To reseal or not to reseal...that is the question

[Keith Perkins]

Good luck! I bought some of the Dap you suggested. I'm going to use it to re-attached a new panel (between the glass) and then use the GE I to lay down a bead over the seams for one of the tanks. I'll do another with Prefecto Silicone from Dr. Foster/Smith and the 3rd I'll do all GE I.

P.S. How did you clean off all the old silicone? I've spent hours scraping with razor blades and Exacto knives. I started using the acetone to help find and soften the hidden silicone, so I could scrape it all off. A fine nylon scrubby and very fine steelwool also helps. If the seals fail, it won't be because I didn't get the old silicone off!

I'll be really interested to see how you make out with each of the products. On my first attempt I primarily removed my old silicone by spending hours with an exacto knife and a single edged razor blade. I followed that by cleaning with a paper towel and rubbing alcohol while checking for any missed silicone. I did the alcohol process six times as I recall. The cleaning on the second attempt was the same as the first except after the initial silicone removal I applied a thin layer of a caulk remover product. I didn't do the steel wool, as I didn't disassemble the tank. I will be doing it on the third attempt when I do take the tank apart. That may be a few months, as the yard work etc will be calling for a while.

[TookayS2K]

I'm in the same boat. I'm trying to reseal a 80 gal bow front. In my situation, I can't find the source of the leak since it's at the bottom. It was leaking some where near the bottom rear edges.

For my first attempt, the rear sealed perfectly... but then the front corners started leaking. I think my mistakes were some of these:

1. only waited 24 hours to dry
2. bow front makes it hard using the scrapper tool properly to smooth the silicone. This is because the edges are not 90 degrees all the way around the take. The tool is ment for 90 degree angles. I used the size 16 on the tool.. since it provided to largest bead of silicone.
3. I used GE1. I shopped at home depot and really couldn't find anything else situable. There was DAP but none were suited for the job.

I'm currently stripping all the new silicone I just put on... what a pain!

[Fishandturtlejunkie]

I re-sealed my 190 display tank. It was a nightmare. Partly because I was a novice at the time, and also due to the glass euro-bracing that made it extremely difficult to maneuver around inside of the tank with a caulk gun, razor blades and lacquer thinner for days on end.

I highly recommend using GE RTV108 (clear) if you are going to do it, and mask everything off after cleaning the crap out of the glass before beginning with razor blades and chemicals. This task is not for faint of heart, but if you are meticulous it will pay off in the end. Good luck!

[rickztahone]

it might be a dumb question but do you use silicone on the outside of the tank when re-sealing? i've pretty much taken all of the inside silicone off which was a PITA, but i'm sure i got it all. i'm letting it dry now and i will be re-sealing it with the GE I clear silicone, is this strong enough to hold, or do i need something stronger for resealing a tank? TIA

[John_Nicholson]

Any 100% pure silicone is plenty strong to hold a tank together. When resealing a tank remember that glass can never touch glass. If it does then it will leak.

-john

[Apistomaster]

Regardless of what it is you are trying to seal any leaks, be it an aquarium or a concrete basement, all sealing must be done on the side opposite of where the leak(s) appear. All attempts to seal leak from the outside are doomed to failure. I have plenty of experience with sealing leaking aquariums, underground concrete structures of an industrial scale and I have written technical specifications for public agencies sealing projects so I have a very good idea of what is and isn't possible. I have worked with virtually every class of sealants. For aquariums use only plain silicone sealant containing no mold and mildew inhibiting chemicals.

Any aquarium which has a leak should be emptied and completely dried before ever beginning the work. This is an extremely important point.
Sealing a leaking aquarium is about the simplest case.
Identify the source of the leak if possible then use a razor blade to remove the bulk of the sealant some distance from where you are suspecting the leak's source. It is actually best to remove all the interior silicone and do the entire tank including inside the top rim.
Once you have removed all the sealant you can using a razor blade then use acetone to remove any residual silicone.
Use the blue masking tape sold at all hardware stores to mask off the limits of the sealant and to obtain straight sealed lines. Apply the silicone sealant then immediately remove the masking tape as soon as all the seams have been sealed. You only have about 10 to 15 minutes of working time depending on the ambient temperatures. But be careful as the tape will curl and be springy. this can spread sealant where it will have to be removed after it has cured and again, remove any traces with acetone.
By sealing the entire tank you will know that the job was as thorough as possible. Normally if the sealant is cured for 24 hours the tank may be used. By using masking tape and spreading the sealant thinly, the sealant cures well within 24 hours and this is a waterproofing seal not a structural one as when building a tank so 24 hours of curing time is sufficient.

