Redoing Seams on Old Tanks

  • #1
I've seen a lot of threads about repairs for cracks and on building tanks but nothing except for one reference by Mr Waxhead on just doing the interior bead.
The used 90 gal I just bought has been dry for about 4 years. Looks like it was once resealed, blue color, uneven beads inside, clear between the glass panes. Very dry and in spots bubbles and even pulling off in other spots.
I've used a blade and removed as much as I can possible can w/o cutting into the actual seam between the panels. Have cleaned with alcohol.
As soon as temperatures warm up enough at night (tank is in my garage), hopefully in the next week or two, I'm ready to reseal.
Anything else I should do? Any hints?
I got this tank for a pretty good price, even figuring the cost of the silicon. If it leaks, I figure I'll still get most of my money back selling for a reptile house given its size, then I'll fork out for a new tank but then I'll have to skimp somewhere else, like no plants for awhile til I can afford good lights.
Any suggestions apreciated.
  • #2
Just make sure you use aquarium safe sylicone. This is available at the LFS, or online from some place like , place a thin bead right in the corner, wet your finger and smooth the sylicone out in a smooth even stroke that fills the crack with even overlap on both sides. Let it cure for 48-72 hours, then fill your tank with water. If you have it setting on dry newspaper, and let it sit over night, you should know if it will leak.

If it doesn't leak, empty it out, before moving, and why not just use it yourself! Sounds like a good deal to me.
  • #3
You can run masking tape down the corner, 1/2" from the corner, apply the bead and smooth over with a wet finger to the edge of the tape, then remove the tape asap, and you will have a nice straight line..
  • #4
GE 100% Silicone II Clear is what we use here.
  • #5
I used regular clear silicone (permatex 66br) from an auto parts store without any problems. It's about half the price of the aquarium stuff from the LFS. Do not use anything that is labeled for bathroom use, as it likely has additives to prevent mildew.

As Peterpiper said, make sure you remove the masking tape before the stuff hardens, or your likely to pull the whole bead out with it. It's extremely frustrating, believe me.
  • Thread Starter
  • #6
Thanks for all the tips.

I'm really getting anxious now. Saturday the high was 68 and today it hit 72 but the nights are still too cold for sealing. Hopefully by next weekend it'll be warm enough. Planning on going to the city this week, will pick up the silicon then. Think I'll hit couple of the lfs and get my substrate. If I buy in increments maybe it won't seem like I'm spending so much money (insert a rolling the eyes smiley)

Oh yeah, saw my cabinet builder friend today. He told me to go pick out the stain for the cabinet while I'm in town, so that'll be something else fun to do and think about when I'm fighting traffic....I'm just a country bum...can't you tell lol!
  • #7
Sounds like a fun trip....lots to look forward to, and plan.

Speaking of smilies, do you know how to get them? When you go to the regular post reply ....not the quick post.....up in the top right hand corner of the screen is a yellow star with a on that and you can choose 50. When you save them, then they will come up every time you post to choose from, you can change them any time you like by just repeating the process.....I LOVE the smilies.
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  • #8

Tank is sealed and still holding water!. This morning I did the final top off and all looks good. Though we did have to add some blocks and 2xs under the center of the workbench the tank is sitting on in the garage.

Hubby still has to add some additional braces under the floor where the cabinet & tank will sit. Should be ready to start cycling by next weekend, if the cabinet is finished anyway, if not it will be soon.

GE II has "Bioseal" a mildewcide added it's "new & improved"
Glad I looked, I remembered reading in here somewhere that it was changed and one should use GE I now. Sure enough GE I label is only silicon. Someone that can should make a sticky post about this.
  • #9
is there an order?

I am having the same problem with a 40 long in my shop. Its been dry and in the hot and cold, so the bottom leaks. I've got the silicone and am ready to cut out the old interior seals, but I wonder??? Is there an order to the seams, as in, should I do the sides and then the bottom, or the bottom then up the sides. By myself and with the tank this long, I'm worried that the beads will tack out and pull loose before I get them all finished. Anyone know, or is the consensus to just go as quickly as possible? Lee
  • #10
You have about an hour before the silicon skins over, so should be enough time to get all the seams done at once. Just do all the prep-work first, tape the glass, if that's the way you want to go and then apply to all the seams before removing the tape. If it does start curing before you have time to remove the tape, run a sharp blade down at the side of the tape first, to make sure that it doesn't disturb the seal when you remove it. (Personally, I found the tape method a chore, and with care, it's not difficult to get a good finish without it, and much quicker too!)
  • #11
no tape

right don't lay a bead of silicone that's too big and don't pull too much away as you smooth it into the corner should I dip my fingertips in alcohol to keep the silicone from sticking or just keep them wiped off regularly ( as I am worried of the alcohol keeping the silicone from sticking to the glass)? Lee

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