300G Acrylic Repair

Hey guys. I need some input on a dilemma I have. I currently have the opportunity to purchase a 300 gallon acrylic aquarium with a built in over flow chamber. The only problem? There is a 15 inch long crack in the bottom pane. I have heard this can be repaired but I don't know much about it. A search of the web isn't exactly giving me good ideas. Any input, advice, warnings, ideas please? Thanks

 

I would never trust a diy repair on that. Repairing a crack is just going to have a weak point, and a crack that long on the bottom is just going to be a disaster when it goes again.

 

Thanks for the input. I was thinking that maybe I could run some Weldon into the crack. Since it is on the bottom I also thought I could then add a piece of acrylic over the top of it and weld it to the bottom of the tank. You would never see it under sand. And maybe reinforce the crack?

 

I think in the bottom of a tank, your repair idea should be fine. We've patched acrylic a few times this way (Weld-On in the crack plus a patch), and have never had one fail. Since it's on the tank bottom, and the patch inside the tank, I'd say it will be plenty-well supported in this case.

 

Thanks for the response. I plan to pick it up this weekend. The spot that concerns me is where the crack meets the overflow chamber. Will this be a problem with sealing and patching? Thanks

 

Also, do I need to use a patch the same thickness as the bottom pane? I think the thickest around this area is about 3/8".

 

Does the crack run under the overflow wall or just up to it? I'd be a little concerned in that case, as any part of the crack that isn't sealed/supported might propagate.

3/8" sounds awfully thin for a 300 gal setup, altho I've heard that some tankmakers use thinner stock on the bottom of their tanks. I'd suspect that tank should be at least 1/2" thick, but to be honest, I had our 7' x 2' x 2' 210 gal built out of 3/4" stock so it won't bow. That being said, 1/4" is OK for the patch, as it's going to bond to the bottom panel anyhow, but 3/8" is fine too.