Do not believe any claims that a leak may be successfully and permanently repaired by applying the sealant to the outside.

[David Rose]

In my research, I only came across removing the silicone on the inside only, and to be sure not to cut into the joint seams. I didn't have any visible silicone on the outside...just around the plastic framing.

[MikeF]

Quick question. When resealing a tank, what do you guys use to smooth out the silicone with? Was looking at doing mine next weekend, and was going to ask this question on another post. I have heard to use a spoon or guitar pick. Any better ideas?

[chaoslite]

This is one area on SD that I actually have experience in. Unless you see the sealant crumbling in the seams on the outside tank, leave them alone. Apistomaster has it right. You are going to notice a heavy vinegar smell, so make sure you are in a well ventilated area. Outside is best. I just resealed a 60g. Personally I wait 48 hours for it to dry although they say 24 is fine. Fill it up outside after it has dried and watch for leaks. If you cannot do it outside put a big tarp under it. I leave the tank full for 24 hours. If you see no leaks you are good to go. If you do find leaks, I always just remove it all and start over.

Mishka

[rickztahone]

thank you all for your replies. i think i might have not been too clear, i was asking if i had to take the silicone off of the outside and reseal the outside (it only had a small thin bead of silicone), this is on top of resealing the whole inside of tank. i already removed all the silicone from the inside and i'm letting it dry out. i saw that the outside had some silicone but i left if on until i heard back from fellow members. thank you all again for your replies. this tank will not be in use any time soon, it will be for my RCS fully planted tank. the tank had a small seal but i do not remember where it was so i decided to do the whole thing.

[Jhhnn]

I'll agree with Apistomaster. I've resealed a few tanks, and use silicone seal often in my line of work. It's hard to overemphasize the idea that the surfaces to be sealed need to be scrupulously clean, free of residual sealant, and absolutely oil free. Silicone seal doesn't stick to the dried product well at all, or to the slightest hint of oil, even fingerprints.

Dap 100% silicone seal is also a good product, as is perfecto aquarium sealant, if the GE isn't readily available.

The tape trick is a good one, as is sealing up under the rim. If you've never done it before, it's a good idea to practice a little immediately beforehand on the inside of a cardboard box, for example, just to improve your technique... have enough sealant on hand to do the whole thing in one session so that the seal is one continuous piece...

I like to let it cure more than 24 hrs, but my technique is kinda blobbish, not the best, and it takes longer for the sealant to de-gas and set up when it's thicker...

I had the opportunity to buy a really old school tank, one with a chrome steel frame and slate bottom. I could tell it needed to be resealed... with what, I didn't know, so I passed it up... It's still there, and I'm still thinking about it... It's older than silicone seal, and the original sealant is like tar, so it has some oil in it, and I figure I'd never get the slate clean enough to have confidence in using silicone seal on it... anybody know what to seal it with to restore it to original?

[chaoslite]

rickztahone - you do not have to take it off the outside.


Hey Jhhnn check out this link maybe it will work for you. If not it was worth the try.

http://www.wetwebmedia.com/oldetkrepairfaqs.htm

Mishka

[rickztahone]

rickztahone - you do not have to take it off the outside.


Hey Jhhnn check out this link maybe it will work for you. If not it was worth the try.

http://www.wetwebmedia.com/oldetkrepairfaqs.htm

Mishka

hey John that would great if you are able to just put hot water in that tank to fix the seal

[chaoslite]

Well that might be a good trick...lol but I was thinking he could try what was suggested lower on the page for the tank with the slate bottom. The post is listed as:

MetaFrame Aquariums 8/16/07

Steps 1 and 2

Mishka

[Jhhnn]

Thanks for the link, chaoslite... interesting. The tank in question is too big to fit in the sink- it *might* fit in the bathtub for the hot water treatment... it's big

Good luck with the reseal project, Rick... it's one of those situations where "Cleanliness is next to Godliness" actually means something...