Plastic top-frame - how to remove?

[Andyroo]

Hi. I was gifed a couple of tanks over the years, 12, 15, 55gal, nothing huge. They're the pet-shop specials with the black plastic frame. That frame has now cracked leaving an unsightly (and frankly a little scary) gap as the tank fills & glass bows.

How to I remove the frame (to replace with glass cross-brace) without damaging the glass? It seems to be silicone'd in, so I'm thinking I'll have to carefully hacksaw and/or Dremmel, then blade & leverage

 

[Gourami Swami]

You can do it by squeezing a razor blade inbetween the glass and silicon all around the trim, as much as you can. Then you cut (dremel will be good for this) the plastic rim in a few places to break the rim into sections, and you carefully work the sections off. It is tricky to do- I have attempted it a few times, and got the rim off, but ended up with ugly chipped-up glass on top, and scrapped the tanks. Even if you do it perfectly, often these tanks have unfinished edges on top, because the manufacturers know they will be covered by the plastic brace anyway.
There are plenty of videos on youtube showing the process, here is one

 

[TheWolfman]

I have used a standard sheet rock knife. Cut the corner of the frame on the outside of the tank. Once you cut the corners of the frame you can brake the frame and it comes right off. Obviously be careful but it's not hard. Just take your time. After you remove the trim and old silicone grab some sand paper and water and give the top of the glass a wet sand to brake the edges.