Aquarium silicone sealant comparisons

[Trouser Cough]

There were no extra plates. I've resealed smaller tanks in years past and this one is built in that same way; four walls and a floor that sits inside them with an aluminum top frame and an aluminum bottom frame. The tank was made by Custom Aquariums and seems to my eye to be built like a 55g on steroids. Stouter in every way but the general construction is the same.

...and a correction. I resealed this tank four years ago w/ standard caulking I bought at Home Depot. Standard but for no inhibitors.

So it looks like I may have dodged a bullet as far as plate and seam complexity goes. I would like to do this one more time and do it right, preferably by my own hand but this time w/ expert advice. My assumption is that my workmanship on the prior project was fine; my error was probably more toward not having asked for input regarding the proper silicone. I rooted around until I thought I understood but in reality all I knew was to avoid additives. I'm thinking I ran off half cocked and did a fine job w/ the wrong product. I'm not afraid to try again I just wish the time and hassle were a little smaller. Cost, too.

 

[Trouser Cough]

Might fetch a battery powered caulking gun to speed up the process. As I recall that was a ton of handle squeezing and a quick cure product won't make that any easier. Looks like there's one at the local hdwe store, too. Every time intensive project turns out to have been spendy in unexpected ways... like $25 tubes of caulk and a gun to slobber them out.

 

[Trouser Cough]

Man... there is sooo much work ahead before I can get to step two, Rescue.

I'm also pretty sure my wife will neuter me if this big boy pops a seam again.

 

[Backfromthedead]

Thats no easy reseal, Trouser Cough , way bigger than ive ever tried. I would say you definitely need the electric caulk gun, i personally wouldnt try it without it.

With the electric gun the actual reseal shouldnt be too difficult...but prepping the job, cleaning off all the silicone will be the challenging part imo. If you leave just one little smidge of silicone you will have all the same problems again.

Another potential pitfall is cure time. I know youll be anxious to get it filled, but on a tank that size i would let it cure for 3-4 weeks just to be safe.

As far as type of silicone i would probably reach for dow 795 for its superior workability and neutral cure. If i were rebuilding the tank structure i would use the stronger rtv108 or scs1200 though. Those are both acetyl cure so you will need to have those fans running and windows open awhile if you go with them.

For just the reseal, i would get at least 4 tubes, probably 5 to be safe. I am very liberal when applying silicone though, you could probably get by with less if youre very careful and neat.

This is a big glass tank. Its hard to guarantee success in your situation since youre not in a sterile workshop, presumably working by yourself, admittedly a novice. For me, given its history, this tank would have to be relocated to a garage or basement, somewhere it couldnt do more damage if it blew out again. In my mind it really needs to be rebuilt with a structural adhesive so the entire seal is one piece, maybe even with reinforced seams like mentioned above.

 

[Fish rescue]

so to be obvious , it's a euro brace that's on the floor , and 700 gallon , cover the top quite bit with reinforce ment (possibly identical to the lower armor) if its already got some standard brace yes use it and some .... , go slow , done right could give 25 years reliable. ....photos help

 

[jjohnwm]

Yikes, TB, this is not good to read. If I were you I would follow advice provided by Backfromthedead to the letter. His constructions...aquariums and also written sentences...look good and work properly.

Can you clarify something a bit? Are you dismantling this tank and re-building, or just stripping the interior bead off and replacing/resealing? You used the phrase "popped a seam" at some point; that implies one of the structural seams has begun to fail, which would mean a complete re-build IMHO. Adding additional braces on the bottom edges would be easy to add during a re-build, and using them vastly increases the area of the sealing surfaces and thus the strength of the completed construct.

Either way, it's impossible to overstress the importance of removing every last shred and trace of silicone from the glass beforehand; it is, IMHO, the hardest and most tedious part of the process, but likely the most important.

If you get a powered caulking gun, I'd suggest a fair bit of practice to get the feel of using it. After decades of working with manual caulking guns, I finally played with a powered one recently and ended up dropping it after a few minutes and going back to the old one. I simply had more and better control of the speed of delivery by squeezing the lever as opposed to manipulating the trigger on the battery-powered one. Buying a sophisticated rifle does not a sniper make; practice does.

In general, do not ever throughout this project use the phrase "good enough". Trying to cut corners and save a bit of time here or a bit of effort there will simply sow the seeds of doubt, and once they sprout you will never feel completely confident and comfortable about this tank in future. You want to sit back and look at the completed project and know it's perfect...rather than hoping that it's good enough.

I'm looking forward to following this project, and feeling thankful that I am just watching rather than doing...

 

[Trouser Cough]

I'm polluting a resource here by posting about my tank saga in a thread comparing silicones.

I'll start a separate thread and detail the project over the coming weeks of repair.

jjohnwm I may be a little ahead of the ball as far as what the real cause of the leak might be so take what I've said so far w/ a grain of salt. Truth be told I don't know where specifically the leak originated but thinking twice about it it's probably not a vertical seam. My slightly revised assumption is that it's probably one of the seems at the floor of the tank and I say that because the water is seeping out from inside the bottom frame. The tiny gap between glass and frame is wet and it's one corner of the tank that's the main leak spot but I don't know if that might be a zillionth of an inch lower than the rest of the tank. I'm guessing now that the leak could be coming from any point along the lower inside seam and migrating to the point that it becomes more obvious to me.

Details to follow.

My apologies for running a silicone comparo thread off on a tangent.

 

[Melfe]

I have made tanks out of Dow 999-A silicone and some of them are over 5 years old.