My potentially giant folly tank project - help!

[oenology]

Well, I just bought this tank - for my first resealing project it's a doosey. In fact I'm scared Sh...tless. Redoing the inside seams should be OK but I'm worried about these bubbles between the 2 panes of glass. They're near the bottom and they move a bit if I put pressure on the edge. The silicon bead at that point is about 1mm thick. There is also no reenforcement around the top of the tank. Any thoughts on whether or not to dare to put water in this beast if I reseal all the inside seams?

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[FishPassion]

I have resealed a few tanks in the past the 60 gallon being the biggest one, I really hate to say one way or another, if it works your a hero and if it doesnt yer a well u know. Personally I would chance it yes, but would like to have some reinforcment frame around the bottom of it made out of welded steel that the tank would slip into tightly and then sits on your stand. How many gallons is it???

I had to come back and add that the frame would almost have to be perfectly flat and made out of angle iron, but I would allow and put a fairly thick rubber material on the bottom of it to reduce the possibility of any unevenness and provide some relief on pressure points. Was this a custom built tank in the past?     
Ummmmm how come u didnt start with a simple reseal like a 10 gallon it does look like a nice tank tho
I personally am afriad of getting a tank that I can fit into as I always have thoughts of my wife sealing  it and burying me in it as a final resting place

[Saltcreep]

Well, the biggest I ever resealed was a 90 gallon about a year ago. I had to completely disassemble it when the bottom cracked. I actually patched the bottom glass rather than replace it but that's for another thread. Personally, unless it was a very small tank, I don't think I'd do a reseal without a complete teardown. That is the only way I'd feel comfortable with the seams. For a job that size, the most important thing you'll need are a couple of competent helpers. The two biggest obstacles will be removing all the old silicone and surviving the incredible stench (and toxicity) of the acetic acid during the resealing part. To remove the silicone residue, the best thing I've found is Contact Cement Thinner. It contains both acetone and toluene so good ventilation is a must. Using gloves that won't be dissolved by the solvent, apply a little bit on very fine (0000) steel wool. Gentle rubbing will remove the residue. Trust me, if you're gentle, you won't damage the glass. You must remove all the residue or the new silicone won't stick.

Another quick tip. Strictly through trial and error, I found the best way (for me) to take the tank apart is to 'chop' the old silicone rather than slice it. Leaving the inside bead intact, take a one-sided safety razor blade and either clamp it in a holder made for the job or a pair of Vise-Grips. Now, starting at the top of one corner seam, just lay the edge of the blade along the thin bead of silicone and push the blade straight in. Don't try to slide the blade because it will bind and you run the risk of chipping the glass. Once you've pushed the blade all he way in (should cut a half inch joint) pull it straight back out, move down the width of the blade and repeat. When you have completely severed all the silicone joints, wrap some fiberglass reinforced tape around the whole tank. One band near the top and another near the bottom. Now, with the tank secured you can work on the inside fillets. For those I used a utility knife and just slid the blade under the silicone and in to the corner. If you start your cut at the bottom, it's relatively easy to slice this bead just by drawing the blade up while pressing it into the corner. Now, enlist your helpers to hold everything while you remove the tape. It should simply fall apart into five easy pieces. Wasn't that a movie?

Anyway, hope that helps. I'd go for it! Good Luck!

[babblefish1960]

That is a nice shot of you lolling about in the glass box oenology.

I have resealed some very large tanks in my day, successfully I will add, the latest ones being a 130 gallon and a 300 gallon tank. Little ones leave lots of room for forgiveness, but there aren't the same level of forces involved, whereas the larger tanks cannot be trifled with.

You have something 40" deep, that takes the risks up to an entirely new level that very few aquarists ever experience, deal with, or are possibly even aware of. I won't go into the physics of it, but it is important enough to take precautions.

Dangling participle, sorry about that.

The pressure exerted at the base of the tank is considerable relative to regular 24" tanks, so much so that the silicone is being asked to withstand a great deal more than in other shorter tanks. It stands to reason that the tell-tales of silicone shear failure pending are both imminent and rather obvious near the lower sections of the tank.

To begin, as you are already doing, continue removing the inner silicone fillet from the interior corners, this will require a lot of razor blades to remove it cleanly without marring the glass. Once you have removed all of this silicone, it will be time to re-evaluate the condition of the mechanical bond of the silicone between the glass butt joints.

The best mechanical bond comes with a very thin layer, if there is too much space, the silicone becomes too susceptible to shear failure. This is because of it being so near the limits of elasticity. In other words, and this is why hexagon tanks fail when they don't have ground edges with the largest mating surface, the glass must be in good square and with an even surface to mate.

Perhaps you would like a visit from Mila, or me, or both of us to come out to have a good hard look and discuss your next move. It would seem that some serious thought will have to go into the safest and most cost effective way of making this a viable and reliable show tank.

Suffice it to say that something can be done with it to make it a workable tank, you just need to decide what the best course of action to take would be. Good luck with this DH crazy making project.

There is no problem so large that can't be solved by throwing large enough sums of money at it.

(edited for grammar and spelling, doh!)