DIY Tank Re-Seal Full Instructions

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Thaiboxer

Aquarium Advice FINatic
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How to Completely Reseal Your Glass Tank

(Kudos to gooyferret, I borrowed a lot of information from his posting on how to fix a leaky tank.)

Before you start – these directions only work on glass tanks! If your tank is acrylic, stop reading now!

What you will need:
1. Bottle or tube of 100% silicone, your able to pick these up either at your local HD, LFS, or your nearest Home Improvement Center. Make sure your silicone doesn’t have any antifungicides or other additives – they can kill your fish!
2. Razor Blades (caution very sharp). I also recommend getting one of those scrapers that makes the razor blades easier to hold and wield.
3. Bottle of Rubbing Alchohol and cotton swabs. (I used paper towels, will explain later)
4. Mineral Spirits (soap doesn’t work very well to clean your hands later!)

What to do:
- If the tank isn’t already empty and dry, empty it and let it dry! That said, use your razor blade to remove all of the old silicone from the bottom and corners. Try to get as much as you can out from in between the pieces of glass as well. At varying points, use a shop-vac to suck up the pieces of silicone you’ve carved away from the glass.

- When you think you’ve got it all and the tank is clean, use a cotton swab or paper towel with rubbing alcohol to clean the joints. I used a paper towel because you can “feel” the sticky spots on the glass where a little bit of silicone remains. Go around the tank 3-4 times cleaning off any remaining silicone with alcohol and a razor blade, letting it dry after each cleaning. When you are satisfied that all of the old silicone is gone, let the tank dry completely and go on to the next step.

- Now you are ready to apply your new coat of silicone. Before you start, get a small glass (shot glasses work great) about halfway full of rubbing alcohol. Silicone dries quickly so you’ll need to be very efficient, especially if you’re working on a large tank. Set your rubbing alcohol in the tank (I worked with the tank standing up), and cut the nozzle on your silicone tube. It helps to have extra paper towels handy at this point to wipe extra silicone off your fingers in between edges.

- Squeeze your silicone bead along an entire edge of the tank, and don’t be stingy! When you’ve finished applying the silicone to an edge, dip your finger in the rubbing alcohol and smooth the entire edge making sure there are no air bubbles. Wipe your hands (mostly) clean and move on to the next edge, covering them all in the same manner.

- When you’re finished, you should have a nice even bead where all of the pieces of glass join. Use mineral spirits and paper towels to get all the silicone off your hands, then follow up with soap. Let the tank dry for at least 24 hours, then apply a second coat if you feel it is necessary.

- Once the tank is sealed and has cured for more than 48 hours, use a razor blade to clean up any spills on your glass. The extra silicone should peel off of flat surfaces fairly easily… you’re probably an expert by now!

Hopefully this covers everything! Good luck on your project!
 
Does anyone have anything to add on this one? I'd love to incorporate anything I missed to have these instructions as complete as possible. Thanks!
 
I would also like to make it a full fledged article once you deam this complete.

We are on the same page, when I made it a stickey I asked Thai to give it a once over and we could make it an article ;)
 
I'm going to add some notes, then finalize it.

Post-sealant:
- Leak check: Once the sealant has cured for ~48 hours, put about 2" of water in the tank. Do a walkaround (or just look carefully... mine's a big tank) and look for air bubbles in the silicone. I found one in mine, and followed Gooyferret's patching advice. I removed about 3" of silicone, and put down new. Also look carefully at each corner for air bubbles, as they will compromise the integrity of your silicone.

Tips for an easier job:
- Get a helper. They don't have to know anything about silicone or aquariums, they just need to be willing to squeeze the silicone tube for you. On larger tanks especially, you don't want to go back and forth between squeezing the tube and smoothing the silicone with your finger. (The tube gets really sticky!)

- Don't be stingy with the silicone! Especially on the bottom where nobody is going to see it anyways.

- Before you set your tank up in your living room, do a leak test in your laundry room, or outside... somewhere you don't mind getting wet. This probably won't happen, but if it does you'll be grateful. (It didn't happen to me, I'm just thinking ahead...)

- No matter how excited you are to get fish in there, let your tank dry completely before putting water in it! 48 hours means 48 hours!
 
After removing all of the silicone, you'd be left with 5 pieces of glass. In what order do you glue them together, and how do you hold them in place at 90 degree angles to one another while they're setting?

-J
 
Good question! My tank is held together by metal braces that surround the top and bottom, so I was never down to separate pieces of glass. I'm sure on mine that some silicone remained in the cracks as well, but I just pasted over it.

Aren't there braces surrounding your tank, holding it together? If there are, metal or plastic, I would leave those in place and work around them. Hope this helps.
 
Hello Folks,

Here's somethings I did when re-sealing a 40 Gal Hex. I used Acetone vs Alcohol (That's what the folks at my Local HD store advised). It worked ok, I never tried Alcohol, so not sure if there is any differences.
For the prep of the tank, after stripping the old silicone, I used masking tape to mark where I wanted the new silicone, also it helped insure the new silicone sides were straight. Basically imagine where the silicone should be, then place the masking tape on the sides of, where you want your new silicone, hope that makes sense(at work, in a press for time). I left about a 1/2 inch for the new silicone, depending on the size of the tank.
Once I got the masking tape in, I Siliconed away. After applying the Silicone, I used a latex or vinyl glove, to spread the silicone bead out, working out the bubbles. (I just used a paper towel to clean off my finger tips of the glove once is collects too much silicone to work with.) Before it the silicone starts to cure, I removed all the masking tape and left it to dry.
 
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