dwhatley;161396 said:
Joe, I think that is pretty much the same (other than using glass - good idea if she can get it drilled) idea as my original sketch - correct me if I missed something - instead of acrylic).
Sorry D, I missed seeing your sketch. Where is it?
dwhatley;161396 said:
Neal also confirmed that a gasket on the outside of the tank does nothing.
YIKES! Not true.
dwhatley;161396 said:
Katy, the back glass piece [...] is NOT for sealing the tank, the silicone on the inside between the overflow box and tank wall will seal that gap and the bulkhead will seal the overflow.
Sorry D, but no, that's not accurate. It would be true if the nut part of the bulkhead fitting were on the
outside of the tank, but it's not. The bulkhead nut goes inside the overflow box, which is
inside the tank, and the flange, with the important gasket on it, goes on the outside of the tank. Take a close look at Katy's picture of the bulkhead parts. You'll see what I mean.
The only two seals that really matter, will be the gasket on the flange of the bulkhead (which will be on the outside of the tank) and the silicone holding the glass piece (with the two 45mm holes drilled in it) to the back of the tank (also on the outside).
The silicone between the overflow box and the inside of the back wall Isn't really necessary (so forget my previous advice, and don't glue the box in (unless you are worried about it slipping out of level)) Water is going to leak along the threads of the bulkhead through the hole in the overflow box, through the hole in the back of the tank, and then be stopped by the two seals I described above, circumventing any silicone or gasket that are inside the tank. Water will pass between the threads of the nut, and the threads of the bulkhead, which are both inside the tank, as if the nut weren't there.
D was right about it being easier to use one piece of glass instead of two, as long as the holes are drilled to match the holes in the overflow box, I should have seen that. using two pieces is needlessly complicated. She's also right that this could be done using acrylic instead of glass, although it needs to be thick enough not to bow or crack. Glass is better, but acrylic might be easier to work with.