# Cracked Viv repair



## Pumilo (Sep 4, 2010)

This is a thread detailing how to repair a cracked viv. I have 20 plus years working with glass professionally. 
I was recently given several brand new Euro style vivs with sliding front doors. They were given to me because they had cracked bottoms. They are otherwise in perfect, brand new condition so were well worth repairing. The first 4 will fill up a rack for me as these are very nice sized vivs. They measure 22.5" x 17" x 24" tall pushing almost 40 gallons each. Perfect 4 pack for a bakers rack. The final one will be my ultimate viv. It is a 70ish gallon corner display viv measuring 2 ft x 2 ft x 3 feet tall! I just got a group of 6 Southern Variabilis that should feel quite at home when I am done.
Let's start with a photo of the cracked bottom. I have turned the viv over for easy acess.


----------



## Pumilo (Sep 4, 2010)

As you can see, this is a frame-less viv. If yours has a frame, you will have to slice it off first. I would do this with a very thin, flexible, putty knife. I use a flexible putty knife like this to separate windows from the frames. If you use a tin snips to round the end of the knife, it will slide through much easier because the corners won't catch. Pic shows how the tool starts out and how it looks after cutting the corners.
You will have to run the putty knife several times all around the trim. Once it is removed, the rest of the job will go just like mine.


----------



## Pumilo (Sep 4, 2010)

I tried the guitar string method I've read about but the bottoms were much too tight. I got it to slide in about an inch before it began pinching the string and broke it. I ended up cutting them away with razor blades. You are going to want PLENTY of razor blades for this job. 
The first step will be to reach inside and cut through the "filet" or bead of silicone from the inside. I chose to leave the viv upside down and reach on through the front doors. On a more conventional tank you will flip it right side up first.
Run the blade all the way around the bottom. It may take a couple passes but cut until you feel the blade hitting the glass.


----------



## Pumilo (Sep 4, 2010)

After this is where it starts to get a little more difficult. You are going to try to slide your blade in between the cracked bottom and the bottom edge of the glass. In some spots, it may cut in fairly easily. Where it does, just keep running that blade along the edge, cutting it away. If you are really lucky, you can just cut the whole bottom away that way.


----------



## Pumilo (Sep 4, 2010)

I wasn't so lucky. As I said, these vivs were glued very tightly. I used several tricks to keep the blade cutting. When it got too tight, I slipped a second blade in behind the first one. This helped lift the glass a little bit, like a wedge, relieving some of the pressure on the first blade. 
Remember to keep replacing your blade as it dulls and chips quickly during all this.


----------



## Pumilo (Sep 4, 2010)

Eventually, I hit spots so tight that would not work either. I found that heating the glass with a hair dryer helped to make the silicone rubber just a little more flexible. Make sure you are only heating the cracked bottom pane.


----------



## Pumilo (Sep 4, 2010)

Still, I had spots where the blade would go no further. At this point, I held the blade with one hand and gently tapped the blade forward with a small hammer. You have to be careful not to hit the edge of the glass and also be careful not to let the "rib" of the razor blade hit the edge. You want just the skinniest portion of the blade slicing through.
Usually, after forcing the blade through for a half inch or an inch, I could continue slicing by hand.


----------



## Pumilo (Sep 4, 2010)

In some of the tightest areas, I did get some chipping, but only of the already damaged piece.


----------



## Pumilo (Sep 4, 2010)

Once you get around three sides, the last one is easy. You can begin to lift the pane away, like this.


----------



## Pumilo (Sep 4, 2010)

Then I used this simple, homemade tool. It's a razor blade, duct taped to a stick.


----------



## Pumilo (Sep 4, 2010)

With the bottom lifted, slip the corner of the blade into the last bead of silicone and "rock it" straight in, cutting through the bead.


----------



## Pumilo (Sep 4, 2010)

Repeat this step, till you've worked your way all along the last edge. (This is all done from the inside as you are lifting the pane, thus opening the gap on the inside edge, but making it even tighter on the outside edge.)
Once you've worked your way all the way down, you'll feel it just lifting away and with one simple slice, the bottom is completely removed.


----------



## Pumilo (Sep 4, 2010)

Fresh silicone does not stick well to old silicone so you must scrape off all you can. I chose not to use silicone removers as they could compromise the edges, and I don't like using mystery chemicals on something my frogs will be exposed to. Instead, I used my Random Orbital Sander with 80 grit sandpaper. It really made short work of EVERY LAST BIT of silicone from the bottom edge. Here, you can see some pictures of what it looks like when you begin sanding. Once you start sanding, it becomes very obvious where there is still silicone stuck. These pictures show areas that are NOT good enough yet.


