Just curious, not arguing, but what do you mean? Every high end tank 4' or longer than has a center brace and not euro brace is simply a piece of glass silicon across the middle from front to back.
No offense taken at all. It's hard to discuss things if people don't ask questions, after all.
Here's a side profile diagram of the repair you're talking about, as I understand it.
(sorry for the low contrast, it didn't survive the jpg conversion as well as I thought it would)
The details may be slightly off-I wasn't sure if you were saying that the glass should be cut to the exact width of the tank or just wide enough to bridge the gap caused by the break in the brace, but either way the principle is basically the same.
When you glue the brace in there like that, the load from the water pressure is transferred from the old, broken brace to the glass through the silicone. The reason that this makes me uncomfortable is because I just don't trust silicone in this application.
The layer of silicone adds a certain amount of "give" to the brace that probably wasn't there when it was a single, rigid piece of plastic. Silicone is stretchy and pliable and as the tank fills and the plastic pieces start to pull apart, it's going to allow them to move a little bit before the glass support sees any of that load. A 55 with the standard brace might bow say, 0.125" when it's full. (I'm just pulling these numbers out of thin air by the way, they're for illustrative purposes only) while the silicone might add enough stretchiness to the brace that after the repair, the glass is bowed out by say, 0.2". It's just not a completely rigid (or very nearly so) coupling in my eyes the way it was before the repair.
And also, silicone is not very sticky. Very few adhesives stick to glass or plastics well, but it doesn't take much time or effort with a fingernail to be able to start peeling up the edges of the seals on glass tanks. Besides the additional flexibility in the brace, I just don't trust it to bond the glass and the plastic while dealing with any meaningful kind of shear force for a long period of time. And what happens if the silicone can't deal with the forces involved and one side of the brace just lets go of the plastic over a matter of 5 or 10 seconds. The front and rear of the tank are going to lose all of their support in a very short period of time, causing them to bow very quickly, which would seem to me to be the ideal situation to put the glass in if you want to see it shatter or one of the other seals fail.
It might hold for months, it might hold for years. Obviously, if this is how eurobraced tanks are built (I haven't looked at one closely in years, I don't remember), it works. But it does not give me a warm, fuzzy, comfortable feeling of safety when I look at it. If it were me and I insisted on repairing it, I'd get a 1/8"+ sheet of stainless, drain the tank completely, slather it in epoxy or superglue or something and glue it to the existing brace, wait for it to dry and then rivet or bolt it to the plastic.
I may be completely :screwy: and paranoid, but I intensely dislike cleaning up large volumes of water from my floor and using silicone to hold the two sides of the tank together like that just makes me really uncomfortable.
Now, having said all that, just as I finished this post happened to glance at my 30G and remember that the plastic frames on smaller tanks aren't really structural elements as far as I know-they're held together by the silicone beads on the seams. Thus, preventing bowing is probably the only reinforcement provided by that plastic frame on braced tanks, and if a tiny bead of silicone between the panes of glass is enough to hold the tank together, a 2" wide bead along the brace would probably work just fine. Which would make my discomfort at the idea completely irrational and illogical. :duh: That doesn't make me feel any more comfortable with it though.
