Thus the tank builder simply did an irreversible sloppy cleaning job before assamblimg it.
> 
> ...


Just adds up to use acetone minutes before applying silicon and never touch the glass which the silicon will stick on with bare hands.


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## zozo (22 May 2021)

Yup.  And if you ever build one yourself then inspect the cut-glass edges. It's said glass is cut but it actually isn't it's only scratched for a fraction of an mm and the rest will snap off, thus it's a break or a fracture. Then if you look very close to the surface of this broken edge it kinda looks like a bumpy road with nooks and crannies and potholes. Then if you run a cloth over this edge to clean it the acetone-dampened cloth will jump over the bumps and potholes in the road like a speeding rally car missing the declined spots behind the bump.

Then after assembling the glass the silicon will retract and detach from these missed surfaces while it is skinning resulting in an air bubble. The skinning time is between 8 and 12 minutes and when it shows it's always too late. Because the entire tank needs to be completely done within the specified skinning time. Thus it's a hasty but Mise en Place job building tanks...

With 4 and 6mm glass thickness it is rather hard to see that the cut edge is actually very irregular, 8mm glass and above it becomes more obvious. You can't clean it often enough and wipe in all directions from down to up, and up and down. left and right and right and left. And get a feel for the edge you are cleaning. Double-check and clean again. For the cleaning part rather use a textile glove from a thin soft fabric. And apply sealant with a latex glove.


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## Rockfella (22 May 2021)

zozo said:


> Yup.  And if you ever build one yourself then inspect the cut-glass edges. It's said glass is cut but it actually isn't it's only cut for a fraction of an mm and the rest will snap off, thus it's a break. Then if you look very close to the surface of this broken edge it kinda looks like a bumpy road with nooks and crannies and potholes. Then if you run a cloth over this edge to clean it the acetone-dampened cloth will jump over the bumps like a speeding rally car missing the declined spots behind the bump.
> 
> Then after assembling the glass the silicon will retract and detach from these missed surfaces while it is skinning resulting in an air bubble.
> 
> With 4 and 6mm glass thickness it is rather hard to see that the cut edge is actually very irregular, 8mm glass and above it becomes more obvious. You can't clean it often enough and wipe in all directions from down to up, and up and down. left and right and right and left. And get a feel for the edge you are cleaning. Double-check and clean again. For the cleaning part rather use a textile glove from a thin soft fabric. And apply sealant with a latex glove.


I got the glass cut with a pro .. they used machine. One part was not cut properly I took that pane back to them and got it done again. What you said is IMHO very important. I see too many people (tube vids) touching the glass before applying silicon. The vid looks fine in the end but then when the tanks leak they don't post it after years of usage.


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## zozo (22 May 2021)

Rockfella said:


> The vid looks fine in the end but then when the tanks leak they don't post it after years of usage.



That is with about 99% of the 5 minutes of fame DIY videos, only showing the short-term successes. always failing to update on the long-term failures, flaws, and errors.

Like these DIY siphon overflow tutorials, all presented as a Eureka invention.



And it's the worst functioning overflow you could ever build, a 95% chance you'll trash it within a few months of use and skip to something else. There are 1001 videos on how to build them and none with an update on how horribly they are in the long run and why and how to trash them again.


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## Rockfella (22 May 2021)

zozo said:


> That is with about 99% of the 5 minutes of fame DIY videos, only showing the short-term successes. always failing to update on the long-term failures, flaws, and errors.
> 
> Like these DIY siphon overflow tutorials, all presented as a Eureka invention.
> 
> ...


Lol  I will just go with an overkill top filter. Ton of ADA Bio Rio and mechanical media.


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