does the patch gain any structural strength if I manage a way to attach to the front as well as the side? I'm imagining the bicycle tire, and having trouble translating it to a square (it was a great example for what you were conveying, but imagining the same forces on a square is leading to problems for me..What I'm struggling with with that is whether the anchor to the front strengthens the patch by not allowing it to shift, or if it ends up weakening things because as the water tries to push the patch through the weak point, it would pull at seams for the front and the bottom...
It would help, but you might have trouble with the fabrication part. If you leave the factory edge against the front you should be fine.....
I can't seem to stop with the questions... If I get a piece cut for the side, since its basically just a 2x2 square it doesn't seem like that would be a big deal, would I be able to lay the tank on its side, and re-seam it the whole way around? Leaving the existing piece in place that is.. I care about strength not appearance since the side is going to basically be against a wall...
Would leaving the original piece leave room for the crack to continue to the front and back, even with a full replacement on the inside?
1) You'll have a tough time replacing the whole side.... it's difficult to cut accurately, to dress the site, and then to redo that panel... Acrylic is not like glass. Not at all.
2) The rest of the panel is not damaged... only the impact point. Perhaps a different example would help. Take a paper bag.... get a pen or pencil. Stab the paper bag on the side. Now imagine filling it with sand, popcorn, rice, whatever.... the contents would leak through the hole you just made. Now, how would you patch the hole? I would glue a new piece of paper to the inside.... wouldn't you? Acrylic is the same way. Leave a little overlap, make it look decent.... if you can glue to the front do it.
The only difference is that acrylic is thick, so we can melt some of your cracks with really thin solvent.... before we glue on a patch for the sake of over-fixing it.
I seriously doubt your tank will blow apart. Water is not dynamite. I once had the displeasure of finding my 27' sailboat filling with water. My imagination and fantasies had a flooding boat as being really dramatic. It wasn't. It was like filling a pool, a slow event. If anything the boat was more stable 2/3rds full of water. We pumped it out, found the offending hose and clamped it shut. Insurance bought me a new teak floor and everyone was happy. The sailboat weighed 8,000 pounds and had a 3/4" hole in it.... it wasn't shooting through the floor or anything like you see in the movies. It was gurgling in slowly but relentlessly. I suspect any leak from your tank would be slow and relentless..... not catastrophic.
The chemical weld is as strong as the acrylic... so the seam isn't coming apart. The cracks are impact damage.... think of it as crazing on steroids. If you melt the acrylic, some of them will go away, forming a water tight seal.
As I mentioned before, if it were my tank I would WO3 the inside, the outside, and then I'd fill it with water and slosh it around with my hand real hard or enlist a child to play in the water. I'd give it a few days and if nothing happened I'd install the tank.
If I found a leak, I'd use WO16 on it next.....
and the, and only then if it failed to fix, or if a piece came loose, I'd put a patch over it.
Let me make another analogy.... if you had a 1.5" bulkhead you would have a 1.5" hole right? If you wanted it gone, you'd simply cut something slightly bigger and glue it in... right? Well, the "hole" in this case is microscopic..... so it may not be necessary to put a patch on.
If it doesn't make sense just ask and one of us will try to explain. There are no bad questions...
