Re-sealing an 37 gallon

[Floyd R Turbo]

I just bought a 37 gallon off Craigslist for $20 and once I cleaned it out (dead bird and all) I found that it looks to me that the previous owner (who left it in a shop owned by someone else, so no history) apparently got a little too crazy with the algae scrubbing, the silicone on the corners is rather jagged and thin in a couple places, big tears out of it, etc. I haven't filled it up yet to see if it hold water, but I can't imagine it won't. Still, it's bad enough to me that it probably needs re-sealing. This is something I've never done before though, and I read this on another thread...

Well, if it were me, I would have bought the tank. It's REALLY easy to reseal a used tank if there are 0 cracks. You basically take a few razor blades, a bottle of alchohol and a clean towell.

Cut the old silicone completely off the aquarium, being sure not to actually stick the blade between the joined glass. Then go back and clean it all with alchohol and dry. Once completely dry, go back and put a 1/4" bead of silicone on each joint/edge, use your finger or a caulking tool to smooth out the silicone, The idea is that a little bit of silicone in the right place is better than a lot done sloppy. If you take your time, you have a 100% chance of sealing up that tank.

...and it sounds relatively easy to do. I'm an engineer and a fix-it guy, so this makes total sense. The last 37 I had (20 years ago) lost a seal and I paid a guy to redo the whole tank and it was thick and sloppy IMO. So I had a few questions before delving into that:

1) Can I run a bead over the existing seal or it is just better to take it all off?
2) What kind/brand of silicone would I buy, where would I get it, and about how much should I need? I'm thinking 1 tube would do it for a 37 at 1/4" bead
3) How drying time before putting water in?
4) Should I take off the top casing? I'm guessing it would be better, but as long as I can get the new seal up to the casing, water won't get over that. Assuming bottom casing can stay where it is since I'm just re-sealing the inside.
5) Do I have to worry about air bubbles in the caulking, like at corners, etc.
6) how tough is aquarium silicone to work with?
7) should I just fill the tank in the garage and wait a month, and if it holds, just leave it? Or is it safer than sorry just to re-seal it, especially if it's not that difficult?

I'm hoping it's not too difficult or expensive, because I like the size of the 37 and I got it so cheap, talked him down from $30

Thanks for any advice!

 

[thominil]

1. New won't stick to old.
2. Either get it from LFS, or GE has some that is aquarium safe. I thinks it's either GE 1 or 2, don't know right off the top of my head.
3. Letting the new silicone cure for a week is best IMO.
4. Just remove the stuff in the corners all the way up to the brace and reseal it. Leave the brace alone.
5. Yes, you need to worry about bubbles BIG time.
6. It's basically like glue when it comes out of the tube.
7. Just fill it and let it sit for a few days, if it holds, you're all good, if it leaks empty and find the leak.

Silicone is cheap, shouldn't be more than $10 a tube.

Hope this helps.

 

[mfdrookie516]

1) It would be best IMO to take a razor blade and remove the old silicone first so the new silicone has something better to bond to.

2) You can get "aquarium sealant" at most pet shops, or you can get #1 silicone at most hardware stores. Its all the same, and most will say "aquarium safe" on it.

3) Its best to let it cure at least 24hrs, 48 would be better...

4)That wouldnt be necessary, it would be very hard to do so, and you may end up breaking it trying to get it off.

5)Take your finger or one of those plastic "calk" scrapers to get a nice bead all the way around and you wont worry about air bubbles.

6) Silicone is very easy to work with, but if you get it on anything, you will have to let it dry before you can remove it easily.

7)It would be well worth the $10-15 to reseal it now, instead of having to worry about it leaking later down the road, then having to take the whole thing apart, reseal it, and put it back up... JMO though

 

[Floyd R Turbo]

Thanks both for the advice. I read up on it a little more and it doesn't sound too hard, and I think it would be worth doing instead of risking a leak or failure down the road.

I have another question though:

After you remove all the old silicone, you should clean the glass but I've read using rubbing alcohol and I've read to use Acetone. Will either of these dissolve the silicone seal that I'm not removing, that is, at the actual joints? Is one better than the other?

Also, if I do end up with any bubbles anywhere, do I pretty much just have to start over? I'm guessing that I'll be able to catch them and work them out, if I work fast enough (<5 minutes for the whole job)

 

[mfdrookie516]

I always use vinegar to clean my tanks. The last tank i resealed, i just scraped off the silicone, used a sponge and vingegar/water to clean it, let it dry for a couple hours, then siliconed the joints. IMO thats the best way, not sure about using isopropyl alcohol or acetone in an aquarium though, i know it was recommended in another thread not to use a glue on an overflow pipe that had acetone in it, so idk if i would risk it personally

 

[Floyd R Turbo]

I picked up a couple tubes of the All-Glass brand silicone, and they suggest using isopropyl alcohol. I did read that acetone can dissolve rubber, although it dissipates quickly so it really couldn't do much damage I guess. I'm guessing that's what they suggest using when you tear a tank all the way apart and you don't want any trace of silicone left, because I was reading a 'build-your-own' thread. The alcohol makes sure the glass surface is clean and dry. I don't know if vinegar would do the same, I know it's great for removing limescale and calcium.

