# DIY - Tank Re-Sealing (My way)



## bscman (Mar 23, 2007)

There seem to have been a rash of "My tank leaked" or "Should I reseal this tank before I use it" type threads recently, so I thought I'd jump in and give a quick little "How-To" to help build confidence on your next re-sealing adventure!

First things first, Items you'll need:

Small package of SINGLE EDGED razor blades
Tube of silicone (GE Type I window/door, All-Glass Aquarium Sealant, etc.)
And an applicator "gun" for the silicone.
Paper towels

(If you can't find the listed silicones, anything that says 100% silicone will work. Make sure it does NOT say "mildew and mold resistant" as those have chemicals in them that will leach into water and are harmful to fish. I believe the GE Type I is also called window and door)

The silicone and a cheap applicator gun shouldn't cost more than $5-6 total, and the razor blades will depend on how many are in the box...you'll probably need at least 4....I buy them by the box of 100 but I use them a LOT for things like cleaning, tinting windows, opening boxes, etc. 
IIRC, a box of $100 is also about $6.

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## bscman (Mar 23, 2007)

Now your very first step!
Empty your tank of all water and decorations. If the tank is currently a home to fish, you'll need to find them a new home that will suffice for about three days. A spare tank is a great idea (cheap at yard sales, thrift shops, etc)
It that is not an option, new 10g tanks are inexpensive ($10) or you can use a large rubbermaid container or similar. Remember, you'll still need at LEAST a heater in the temporary tank!

Once empty and cleaned, you can use the razor blades to remove ALL the old silicone from the insides...and I mean ALL of it! New silicone will not adhere to old stuff--there is no quick fix for a leak. You must reseal the ENTIRE tank to do it right!

I find it easiest to run the razor blade flat against the glass (a sharp, unbent blade won't scratch the glass) with the edge of the razor blade digging into the corner where two pieces of glass meet. The razor blade will dig in under the silicone separating it from the glass.
However, the corner of the blade will become dull with use...so don't be afraid to grab a new one. Be carefule, they are EXTREMELY sharp!

Repeat for the other side of glass (juxtaposed to the same corner). From there, the silicone will peel of quite easily. Once the mass of silicone is off, run the blade along the edge again, to make sure all the little tid bits come loose as well. This is critical. There will always be little chunks of silicone left behind--they must be removed as well, or the new stuff won't properly adhere to the glass. Run your finger along the edges of the glass to feel for remaining silicone.

Repeat for all four sides and the bottom.

You can buy a chemical that will eat away the silicone, but it's not worth it IMO...a razor works fine and it less messy! 
Usually those "just spray, and wipe away" miracles are mostly hype--and just make for a bigger cleanup job.
Once all the silicone is off (including every little tiny fleck), you'll need to completely clean the glass (no silicone residue, no oily fingerprints).

Choose your method here, anything will work--lets be realistic, it's easy to clean chemicals from glass, as glass isn't absorbant. Whatever you choose, make sure you clean it out THOROUGHLY so your fish don't get sick later on. 

My recommendation is a mild soap and a scotchbrite pad. You just REALLY have to make sure the tank is fully rinsed clean before you re-introduce fish...because left over soap residue can be harmful.

Silicone is extremely adhesive to glass...it is NOT adhesive at all to water or oils, and typically is much less tacky to old silicone. This is why a good cleaning is so imperative. If you don't clean the joints well, the new silicone won't adhere well and it may leak!

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## bscman (Mar 23, 2007)

Once everything is CLEAN and especially DRY, you're ready to silicone.
Cut the tip off the tube of silicone, and insert it into the applicator. Squeeze the handle until it starts to squirt silicone.

If you chose to use a squeeze tube type silicone, rather than a tube and applicator gun, this is fine...just be aware your fingers might get a little sore by the time you're done. The applicator guns will generally make it easier to get even coverage throughout the tank.

I like to start by siliconing the sides, then do the bottom. It's up to you how you want to do it. I usually lay the tank on it's side (carful, remember silicone holds it together, and you just removed most of it ;-) )

I start at the "top" of the tank, and work down towards the bottom--so I guess with the tank on it's side, that's start at the open end, and work to the other end!

