How to repair seams in acrylic overflow?

[stgla]

I have an empty reef-ready tank with corner overflows and I want to turn it into a sump. When I pour water into either overflow it streams straight into the tank from the bottom seam.

Obviously I don't need the overflows, so if it were easy to remove them I would, but I can't figure out how to do that safely.

Can I just try to repair the seams where the overflows meet the tank bottom? If so, how best to do that?

There is a part of me that want's to keep the overflows in place in case I later want to sell the tank as a reef-ready display, but maybe I should give up on that.

 

[mcgyvr]

Its likely just silicone holding the plastic into the glass tank..
A razor blade will easily cut it free to allow you to remove the overflows..

 

[Vinny Kreyling]

You have to remove the silicone from the bottom seam & clean the surfaces with acetone (nail polish remover). Then run a new bead around the area. I would also plug the holes on the bottom just in case. You will have to build something so there is no weight on the plugged holes.
NOW, if you are adding baffles it would be very difficult to sell later as a tank.
If you go that route just silicone a piece of 1/4" glass over the holes inside & there are no worries with laying it flat.
Removing might be a pain but just cut the silicone seams with a razor blade.

 

[stgla]

Do they really just use silicone to attach acrylic box to the tank? I can't see any seams and I feel nervous just randomly slicing at the seam with a razor blade.

Good point about baffles. So if I'm committed to this being a sump, I really ought to remove the boxes but I can't see how to do that. They appear welded on, despite the leaks (both corner boxes are leaking).

 

[stgla]

I should have clarified that the *tank* is acrylic. Sorry, I thought I had mentioned that!

 

[mcgyvr]

If the tank is acrylic thats different..
The overflows are solvent welded then to the acrylic itself..

You could use a product like Weldon 16 to attempt to fill the open cracks.
That product is a thicker bodied solvent much like a glue that has "some" ability to fill larger gaps.. Anything bigger than 1/32" or so may require a repair where you bond another piece of acrylic over the seam with more solvent.

You could "easily" (well.. easy for the moderately skilled handy people) remove the overflows with a dremel cutoff wheel

 

[Vinny Kreyling]

As mcgyvr has stated with acrylic.