----------



## Pumilo (Sep 4, 2010)

Here you can see we are very close to done.


----------



## Pumilo (Sep 4, 2010)

And here we are with every trace removed.


----------



## Pumilo (Sep 4, 2010)

Wipe it down with a damp rag, use several blades to remove traces of silicone still on the faces of the glass. One last quick wipe-down with some rubbing alcohol. 
Here you can see how I like to "notch" my silicone tube. This notch helps me to guide the bead exactly where I want it.
I use GE silicone 1. I don't use GE 2 because of the organotins in it. http://www.dendroboard.com/forum/parts-construction/35720-bio-seal.html


----------



## Pumilo (Sep 4, 2010)

Once your bead is complete you gently lower your new pane onto the inverted viv. This is easiest with two people. Grab some masking tape and tape it in place.
After it is taped in place, you'll want to reach inside and smooth out your bead. There are tools for this but I hate them. I just use my fingers and plenty of paper towels.
Give it 24 to 48 hours before removing the tape. 
I'd show you the completed vivs, but they are drying!


----------



## Rhesus Feist (Jan 20, 2011)

Great write up.

One question I had because it is a bit hard to tell from just your picture, but are you putting the bead of silicone on the edges of the existing glass of the tank, or on the new piece of glass? I'm guessing your putting it on the edges of the tank glass, at least I think thats what I'm seeing in the picture, you use the little notch to stay on the edge of the glass?

Another question, any recommendations on minimum thickness of glass to use? I know that the size of the tank and how much weight you'll have in the tank (filled with water or not) would change things, but got any general rules to follow?

Thanks for putting this together, I've got a 30 gal long laying around with a broken end pane. Maybe this will motivate me to finally do something with it.


----------



## Shohin (Sep 21, 2011)

Good job with the post and "how-to" Pumilio. Thanks.

Great looking corner viv, too. What a score for you!

-Troy


----------



## Pumilo (Sep 4, 2010)

Shohin said:


> Good job with the post and "how-to" Pumilio. Thanks.
> 
> Great looking corner viv, too. What a score for you!
> 
> -Troy


Thanks Troy, wait till you see it completed! I've been saving up the choicest pieces of ghost wood and cork bark with a bunch more on the way.



Rhesus Feist said:


> Great write up.
> 
> One question I had because it is a bit hard to tell from just your picture, but are you putting the bead of silicone on the edges of the existing glass of the tank, or on the new piece of glass? I'm guessing your putting it on the edges of the tank glass, at least I think thats what I'm seeing in the picture, you use the little notch to stay on the edge of the glass?


You've got it exactly. Silicone on the existing edges, using the notch as a guide. The new glass goes on clean (no silicone).



Rhesus Feist said:


> Another question, any recommendations on minimum thickness of glass to use? I know that the size of the tank and how much weight you'll have in the tank (filled with water or not) would change things, but got any general rules to follow?


That's too easy. Copy the size the manufacturer used. Mine were built with 1/4" so that's what I went with. 
When I build from scratch, I use 1/8" for my vivs up to 25 gallons. This is rather thin but it's free scrap glass so I use it. With only the inch or so of water under the false bottom, they work fine as long as I'm careful. I step up to 3/16 for my 24" x 24" x 24" 50 gallon size slope fronts. If I were purchasing glass instead of the free scrap I get, I would step up to 3/16" for my 25s and 1/4 for my 50s.



Rhesus Feist said:


> Thanks for putting this together, I've got a 30 gal long laying around with a broken end pane. Maybe this will motivate me to finally do something with it.


Good luck with it!


----------



## night30 (Oct 21, 2009)

doug,
thanks for the directions. what do you use to remove any remaining silicone from the tank? and also to clean the panes before reassembly?

thanks,

dave


----------



## Tuckinrim8 (Jul 26, 2007)

Hey Doug,

Thank you for detailing this! I know there are many of us who have wanted to attempt fixing a viv and just didn't know where to start. Keep up the good work! I cant wait to see how these turn out! 
ps. nice signature! 

Chris


----------



## Pumilo (Sep 4, 2010)

Tuckinrim8 said:


> Hey Doug,
> 
> Thank you for detailing this! I know there are many of us who have wanted to attempt fixing a viv and just didn't know where to start. Keep up the good work! I cant wait to see how these turn out!
> ps. nice signature!
> ...