You want to silicone like this:









This way, as you push the tip forward AND simultaneously squeeze the handle and squirt our the silicone, you are actually doing two things.

First, you are PUSHING the silicone into the corner -- so you make sure it has a good seal.
Secondly, you are smoothing out the silicone--as the tip travels over the top of the freshly layed silicone, it will form a nice smooth layer.

Start at the open end of the tank and push to the bottom as you lightly squeeze the handle. You don't need a lot, remember how it looked before you removed the old stuff? That's what your goal here is. 
Modulate pressure and speed until you get the right sized bead of silicone. Too much isn't a bad thing, just might look a little gobbed up by the time you're finished. Too little IS a bad thing. Err to MORE rather than less. 

You will want to got a little heavy on the top and especially the bottom corners. These tend to be where a lot of leaks start. If you paid attention before you removed the old stuff, you'd see there is a fair bit of silicone on all four bottom corners, as well as all four top corners near the rim of the tank.

Once you reach the bottom, stop!
Go on to the next corner...until all four sides are done.

Upright the tank, and finish with laying a bead around the entire bottom of the tank! Voila! You're done!

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## bscman (Mar 23, 2007)

IF you aren't happy with the way your bead looks, you can wet your finger and smooth it out. This is also the best time to remove any boo-boo's you made... (Like that big glob of silicone you accidently left in the middle of the front panel! :lol: )
Wipe clean with a paper towel. If you can't get it all, don't fret. Once the silicone is dry, you can use your razor blade to cleanly scrape off any mistakes.

If you make a big mistake, or end up with wayyy more silicone that you need, you can always scrape it off and start over. I usually just wait for it to dry, and repeat the entire process over. No point in continuing to seal the tank if you already made a big mistake -- but mistakes like this aren't common!

If you're a perfectionist, you can use masking/painters tape to can make nice clean lines. Simply take a little time before you start siliconing to tape off where you don't want the silicone. Then, once you're done siliconing the tanks, remove the tape while it is still wet...Voila, clean, straight, perfect lines!

One tube (10.5oz) of silicone should be enough to do at LEAST two 30g tanks, probably even three...so if you mess up, there's enough to start over later!

Allow the silicone to dry for at about 48 hours before filling it...three to four days wouldn't be a bad idea, but probably aren't required. I've never had any problems by only allowing 2-3 days to cure--most silicones are cured in ~48 hours. Read the silicone label for recommendations.

Now, fill the tank FULL of water and let it sit for at least a day to make sure it still holds water. Setting the tank on colored paper or paper towels will help show leaks, if there are any. 
Please, don't just fill it and throw your fish it...letting the tank stand with water not only ensures the tank doesn't leak (peace of mind) but also gives time for any soap residue, silicone ingredients, etc. to leach into the water. This shouldn't be a problem, but hey--better safe than sorry, right?

Lastly, I apologize for breaking my How-To into several posts. I wanted to make this as easy as possible to read...so I figured breaking each step into it's own post would help.
Don't hate me  

The next time I'm re-sealing a tank I'll try to add a few pics to this thread!


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## duke33 (Jun 9, 2007)

That, my friend is one fine teaching! Thank You for breaking it down like that. I have had to reseal tanks myself, You described it to a T.


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## davedudeman (Jun 25, 2007)

Cool. I am sure to use this as a guide once I pickup my used 46 gal bow front.
Doing this is just to reseal joints of the glass and isn't going to damage the strength of the tank will it?


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## bscman (Mar 23, 2007)

davedudeman said:


> Cool. I am sure to use this as a guide once I pickup my used 46 gal bow front.
> Doing this is just to reseal joints of the glass and isn't going to damage the strength of the tank will it?


The silicone, without a doubt, holds the edges of the glass together....as does the top and bottom rim.

With all the old silicone removed, you should be caution with handling the tank...but again, there is still adhesive between the points where the glass butts up against each other, and still has the top and bottom rims holding it together. Once re-sealed, you're good to go.


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