Tank reseal question

I was looking at a used tank I'm about to set up and decided it needs a reseal. I'm thinking of using black silicone instead of clear as I have always like the black seal tanks. My question is regarding the corner overflow area of the tank. I have removed the outside layer of silicone from the overflow but it's still solidly stuck in place. Should I bother removing this to reseal the complete tank? The silicone in this area of the tank looks ok. Is there any trick to removing it if I should need to remove it? If I leave this area alone could I just remove the silicone in the corner (where the sides meet) and leave the bottom silicone as is(so it will match)? If I don't remove the overflow I can't get the silicone on the bottom.

Any help would be appreciated.

Any recommendations on where to get black silicone that's the size for the caulking gun?

 

Make sure you use electrical tape to make sure you get fully straight seams. The black silicone will show minor mistakes a lot more than clear silicone. I wouldn't remove the overflow because it will darn impossible to get the inside siliconed properly.

I did some googling for you for AGA Black Silicone. The product you're looking for does exist but the first 4 or 5 web pages that had it said it was out of stock.

 

to properly re seal the tank you NEED to remove the entire inner seal...new silicone WILL NOT adhere the old silicone that is contaminated with years of god only knows what...

the box will have to come out..otherwise i can guarantee you that the tank will leak where the new meets old. Once the structural seam of the tank is exposed to water it begins to degrade and it is only a matter of time before catastrophic failure happens...

resealing a tank is not as simple as pulling the old silicone out and laying a new bead in...the cleaning and removal process is painstaking and tedious...it takes a full boox of at least 50 brand new razor blades and a good gallon of acetone to remove the silicone residue left from the old seal...any less and it will fail...even meeting the simple guidelines of resealing a tank doesnt mean it wont fail....it is never the same putting it back together...

dont use electrical tape, use blue or green painters tape to edge the new seal..

as for silicon, the best stuff to use, and the only stuff i would use is RTV103 (black) or RTV108 (clear), or SCS 1200, they are both structural adhesives (what the professionals use to build tanks) and are not simple consumer grade sealants like the AGA silicone...(and no they dont build tanks with this stuff, they may seal small tanks but certainly wouldnt build with it.)

in short: resealing is not a quick nor easy nor simple fix....all 100% silicones are not created equal use the proper stuff and do it right...if you have only a 100 hours into cleaning the glass you are only a couple hours short of doing a good job...

 

Thanks for the response. I definately understand it needs to be cleaned and plan to use painters tape to keep the lines straight. Thanks for the info on the silicone. I was able to find the RTV103 pretty easily online.

I'm a bit concerned about your statement that it requires 100+ hours to reseal the tank. If that is the case I cannot possibly see any logical reason to even bother trying to reseal it. It's not a cheap tank as a new 45gal oceanic will easily run me several hundred $$'s but at 100 hours even looking at $10 an hour my labor alone would run $1000. I have no issue spending a good amount of time to make sure it's clean but that is crazy!

Do people typically go through this much effort to reseal a tank? If not do any of you have issues with the tank leaking?

Using acetone to clean the silicone, is there anything special I need to do to ensure it doesn't cause any issue with livestock or does it just completely evaporate?

 

There's your answer.

 

Thanks Inwall. I was concerned about pulling the overflow for just that reason. It is completely sealed in so I am not overly concerned about causing any leaks without removing it but I am far from an expert.

Thanks for the recommendation of the AGA silicone. I managed to find some on ebay oddly enough. You can find anything on there. I was also able to find some RTV103 which is industrial as recommended by nanoreefwannabe.

 

100 hours might be a bit of an exaggeration...but i wouldn't hesitate to spend a couple days cleaning it...you can also use a fine steel wool with the acetone to help scrub the film off...a couple rinses and any acetone residue will be gone...the overflow box might not leak but the two corners where the new inner seal meet the overflow box will not adhere properly and you are risking far more then i would...i have seen the damage that 20G of water will do to a house and spousal relationships..wouldnt want to be on the short end of a 45g spill...as far as time and monies spent to reseal a tank if often why it is not feasible to do it with smaller tanks...the process is exactly the same for a larger tank but the cost to replace a larger tank is far greater making it a reasonably worth while procedure...for smaller tanks the risk out weighs the cost and it is usually easier/ cheaper to just buy a new tank...to each there own...i enjoy the work myself and have actually spent the time to rebuild a standard 20g LOL...

as for the RTV103 it is readily available at graingers and mcmaster (dot) com

 

Thanks for the clarification of your prior post.

 

GE Silicone II comes in Black .. make sure to use the Window and Door..

Will be fine for overflows but would use GE Silicone I Window and Door for sealing the actual tank itself.

 

I definately enjoy working on things but have too many hobbies and work too many hours along with a baby on the way. I have been enjoying getting everything together on this tank and love to see things come together after the hard work. I am planning to replace the external seal on the overflow box but would rather not remove the internal (seal holding the overflow to the tank) if possible as I am concerned about getting a good seal between the tank and box. Not sure if we are talking about the same seal. It seems like the tank had the overflow glued/sealed in the tank before the secondary seal was added(not the seal holding the glass together). Please let me know if I'm not making sense. I've had a long day.

Is there a trick to removing the overflow box if it is necessary? I doesn't seem like it would be easy to cut the silicone seal out with a lot of trouble as it looks like a very tight fit.