 

[Floyd R Turbo]

Chip under seal

Ok, so I started scraping off the silicone, and I found a chip in the glass on the edge of one of the side panes, about 1" from the top. It appears to have been chipped AFTER the original seal was placed, because it came off with the silicone. It's about 1/2 cm long and would be completely underneath the new bead, and only 1" below the surface of the water.

Anything to worry about? Besides making sure no air gets trapped in the hole?

 

[h8z2luze]

I just picked up some made by DAP from home depot it was kinda hard to find but it says its safe for fresh and saltwater fish so i got it.

 

[Floyd R Turbo]

Anyone want to weigh in on the chip? I just now got done applying the silicone, it wasn't as messy or difficult as I thought, except the tube was pretty hard to squeeze towards the end, hand got tired! I got he caulk worked into the chip pretty well so I don't think it will be a problem, but the fill test will determine! No I just have to wait a week.

 

[mfdrookie516]

i would let it sit for at least 48-72 hrs then put it in the garage and test it for a day or two... That would certainly beat having water all over the floor if the silicone doesnt hold... jmo tho

 

[Floyd R Turbo]

Oh yeah, I'm going to wait at least 4 days, then fill & let sit for a good week in the garage to make sure.

I can tell you for sure that if I ever have to do it again, I'm getting a tube that can go in a caulking gun, because the squeeze tube sucked. I examined it a little closer and I think it is thin in a few spots, and although there's at least 1/4" of bead, there is a spot or two that didn't 'flare out' very much when I ran my finger across it. I probably should have touched up those spots before it skinned over but it's too late now. It's still better than it was when I got it.

Plus my 55 have a few thin spots like that, and those are original, it has no issues so I'm not worried too much.

 

[mfdrookie516]

The gun is the way to go, but its not really cost efficient for a smaller tank unless you plan to use it again... I resealed every tank i got that i didnt see set up, which if i remember correctly was two 55's, a 30, and a 10... I got kind of used to just buying one, then resealing it... my biggest job was going back with a razor blade and cleaning up the spots that i didnt make look so good lol... Sounds like you pretty much covered it, but it is a good idea to test it first

 

[Floyd R Turbo]

Need quick reply please!

Another question, after the first 24 hrs I ran my finger across all the seams, and have found a couple spots, maybe and inch or so long, where the silicone isn't flared out much more than 1/4" from the corner itself, in other words, I ran my finger along the bead but in a few spots it just smoothed the top out and pushed it into the corner better, but it didn't goo out around my fingertip. Both of these places are along the bottom, one at the front edge, one at the back. That's where I started, and since it's a 37 with black trim, I couldn't really see that it was too thin. Is it too late to dab in some extra silicone in those spots?

One previous poster said new won't stick to old, but will new stick to 24-48 hours old?

Need some advice ASAP on this one.

Thanks

 

[mfdrookie516]

its worth a try... why dont you take some really rough sandpaper and run over the spots that need "touching up" and then the silicone will have somethign better to bond to... its going to have water pushing against it, so i dont see a problem with those spots...jmo tho

 

[Floyd R Turbo]

I guess I don't know if roughing it up would work very well, because how do you get the little bits of cut up silicone 100% removed so that there will be no air bubbles?

I'm leaning towards cutting it all off and doing it over and calling it a learning experience. It took me quite a while to get it ready the first time, and I'm guessing it's going to take longer with freshly bonded silicone. It is possible to cut away only the sections that need to be redone and leave the good portions alone? The vertical corner beads look fine, it's just sections along the base that are thin, and they're thin enough after looking at the closely that I think they need to be redone, but not 100% - the corners are fine, it's just along the edges.

 

[mfdrookie516]

i did that on one of the tanks i resealed... i just left the bead going down the corners and resealed only the bottom... worked fine for me... not sure what other people will say, but as long as you do an extra goopy corner, i wouldnt see a problem with it

 

[Floyd R Turbo]

Thank you mfd, you have been a great help with all my questions. I can tell you've done this quite a few times. I didn't get the corners really super goopy, probably because I was going for time (< 5 min) and really didn't know what I was doing. I think I'm going to shop for the DAP tube at Home Depot and use my caulking gun and get it right.

I guess if anyone else reads these posts in the future, I can tell you to go liberal on the silicone around the bottom and the corners, too much is better than not enough since you don't see that part anyways, then to make sure that you flare the bead out on the vertical seams enough to bleed out about 1/2" from each corner.

The seal that I removed was really thick at the base and the edge was 'rounded' like it overflowed from around your finger, and the edges were more thinned out and pretty/presentable.

 

[mfdrookie516]

i used a plastic "wedge" when i did mine. I got a few when i was helping my dad calk around a bathtub... it has 4 corners with different angles and you can pretty much choose how you want the bead to look and keep it perfect the whole way around. Any hardware store should have them. I dont know if i mentioned that before. Sorry i havent given you the best answers, im still new at this. But i have done this before, and learned that with silicone, you can always use too much, its just like wood, cut it too long, its ok, cut it too short, gotta start all over

 

[Floyd R Turbo]

I bought one of those, but it wasn't the multi-tool, it was just a soft-edged rounded scraper and it didn't contact the silicone bead enough so I switched to my finger. I guess I should have taken that as a clue.

 

[Quartz92]

"then to make sure that you flare the bead out on the vertical seams enough to bleed out about 1/2" from each corner."

I have a question regarding the above quote.
1)Whats a bead and what is the point of flaring it out.

I am planning to reseal a 55g.