How to seal a hole in a tub

[thomas]

Hi,

I got a 75 gal tub that i would like to use a a goldfish pond that look like the one below but it have a hole in the middle about 3 inch diameter. I was wondering if anyone got an idea on how to seal this hole up. I was thinking about buying a acrylic sheet and use some kind of glue to seal it up from the inside of the pond. I'm pretty sure this would work but I want to get some advice first before doing that. Please give me some advice.

Thanks

http://www.tsekoi.com/tanks/images/rectangle.jpg

[bekko]

It sort of depends on where you will put the tub and the ramifications of a leak. A tiny leak outside in the garden is no big deal while a tiny leak in the upstairs bedroom could be pretty bad.

You will not find a glue that sticks very well to polyethylene. Silicone from the hardware store will hold for about a year, aquarium silicon will hold a little longer. If you accidentally hit the patch or twist the tub it may start leaking.

For more security, you could use a piece of acrylic, a rubber gasket, three bolts, three neoprene washers and three nuts. Sandwich the gasket between the piece of acrylic and the bottom of the tank. Use the nuts and bolts to hold the sandwich together. Use aquarium silicone like mayonnaise between every layer of the sandwich.

You could also take it to a car body shop and have them thermal-weld a polyethylene patch.

Another option is to put a bulkhead fitting in the hole.
http://www.aquaticeco.com/subcategories/2985/Bulkhead-Fittings-Economy/bulkhead/0. Then, use a standpipe or threaded PVC plug.

There are these too ...
http://www.aquaticeco.com/subcategories/3211/Hand-Tite-Plugs/hole%20plug/0

I would just use a piece of acrylic with some silicone and plan to have to fix it again in the future.

-steve

[thomas]

Hi Steve,

Thanks for the ideas, I'll try the bulk head fitting method. That way I can drain the water when needed.

[Fishdork]

Polyurethane caulk such as Sikaflex 1-A sticks pretty well to things like plastic barrels (and the pores in your skin, etc). Use it as a gasket, not as a weight bearing patch.

When I put bulkhead type shower drains in the lumpy bottoms of barrels, I cut gaskets out of a closed-cell foam sleeping pad. Cut inner hole undersized because it stretches and coat both sides with Polyurethane caulk.

Norm

[Cincy Ranchu]

I have tried everything but the bulkhead fitting, I finally just put a piece of scrap liner in the 150g
Anybody ever try Gorilla glue and a piece of PVC?