I was overdue for an update, thanks!



night30 said:


> doug,
> thanks for the directions. what do you use to remove any remaining silicone from the tank? and also to clean the panes before reassembly?
> 
> thanks,
> ...


Hey Dave, page 2 details how I sand the edge down with a random orbital sander to remove every trace of silicone from the cut edges. I use a handful of razor blades to remove silicon from the faces of the glass near the edge. I wipe the panes down first with a damp rag to remove sanding dust, followed by wiping down with rubbing alcohol.


----------



## intelsuit (Jul 31, 2011)

Pumilo said:


> I was overdue for an update, thanks!
> 
> 
> 
> Hey Dave, page 2 details how I sand the edge down with a random orbital sander to remove every trace of silicone from the cut edges. I use a handful of razor blades to remove silicon from the faces of the glass near the edge. I wipe the panes down first with a damp rag to remove sanding dust, followed by wiping down with rubbing alcohol.


This is awesome! You almost make it look easy. Almost. I hope I never have to repair a crack but if I do I would approach it with more confidence thanks to this post. Heck, I'm almost thinking of posting an advertisement to see if someone will give me one to try it out. Thanks!


----------



## Pumilo (Sep 4, 2010)

intelsuit said:


> This is awesome! You almost make it look easy. Almost. I hope I never have to repair a crack but if I do I would approach it with more confidence thanks to this post. Heck, I'm almost thinking of posting an advertisement to see if someone will give me one to try it out. Thanks!


Watch Craigslist. They go up all the time. Ask your local fish shops.


----------



## Ed (Sep 19, 2004)

Doug if you were closer I would trade you use of my huge pressure cooker if you repaired a tank for me... 

Ed


----------



## Pumilo (Sep 4, 2010)

Thanks Ed, but flying out to Jersey would that one expensive pressure cooker run!


----------



## Noort (Feb 10, 2012)

Verry nice job 

I have to remove a pane myself in the very near future and am NOT looking forward to it.

Your tool is a very good idea!! I'll try it!

Just one question: the cracked panes are all 'bottoms' right?
Why didn't you just silicone another layer of glass on top of the cracked ones?

(It works fine with fishtanks, afaik, as long as you allow some of the silicone to fill the crack as well. Recently I read the story of a man who repairs cracked bottoms with 2 component-resin: he uses a very thin mix and let it fill the crack as well as making a little weld -> by using the same dam-methode as you did drilling holes -> watertight and animal friendly. The other side of the glas is taped off course, otherwise the mixture would run straight through. )


----------



## SNAKEMANVET (Dec 14, 2011)

Nice how to,I had to do this to my 240.It took me about 2 weeks to remove the bottom glass.Instead of a orbitial sander,I used a drill with a wire wheel to remove the silicone residue.It is fun trying to remove 1/2'' glass with razor blades


----------



## Pumilo (Sep 4, 2010)

Noort said:


> Just one question: the cracked panes are all 'bottoms' right?
> Why didn't you just silicone another layer of glass on top of the cracked ones?


Working with glass is my life. That's a bit like asking a chef why he didn't just serve Hot Pockets, or asking a carpenter why he didn't just use a cinder block stand for his fish tank. 
If I can do the job right for a beautiful 75 gallon display viv, why wouldn't I?


----------



## jchollenb (Mar 30, 2010)

Since ur a glass worker, any suggestions as far as removing scratches from glass?


----------



## Pumilo (Sep 4, 2010)

jchollenb said:


> Since ur a glass worker, any suggestions as far as removing scratches from glass?


Sorry, no. One of my suppliers does sell a buffing tool for removing scratches in thicker, industrial glass, but it's something like a grand for the tool and kit.


----------



## jchollenb (Mar 30, 2010)

ouch! Its glass from a tank i picked up cheap and tore apart long ago... which was silly on my part, it was a 125 gal, 1/2" thick glass. Now I dont know what to do with all the glass and im hesitant about putting it back together frameless.


----------



## Pumilo (Sep 4, 2010)

jchollenb said:


> ouch! Its glass from a tank i picked up cheap and tore apart long ago... which was silly on my part, it was a 125 gal, 1/2" thick glass. Now I dont know what to do with all the glass and im hesitant about putting it back together frameless.


