Reseal: is a new bead inside adequate?

Bought a somewhat grungy Craig's List 29 gal bowfront tank, and after cleaning it found that the thin edge of the silicon adhesive bead pulled away along about 8 inches of the front bottom joint (see pics). There are no leaks and the adhesive bead appears otherwise still tight except for this small area of loose "fringe" edge. The joints between the glass panel edges look sound. The tank is 8-10 yrs old, so I'd like to reseal it by removing the inside bead, then applying a new corner bead of adhesive on all inside seams if that would be adequate. Disassembling and reassembling the panels on this tank with 100% fresh adhesive is more of a project than I want to take on.

 

You can do that, but may not need to.

The primary seal is where the glass panels actually touch. If this is intact it is enough to hold water on it's own. What you are looking at is the secondary seal, which if your drawing is correct, is still sealed near the joint. If you want to reseal you have to carefully remove all traces of the old silicone it so the new silicone will properly adhere... it's a lot of work and may not turn out as well as you'd like.

You could just fill in a safe area like a garage or basement on a sheet of cardboard and let it sit for a week as a test. Most important is that it is placed on a flat surface so the tank isn't forced to "flex" when filled. This will help ensure a long lasting seal.

 

king Oscar is correct. the seal is between the panes of glass, not the "stripping" to smooth the transition of the 90 degree into a curved 90 degree. and it protects the silicone between the panes of glass. "butt bonding" (the two pieces together with each other in a 90) and "seam bonding" , (this is covering the butt bond to protect it from the water or other contaminants that would deteriorate the butt bond and smooth the 90 degree.
So the "seam bond" is sort of sacrificial in a way it's an added layer of protection.


Personally,. I would strip out all the seam bonding, careful not to mess up the butt bond between the glass, because all of the seam bond is likely near what has come off and will be more headache later on and without it, all you have is the butt bond left and it's exposed.

I would fill it in a safe location in case it leaks, to make sure the butt bonds of the glass panes are solid for a week and if that's fine, then re- seam bond it to protect the butt bonds again.

If the butt bonds are covered with seam bonds, and the seam bond is intact, there's no reason for the seal to pop. once you lose that protection and the butt bond is exposed it can weaken the butt bond \ and that butt bond can leak or pop and release.

in the TK bead picture,
the butt bond is the small bond between the two panes of glass where they are joined. in a 90 like an L.
The seam bond is the black triangle that is there to keep contaminants and water from affecting the butt bond. Ideally you'd want the seam bond there as extra protection for the lifetime of the tank.
Can you live without it? yeah, but it will eventually fail with with butt bond exposed.

 

Personally,. I would strip out all the seam bonding, careful not to mess up the butt bond between the glass, because all of the seam bond is likely near what has come off and will be more headache later on and without it, all you have is the butt bond left and it's exposed.

I would fill it in a safe location in case it leaks, to make sure the butt bonds of the glass panes are solid for a week and if that's fine, then re- seam bond it to protect the butt bonds again.

The tank was filled for several days for disinfecting. No leaks when filled to the brim. Are you saying that I should strip out all the corner seam bonds, then fill the tank again to check for butt bond leaks and then reseal the seams?

 

The tank was filled for several days for disinfecting. No leaks when filled to the brim. Are you saying that I should strip out all the corner seam bonds, then fill the tank again to check for butt bond leaks and then reseal the seams?

It's what I would do for longevity of the tank. But if it's not the whole seam bond come off and just the edge of it in the one area and the rest is still stuck down its likely fine and protecting the butt bond still.

Just if the seam bond has come off, the butt bond will eventually fail because it's no longer protected, matter of time.
If that happens replacing the seam bond is waranted to reprotect the butt bond as long as the butt bond hasn't been compromised.
If the butt bond is leaking, butt and seam bonds should be redone really. If the butt bond is solid just the seam bond should be done to protect the butt bond.

It's a 29g they are cheap however the bowfronts aren't cheap compared to rectangles. If it's compromised it's probably worth the resealing and learning for future 2nd hand tank purchases so you have confidence in doing it and don't pass on good deals that need work.

 

It's a 29g they are cheap however the bowfronts aren't cheap compared to rectangles. If it's compromised it's probably worth the resealing and learning for future 2nd hand tank purchases so you have confidence in doing it and don't pass on good deals that need work.

This one of the 29G bowfronts with center reinforcements, which the newer ones lack. I asked Tetra if they sell their bare bowfronts alone and they said no, only in the $340 full package. The stand is curved for bowfront, so only a considerably smaller rectangular tank would fit and look right.

 

This one of the 29G bowfronts with center reinforcements, which the newer ones lack. I asked Tetra if they sell their bare bowfronts alone and they said no, only in the $340 full package. The stand is curved for bowfront, so only a considerably smaller rectangular tank would fit and look right.

I like the center reinforcement, but the glass covers are kind of expensive when you need to replace them. I have a 72G bow, from all-glass aquariums (now aqueon) from back in the day. it's been a good strong tank for 30+ years of service. I can't complain, except for the lid replacement costs.