silicone in a 29 gallon tank (help!)

[Guppygirl]

I just bought a used 29 gallon tank. After getting it home I noticed that is doesn't have much silicone in the corners of the tank. It also has a few tiny chips to the glass edge. It seems solid. My other 29 gallon has about a 1/4 inch worth of silicone on each side of the corner seam. Is the corner silicone important or is it more the silicone between the glass? This worries me as I don't want a leak or blow out. Can I add a bead of silicone and spread it? Will new silicone go with old silicone even thou there is little old silicone. Any help would be wonderful. Thank you :bow: :bow: :bow:

[randy]

Adding some new silicone cant hurt, the more important part is the silicone between the glass. Check out the DIY section to see how to re-silicone the tank (can be quite messy with out practice)

[fleshgear]

new silicone apparently does not stick to old silicone that well. you can cut out the silicone in the corners with out going in between the glass. and then re apply the new silicone. this can get messy. and isn't as easy as it seems unless you have experience applying silicone.

the trick is not to apply to much silicone in the first place. or use the tape method i havent tried it that way but it should work. plus it would serve as a guide as to where the silicone should tapper down to nothing.

also having a small hole in the silicone tube with a nice angle is the key.

[jakdrob]

new silicone apparently does not stick to old silicone that well. you can cut out the silicone in the corners with out going in between the glass. and then re apply the new silicone. this can get messy. and isn't as easy as it seems unless you have experience applying silicone.

the trick is not to apply to much silicone in the first place. or use the tape method i havent tried it that way but it should work. plus it would serve as a guide as to where the silicone should tapper down to nothing.

also having a small hole in the silicone tube with a nice angle is the key.

I have re-siliconed several tanks now, and i learned a few things.... Remove all the silicone with a razor blade... then use rubbing alcohol and remove any residue in the corners,, u will feel the silicone left behind with a alcohol-wet finger.. make sure all seams are squeaky clean,, u gotta do sides and bottom if u wanna make usre it seals right,,, new silicone doesn't stick to old, so if u leave the bottom,, u will have a weak spot in the corners. I use black 100% silicone, I prefer black cause is doesn't show algae and doesn't stain. after all joints are clean and ready, mask off all seams.. make yourself a spacer the thickness you want,, eg 1/4" thick bead, I used a piece of wood I cut to 1/4",,, hold a razor blade against the space and use it to cut the tap so u get a perfect straight line and even thickness... then its easy, very quickly apply your bead of silicone,, I do the bottom first,, smooth it out with your finger,, don't push all the silicone out of the joint, u just need to smooth it out to look nice then run your 4 corner beads and smooth them out.. This should be all done as quick as possible,, silicone 'skins' over really quickly. shortly after, remove the tape. don't worry if u get some where u don't want it,, just scrape with a razor after it cures.. Leave the silicone to dry for several days,, if you can still smell vinegar, let it cure but more... its really not too hard and can turn an old looking tank with a sloppy silicone job into a nice new looking aquarium

[fleshgear]

where do you get 100% black silicone? i have resealed a few tanks, some i took completely apart. i dont use the masking tape method. i would prefer the black silicone but where to find it. and the stuff from the lfs is too much money. i use clear ge silicone 1 windows and doors

[jzz30tt]

Here's where the big GE Silicone I and GE Silicone II debate begins, First of all either would NEED to be window and door. Not bathroom and kitchen. The bathroom and kitchen is guaranteed to have several mildew retardants which also have that nasty side effect of killing our fish.

Many say that GE Silicone II will kill off your tank. But there is also a lot of confusion over which tube of silicone II they hold. There is an older one that doesn't include any mildew deterants or guards and this is one that i have used personally with 100% sucess. No sick or dead fish. However one of the big differances between the two GE silicone's is the base that they are dissolved in. GE Silicone I is based on an asetic acid hence the more smelly vinegar like scent that permeates from it. GE Silicone II is based on ammonia instead which is a compound which we all know and love. However the trick with ANY silicone is allowing it to cure FULLY. The full cure time on these silicones is in the area of 3 or 4 full days. I prefer to wait a full week. Waiting isn't something fish keepers tend to be terribly good at but if you just pretend it's procrastination you might be able to pull it off.

It's the release of these solvents that are what is harmful to the livestock in the tank. If we wait for a full release of all the solvent present and cure of the silicone we don't run into that issue. There is a risk inherent to using a product that on the packaging specifically says "NOT FOR USE IN: ... Aquariums..." The general understanding is that GE actually makes the silicone for several large manufacturers but has recommended that their own silicone is not used for aquariums to limit liability as well as to point people to the purchase of an inflated price on the Aqaurium only types of silicone.

There are several safe options such as the All-Glass aquariums silicone which i believe is sold at a lot of LFS including Big als. It comes in a black.

Anywhoo... i'll stop rambling now since i'm new here...

[Just_Relaxin]

I have resealed many tanks as well as buildings. I prefer Dow corning 795 as this is a structural silicone and if the tank is cleaned properly you will never have to recaulk again. If anyone needs to get some I get a real good price on it and it comes in any color you want black, clear, gray and so on. Feel free to pm if interested.