Personally, I would have no qualms about putting it together frameless with glass that thick. This is, of course, assuming it will be a viv and NOT a fully filled fish tank. Also, you will want to make sure you have a good, heavy duty, and very flat plywood support for it.


----------



## jchollenb (Mar 30, 2010)

Im not so worried about my ability to build a solid stand to support it. Just worried that something will go wrong because of my inexperience puttin a tank like that together. I'll prolly give it a try when the weather warms up, worst thing that will happen is it will fall apart and make a massive mess to clean up.


----------



## Noort (Feb 10, 2012)

Pumilo said:


> Working with glass is my life. That's a bit like asking a chef why he didn't just serve Hot Pockets, or asking a carpenter why he didn't just use a cinder block stand for his fish tank.
> If I can do the job right for a beautiful 75 gallon display viv, why wouldn't I?


LOL You are absolutely right of course.
I hope I didn't offend you with my post (If I did it was unintentionally!!)
I wouldn't dream of telling a professional how to do his/her job. 
(Other than my own of course )

It just popped into my head, because I realise what a huge amount of work it is/ has been and nobody ever looks at the bottom of a vivarium after the false bottom/ ground couver etc. are in place.

It (the question) was more of a practical than aesthetical nature.
And -since I am just a beginner- just wondering if it made any difference in the overall sturdiness ( if a person would just stick another sheat of glas on top of the cracked one. -> the 'easy way out' for the non-professional so to speak. I have more experience in fixing bicycletires than I do fixing tanks, so maybe my thinking is warped)

You did a marvelous job on that tank, there is no denying that and I respect your professional pride in what you do.

(btw, I'm from Europe and haven't got a clue what Hot Pockets are/ must be some kind of fast-food?)


----------



## Pumilo (Sep 4, 2010)

Noort said:


> LOL You are absolutely right of course.
> I hope I didn't offend you with my post (If I did it was unintentionally!!)
> I wouldn't dream of telling a professional how to do his/her job.
> (Other than my own of course )
> ...


It's ok, no offense taken. They method you mentioned would be fine for someone with less experience.
As far as Hot Pockets go, lucky you. They are low quality meat and processed cheese wrapped in what must be a cardboard pastry wrap. You're not missing a thing!


----------



## Pumilo (Sep 4, 2010)

One important thing I've neglected. WEAR GLOVES! Get some good, heavy duty, leather, work gloves. I know I didn't in the pics, but I have a bit of experience working with glass.


----------



## jacobi (Dec 15, 2010)

Pumilo said:


> Instead, I used my Random Orbital Sander with 80 grit sandpaper. It really made short work of EVERY LAST BIT of silicone from the bottom edge. Here, you can see some pictures of what it looks like when you begin sanding. Once you start sanding, it becomes very obvious where there is still silicone stuck.


Doug, I am attempting something similar, I already removed the broken bottom pane, but I don't have access to an orbital sander. Do you think sanding manually will work?


----------



## Pumilo (Sep 4, 2010)

jacobi said:


> Doug, I am attempting something similar, I already removed the broken bottom pane, but I don't have access to an orbital sander. Do you think sanding manually will work?


Of course, it'll just take a little time and elbow grease. I think I would make a padded block for that. In it's simplest form, cut a 6" piece of 2 x 4. Cut a 6" wide strip of towel and wrap it around the block. Wrap the sandpaper around that. 
Whatever you decide to try, protect your hands. If you just held sandpaper with your bare hand, you could get a nasty cut when the glass wears or cuts through the sandpaper.
Good Luck!


----------



## jacobi (Dec 15, 2010)

Pumilo said:


> Personally, I would have no qualms about putting it together frameless with glass that thick. This is, of course, assuming it will be a viv and NOT a fully filled fish tank. Also, you will want to make sure you have a good, heavy duty, and very flat plywood support for it.


Another question, hope you don't mind! For smaller tanks do you think it is necessary to have the tank completely supported if one removes the frame?


----------



## Pumilo (Sep 4, 2010)

jacobi said:


> Another question, hope you don't mind! For smaller tanks do you think it is necessary to have the tank completely supported if one removes the frame?


Absolutely.


----------



## DendroRachel (Jun 21, 2011)

nice thread! thanks for all the pics, tips, explanations! excellent!


----------



## Pumilo (Sep 4, 2010)

You're welcome. By the way, just a report back on this. All 5 of these vivs that I replaced the bottom glass on, have been in use for over a year now. There are NO leaks whatsoever.


----------

