Re-siliconing a tank...

bradleyheathhays

Got a used 125 gal and I'm not sure if it's gonna leak or not when I fill it. Say it does leak, what is the procedure to re-silicone a tank? I assume it involves getting all the old silicone out and redoing the whole thing.

Is there maybe a tek on this? Thanks!

GwenInNM

I'm sure you'll get lots of support on doing this. You don't have to remove all the old silicone, but with a razor you carefully cut away as much of the old stuff as you can, without cutting into the actual seal. Buy aquarium safe silicone, and it has directions on the package. It's not hard, and is worth considering if the tank is that old. If not, I wouldn't bother doing it if it holds water.

Gwen

AbbeysDad

Be sure to use aquarium safe silicone. Or you can go to any big box or hardware store and get GE 100% CLEAR silicone I or II.
Clean the glass and rinse well. Sometimes old aquariums are pretty cruddy. A scotch guard like pad works well. Use a single edged razor (w/holder is nice) to remove any surface silicone all around being sure not to penetrate the seal between the glass panes. Carefully remove all of the old silicone. Clean well with rubbing alcohol. Ensure it's totally dry, then run a bead of silicone around the bottom first. You can be more generous (and messy) around the bottom since this will be covered with substrate. Last do the corner bead in the sides. Be neat here as of course it will show. You may need a finger or tool for a good looking bead. Let dry for 24-48 hours at room temperature, then leak test.

Any old tank, especially if it has sat empty for a long time will benefit from a silicone (reinforcement) reseal.
There are some that feel that the tank's glass panes should be disassembled and then resealed, but this is rarely necessary and requires some frame tools and clamps and is not really a DIY for the average Joe.

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bradleyheathhays

Thanks for all the help!

I've read a couple teks on doing this now and feel like I can get through it fairly well. The one question I have left is about striping the silicone from the top. Every tek I've read talks about stripping out the bottom silicone and the inside corners, but not the top. Since new silicone doesn't seal to old silicone there would always be some leak potential at the top corners where the new and old silicones meet.

So, question is...When stripping out the old silicone is it common practice to cut out just the bottom and the sides, but leave the top in tact?

Thanks

PS Since GE Silicone I and II are now both 86-ed, where do I go for caulk gun sized tubes of aquarium safe silicone. Fosters and Smith maybe?

Tazman

You want to remove as much silicone as you can from EVERYWHERE you are going to reseal, if it is one side you are doing then totally remove that side...if you are doing the whole tank, start on one end and then work across the rest of the tank..reseal the bottom first.

Some LFS carry caulking gun sizes of aquarium safe silicone. I have never had a problem using SCS1200 black silicone which I can get from my local one, some hardware stores carry it under the basement waterproofing section...

Fosters and smith have it here

zof

I'm assuming by the top you mean the silicone that holds the frame for the hood of the tank correct? If so reason most people don't bother with this seal is because it really has no load bearing or water proofing function as its purely ascetic to keep the hood frame in place. If the silicone there looks nasty then replace otherwise its fine to leave it be.

PonyMan

And ALWAYS use your finger (my preference) or a beading tool of some type (to me pushes too deep into the bead and you end up with a thin bead) to smooth the silicone into the seam. It makes sure the silicone goes into deep areas and you end up with a nice bead too. I'm a glass man by trade and have done hundreds of reseals on tanks and even built quiet a few. Made the 30g I have and did it with a solid mirrored back. Turned out very nice. It's really not as intimidating as it may "seam"! LOL Pun intended! :P

FranklinS

I would use Momentive (they bought out part of GE silicone) RTV 103 or RTV 108 (clear or black). You can get it through Grainger. Amazon is way too expensive in the larger size. Let it cure for about two weeks.

beetlebz

youre so fired.



Could I talk you into a picture journal of the process? We cant have enough of those!